# What are the best insulation options for an attic?



## turfnsurf

My goal is to cool the house as effectively as possible. In addition to lowering my energy bill, it would have the added benefit of reducing the workload on the HVAC system due to extreme heat.

Based on my reading, it sounds like either open cell or closed cell foam insulation might be the best option. Is this true?

I've heard about radiant barriers. It sounds like my home will not have one of those. At the time of this post, I don't know the r value of the insulation that my home will have. If it's something that will help shape the answers that I could get, I will try to obtain this information.


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## mrigney

Is this a house you're currently building? If so, is it a custom build? Semi-custom? Or are you retrofitting an existing home? If it's under construction, what stage of the build are you at?

I'll wait for those answers before I say too much. My general thoughts, though....

1) Open and closed cell are both potential solutions, but they're not the end all to insulation. Some of it depends on whether you'll have a vented and unconditioned attic space or an unvented/conditioned attic space.

2) Do whatever you can to get all of your ductwork inside the conditioned space of your house. E.g. If your ductwork is going to run in your attic, your insulation should go in the rafter bays, not on the floor of your attic. Bringing that ductwork inside the conditioned space is one of the most important things you can do. This requires some planning since you're (generally) limited to the depth of the rafter bay for insulation (or maybe you have trusses and don't even have a rafter bay), but there are always options.

3) Radiant barriers can be beneficial. I don't have the data off the top of my head. Even better (though again, you're moving into "weirdo" territory would be to put rigid foam on the exterior of your roof sheathing).

4) If at all possible, get a fully variable HVAC system. I see you're up north, so not as familiar with what the best options for up there are. Down south where I am, the best solution would generally be a fully variable speed heat pump. I have a 20 SEER system in my house with a few zones that can modulate capacity for each zone to pretty much the exact amount that that zone needs at the given time. So my 3-ton unit is hardly ever running at three tons. It can run as low as 0.6 tons if needed. This is more efficient and allows the unit to avoid short-cycling (running for too short of a period) which can cause moisture issues.

5) If you do go with spray foam, make sure you're handling fresh-air/ventilation. Up your way, this is probably an ERV or HRV; down here I might recommend a ventilating dehumidifier.


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## turfnsurf

mrigney said:


> Is this a house you're currently building? If so, is it a custom build? Semi-custom? Or are you retrofitting an existing home? If it's under construction, what stage of the build are you at?


It is a new build, but it's an inventory home. Not absolutely sure what that means, but I do know that the builder said that if we were interested in the home, that we would not be able to make modifications. Not sure if that's because another family designed it to spec and now it was too late or if there's some other reason why we can't make mods. So no extra closets or things like that.



> 1) Open and closed cell are both potential solutions, but they're not the end all to insulation. Some of it depends on whether you'll have a vented and unconditioned attic space or an unvented/conditioned attic space.


It is vented. Can you explain what you mean by 'conditioned'?



> 2) Do whatever you can to get all of your ductwork inside the conditioned space of your house. E.g. If your ductwork is going to run in your attic, your insulation should go in the rafter bays, not on the floor of your attic. Bringing that ductwork inside the conditioned space is one of the most important things you can do. This requires some planning since you're (generally) limited to the depth of the rafter bay for insulation (or maybe you have trusses and don't even have a rafter bay), but there are always options.


I will ask our builder what the setup is.



> 3) Radiant barriers can be beneficial. I don't have the data off the top of my head. Even better (though again, you're moving into "weirdo" territory would be to put rigid foam on the exterior of your roof sheathing).


I inquired about having a radiant barrier installed - they said they don't install those but they have some other comparable energy saving setup. I will need to ask about the r value of the installation that they will be installing.



> 4) If at all possible, get a fully variable HVAC system. I see you're up north, so not as familiar with what the best options for up there are. Down south where I am, the best solution would generally be a fully variable speed heat pump. I have a 20 SEER system in my house with a few zones that can modulate capacity for each zone to pretty much the exact amount that that zone needs at the given time. So my 3-ton unit is hardly ever running at three tons. It can run as low as 0.6 tons if needed. This is more efficient and allows the unit to avoid short-cycling (running for too short of a period) which can cause moisture issues.


I forgot what my current location says. I will be moving to Texas. According to our spec sheet, our system is only a 16 SEER Lennox HVAC with 410A refrigerant. Is that low quality? Also, is this variable speed heat pump something that I would need to buy after the fact and have installed? Are there any good ones that you can recommend?



> 5) If you do go with spray foam, make sure you're handling fresh-air/ventilation. Up your way, this is probably an ERV or HRV; down here I might recommend a ventilating dehumidifier.


Since I will be in Texas, what would you say differently about your answer to #5?


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## Ware

@turfnsurf what stage of construction is the home currently in? Have they started it? Is it nearing completion? It sounds like you have a copy of the specs. Have you signed a contract on it? Knowing those things will help frame responses to your questions.


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## BobLovesGrass

Inventory home likely means cookie cutter standard and any changes you want to make are going to be renovations at the end, changing mid stream during construction is a giant pain and cost.


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## corneliani

And who is the builder? National builders have their procurement processes locked up for the entire development and they won't deviate from their available options.
Edit to add: As for your insulation question, if your HVAC units are in the attic then the best insulation is one where your units get brought into the building envelope. Unfortunately the cheapest way to build is with blown-in insulation on top of the ceiling, and to change that after the fact will require you to vacuum all that insulation back up and insulate at the rafters. At least 2x the cost of doing it from the beginning, but that's the name of the game unless you go with a custom or even semi-custom builder.


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## mrigney

@Ware @BobLovesGrass @turfnsurf I'd assume inventory home means spec home as well. Probably does limit options significantly in terms of design. Some things might be worth changing after you move in, some might not be.

Before I ramble....you should ask if the builder does blower door tests or HERS ratings on his houses. If he doens't, I'd ask if you can hire a HERS rater to rate the house. A HERS rating will give you a blower door test (how airtight is the house), and will then take a look at all the other house specs (wall details, insulation package, appliances, HVAC, windows and window glazing, etc) and will provide you a rating on the efficiency of your house. Cost around here is $500 and includes the blower door test and final report. The score you get is based on a score of 100 being a reference house built to code. A score of 70 means your house would use 30% less energy than the reference house, a score of 130 means you'd expect to use 30% more.

Ventilation: I'd guess that most houses in TX (certainly most around here) won't have mechanical ventilation. The idea is that yes, a house needs to breath (but mainly b/c the occupants need fresh air, not because the house structure needs it), and mechanical ventilation gives you control over when/how much. For your situation with a spec house in Texas (unless you're way out in west TX in the desert), I might see if they can put a ventilating dehumidifier and duct it into your HVAC system. A pretty decent one is the AprilAire 8192. Could be something they can add, though again, w/a spec/inventory home I suspect they'll hassle you about it and/or charge you an absurd amount (should cost a few thousand including install). The ventilating dehumidifier pulls air in from outside the house (in an intelligent way), dehumidifies it, and then pushes it to your house (most of the time using your HVAC ducts, but you can duct it separately as well).

HVAC system: A 16 SEER is pretty standard these days. Nothing super energy efficient, but probably what you're going to get unless you ask for something different. That will probably have a one stage or two stage compressor. Imagine that as your throttle having one setting (wide open) or two settings (wide open, and maybe 60% of full throttle). This means that even if your house just needs a little conditioning, you're going to run at full blast (or 60% potentially with a two stage). A variable speed system can increment output in 1% increments (typically). So if you had a 3-ton system, it could effectively run at 3 tons, 2.97 tons, 2.94 tons, 2.91 tons, etc. I think Lennox's variable speed line is called XP. This is something you could ask about and might be able to upgrade (and I think is money well spent). Again, probably looking at a couple thousand extra over the unit you got quoted, but install between the two wouldn't be that different (duct work could be different based on whether your house has multiple zones, but that's a different story).

Conditioned attics: A conditioned attic is one where the attic is inside the insulated envelope of the house. So, for example, if your insulation is in the rafter bays in the attics, then your attic is "inside" the insulated envelope of the house, and thus "conditioned." In a typical unconditioned attic, temps in the summer in the south can easily be 120F+. So running ductwork through unconditioned attic space can lead to pretty big inefficiencies (even w/insulated ductwork). By making the attic conditioned space, your attic will stay within a few degrees of the rest of your house. In my house, I then had them (though you could do it yourself really easily) put one small register in the attic to help control humidity. My attic stays in the 70s winter and summer w/almost no heating/cooling cost.

Insulation: I'd probably just ask what their standard insulation package is and ask if there are any options. If you can get a list of what the different options are, I'm sure folks can give feedback. I'm no building professional...but it is a bit of a hobby of mine. Ha.


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## turfnsurf

Ware said:


> @turfnsurf what stage of construction is the home currently in? Have they started it? Is it nearing completion? It sounds like you have a copy of the specs. Have you signed a contract on it? Knowing those things will help frame responses to your questions.


@Ware it is at the pre-drywall stage. Working against my favor is that pretty much any "ask" is getting denied because it's already designed to spec.

We did sign the contract. The market has us over a barrel, and although we were looking to buy someone's pre-existing home, this takes us out of the contentious bidding war. And although some of the things aren't to my liking, it checks more boxes than it doesn't.

Their purchase contract has language indicating that (basically) if you're too difficult to deal with, they can back out. They've been good about letting me know what they can do (which is mostly nothing extra) vs what I might have to consider after the fact.

I have a copy of the specs...but it doesn't look like much. Would you like me to upload them?


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## turfnsurf

corneliani said:


> And who is the builder? National builders have their procurement processes locked up for the entire development and they won't deviate from their available options.
> Edit to add: As for your insulation question, if your HVAC units are in the attic then the best insulation is one where your units get brought into the building envelope. Unfortunately the cheapest way to build is with blown-in insulation on top of the ceiling, and to change that after the fact will require you to vacuum all that insulation back up and insulate at the rafters. At least 2x the cost of doing it from the beginning, but that's the name of the game unless you go with a custom or even semi-custom builder.


The builder is Castle Rock. Their link is https://www.c-rock.com/.

How does one know if the unit is brought into the building envelope? I have no idea what that means so I can't know one way or the other if this happened for me.


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## turfnsurf

mrigney said:


> Before I ramble....you should ask if the builder does blower door tests or HERS ratings on his houses. If he doens't, I'd ask if you can hire a HERS rater to rate the house. A HERS rating will give you a blower door test (how airtight is the house), and will then take a look at all the other house specs (wall details, insulation package, appliances, HVAC, windows and window glazing, etc) and will provide you a rating on the efficiency of your house. Cost around here is $500 and includes the blower door test and final report. The score you get is based on a score of 100 being a reference house built to code. A score of 70 means your house would use 30% less energy than the reference house, a score of 130 means you'd expect to use 30% more.


I will definitely be asking these questions.

At this point, I'm resigned to the fact that certain optimizations can't happen during the build, and would need to happen post occupancy. At this juncture, I am looking to find out the best questions to ask the builder and the best steps to take in preparation for this.



> Ventilation: I'd guess that most houses in TX (certainly most around here) won't have mechanical ventilation. The idea is that yes, a house needs to breath (but mainly b/c the occupants need fresh air, not because the house structure needs it), and mechanical ventilation gives you control over when/how much. For your situation with a spec house in Texas (unless you're way out in west TX in the desert), I might see if they can put a ventilating dehumidifier and duct it into your HVAC system. A pretty decent one is the AprilAire 8192. Could be something they can add, though again, w/a spec/inventory home I suspect they'll hassle you about it and/or charge you an absurd amount (should cost a few thousand including install). The ventilating dehumidifier pulls air in from outside the house (in an intelligent way), dehumidifies it, and then pushes it to your house (most of the time using your HVAC ducts, but you can duct it separately as well).


I will inquire about a ventilating dehumidifier and if I have to wait to do this post occupancy or not. For educational purposes, what does this do to enhance my home?

And secondly, do you know how a variable speed heat pump (that @mrigney mentioned) would work? I don't know how these systems behave, so I want to better understand how they work together.



> HVAC system: A 16 SEER is pretty standard these days. Nothing super energy efficient, but probably what you're going to get unless you ask for something different. That will probably have a one stage or two stage compressor. Imagine that as your throttle having one setting (wide open) or two settings (wide open, and maybe 60% of full throttle). This means that even if your house just needs a little conditioning, you're going to run at full blast (or 60% potentially with a two stage). A variable speed system can increment output in 1% increments (typically). So if you had a 3-ton system, it could effectively run at 3 tons, 2.97 tons, 2.94 tons, 2.91 tons, etc. I think Lennox's variable speed line is called XP. This is something you could ask about and might be able to upgrade (and I think is money well spent). Again, probably looking at a couple thousand extra over the unit you got quoted, but install between the two wouldn't be that different (duct work could be different based on whether your house has multiple zones, but that's a different story).


With my unit being 16 SEER and already installed, I know they won't upgrade. And with it looking like they cost $9K or more, I may just have to find another way to optimize based on what I have. Ugh.



> Conditioned attics: A conditioned attic is one where the attic is inside the insulated envelope of the house. So, for example, if your insulation is in the rafter bays in the attics, then your attic is "inside" the insulated envelope of the house, and thus "conditioned." In a typical unconditioned attic, temps in the summer in the south can easily be 120F+. So running ductwork through unconditioned attic space can lead to pretty big inefficiencies (even w/insulated ductwork). By making the attic conditioned space, your attic will stay within a few degrees of the rest of your house. In my house, I then had them (though you could do it yourself really easily) put one small register in the attic to help control humidity. My attic stays in the 70s winter and summer w/almost no heating/cooling cost.


Would conditioned attics be when people get foam encapsulation in the roof decking? I am attaching a photo of what I believe in foam encapsulation...or what you're calling a conditioned attic.





> Insulation: I'd probably just ask what their standard insulation package is and ask if there are any options. If you can get a list of what the different options are, I'm sure folks can give feedback. I'm no building professional...but it is a bit of a hobby of mine. Ha.


I appreciate everything you and everyone is sharing.

I don't know what the best options are for me, given that I can't make the best changes pre-drywall.


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## Ware

Unfortunately to @BobLovesGrass and @corneliani's point, some of these upgrades would need to have been worked out prior to signing a contract for the plans and specs you were provided. Changing now would be sort of like ordering an F-150 XLT from the factory and then deciding halfway through the build that you really wanted the King Ranch trim package.


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## mrigney

Yeah, will be hard to change a lot now. On the other hand, you're on a board full of folks who, I think, view home projects and maintenance as a long-term passion. So think of this as an opportunity to start with a ready-made list of projects to tackle over the next decade


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## turfnsurf

I had a bad feeling that the most meaningful improvements are made during the design phase.

Given that this wasn't going to be an option for me, what do you all think I can do with what I have to optimize my situation?


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## Ware

turfnsurf said:


> I had a bad feeling that the most meaningful improvements are made during the design phase.
> 
> Given that this wasn't going to be an option for me, what do you all think I can do with what I have to optimize my situation?


Don't beat yourself up. You will end up with a pretty normal home. I wouldn't lose sleep over it.


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## BobLovesGrass

Modern homes are pretty tight, I think you will be happy.


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## mrigney

Yeah, I meant to say what @Ware and @BobLovesGrass have both pointed out now. A house built to 2015 IRC (or whatever recent version your city is on) is still going to be a pretty good house. For some reference, I used to live in spec house built by a huge national builder (DR Horton). If I remember correctly, the HERS rating on that house was 84. So even it ended up better than code.

I would take the house, enjoy it, and then once you've been in a year, put together a few projects that you think might be fun and that you'd enjoy doing. Having just finished a custom build 6 months ago, I know that it's really easy to beat yourself up through the process, or get frustrated by things that really end up outside your control. Don't do it. My wife and I have tried to instead think about all of the great things in the house that we got that we wanted.


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## ptf18+6

We live in new single story house (2021) in East Texas. It is "encapsulated". It also has the latest "fad" 12/12 pitch roof which makes the attic GIGANTIC. While working in the attic this past summer (2021) and now winter (2021-2022) I found that it was quite comfortable....too comfortable.

There's a cost keeping that Gigantic (unusable) attic comfortable and I see it every month when paying the .11 per kilowatt/hour electric bill. I am starting to feel that while encapsulating a house (spray foam under the roof) may work in theory, the cost/benefit goes away when attic become too large.

I'm going to start foam sealing all the openings in the ceiling sheet rock that are around ceiling mounted light and fan junction boxes. Later I will start laying batted insulation on the sheet rocked ceilings at least over some of our rooms. My intention is NOT to insulate the living areas from the attic but rather to slow down the energy transfer into the attic making the attic abit uncomfortable to be in. As for humidity control, I will be monitoring that with humidity/temp gauges.

I do believe that Texas is pretty (too) "relaxed" when it comes to energy conservation and the OP sees that when bringing up issues that concern him. I realize that its a "spec" home but it is also 2022 and we do have the "technology" that makes for LONG TERM energy savings...... Builders don't care... pretty paint and fancy floors make the sale and most buyers have no clue (and could care less) about energy costs...... until they get that bill every month. Even then they might moan about it but few do anything about it.

Good Luck to the OP.


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## Ngilbe36

Slightly different perspective, but similar advice to Ware and Boblovesgrass. I just did a complete, back down to bare foundation walls, ripped out all the wiring, 18 month (I work slow) renovation to my basement. I planned and planned and did everything I could to future proof and make everything perfect. At the end of the day, there are things I wish I did different, but its a great space and we enjoy it much more than we used to. Point is, enjoy your amazing new home, if some of these things bother you down the road after you've lived in it you can always make changes.


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## corneliani

@turfnsurf I think it's worth stepping back a bit and, in line with what the others are mentioning, look at the big picture. The question you posed was 'what are the best insulation options"... and the answer will most likely leave you feeling like you're getting a somewhat inefficient - or possibly insufficient house - if you're not getting 'the best' insulation available. Don't look at it that way. The "best" isn't always the one that fits your situation/priorities best. For ex I need new suspension on wifes BMW. The tech is pushing me towards "the best" shocks&struts and I opted for the 2nd/3rd best.. because in the grand scheme of things I didn't find value in the "performance" upgrade he was so passionate about. His "the best" was not mine, and it wouldn't fit our use & style of driving anyhow.
So yes, there's always a "better" product out there but it's all part of a system, and insulation is especially system-based. Roof insulation is important as that's where most of the heat loss occurs, but if you have a drafty house you can blow in 4" of closed-cell and it won't matter one bit! You're only as strong as your weakest link. On top of it all, if you were to do any ROI or breakeven analysis on these somewhat custom specs you'll find that it takes a good 10+ years to break even! You can accomplish acceptable levels of insulation and comfort using "inferior" products, if installed correctly. I have a feeling @mrigney would agree with me on this.

I write all this because the last thing you want is someone getting into a beautiful new home and feeling like they missed out bc they didn't have the latest/greatest product. Look at the big picture... all those options would have increased the cost of the house significantly!

Btw I'm a custom homebuilder, for what its worth, and these options mentioned in this thread are par for the course when your products are $1M+. Hardly ever included in spec homes though.


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## Ware

I agree with everything @corneliani said. When building a new home there is opportunity to upgrade every. single. thing. At the end of the day most people (people with a budget) must prioritize and choose where they want to spend their money.

He made a great point about paying attention to the ROI for certain upgrades too. For example, if I run a calculator like this one to compare the energy savings of a 20 SEER over a 16 SEER air conditioner using my local electricity rates and the average annual cooling hours from the ASHRAE tables for my location, the energy savings over the expected useful life of the unit are less than the incremental cost I was quoted to upgrade. There are obviously some other benefits of a variable speed system to consider, but the point is even energy 'savings' come at some cost.

I also think builders catch hell sometimes for not upgrading this or that when building a new home. I see the term 'builder grade' thrown around a lot, but I think it could just as easily be called 'customer grade' because they are merely building a product that their customers can afford and are willing to pay for. When the NAHB updated their price-out study last year, estimates indicated that every $1,000 increase in the median price of a new home in the U.S. prices about 154,000 households out of the market.

To continue with the F-150 analogy I used earlier this thread - expecting builders to always use only the very best materials and technologies available would be like a Ford dealership only stocking trucks with the Platinum, Raptor and Limited trim packages. It's great that those options exist, but the truth is not everyone can afford them. This is especially true with the inflated material costs we see today.


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## turfnsurf

I want to thank you all for the perspective. I am going to definitely focus on all of the good that comes with a new home. I am very thankful and appreciate of my situation...in part because the home is new, but mostly because it allows us to relocate. We really want to be in the city we're moving too, and there's been a ridiculous amount of demand, so getting a new home was better for us for mostly because it ensures that we don't have to compete with other people because then there wouldn't be a guarantee that we could move.

My main reason for asking for the insulation options had less to do with ROI. 
While I definitely care about that, I am not certain how long I will be in this how, so my ask had more to do with preserving my system from the taxing heat in the attic. I don't know HVAC systems well, so I was contemplating is it conceivable that it could break down because of heat before ROI even would factor in.

I am going to tag the people who made comments, but anyone feel free to chime in.



mrigney said:


> If you do go with spray foam, make sure you're handling fresh-air/ventilation. Up your way, this is probably an ERV or HRV; down here I might recommend a ventilating dehumidifier.


@mrigney can you recommend one? And is this part of the HVAC 'system' and needs to be installed in some way, or some separate plug-in device? dehumAnd lastly, what will this help in?



mrigney said:


> Before I ramble....you should ask if the builder does blower door tests or HERS ratings on his houses. If he doens't, I'd ask if you can hire a HERS rater to rate the house. A HERS rating will give you a blower door test (how airtight is the house), and will then take a look at all the other house specs (wall details, insulation package, appliances, HVAC, windows and window glazing, etc) and will provide you a rating on the efficiency of your house. Cost around here is $500 and includes the blower door test and final report. The score you get is based on a score of 100 being a reference house built to code. A score of 70 means your house would use 30% less energy than the reference house, a score of 130 means you'd expect to use 30% more.


@mrigney if I am able to get this test done, what's my next move? If there are ways to optimize the house, do I need to know what I want to do, or does the test typically come with recommendations?



mirigney said:


> If at all possible, get a fully variable HVAC system. I see you're up north, so not as familiar with what the best options for up there are. Down south where I am, the best solution would generally be a fully variable speed heat pump. I have a 20 SEER system in my house with a few zones that can modulate capacity for each zone to pretty much the exact amount that that zone needs at the given time. So my 3-ton unit is hardly ever running at three tons. It can run as low as 0.6 tons if needed. This is more efficient and allows the unit to avoid short-cycling (running for too short of a period) which can cause moisture issues.


Is the fully variable speed heat pump a separate device, or is it part of your furnace? When you say 'fully variable HVAC system' and '20 SEER system' is this referring to other components outside of the furnace? I just want to make sure I understand what the 'system' consists of. Would you mind sharing a link to the one you have? I'd like to check it out on youtube to understand how it operates.

To ALL: After speaking to someone, I cannot do the foam encapsulation because I have a standard furnace with the lower AFUE. I would need a furnace with 95% AFUE or an electrical furnace - they said something about the waste fumes in mine being too high and could lead to health issues or death if I encapsulated my attic.

Because of this, I could consider radiant barrier options, and having a solar fan to draw the heat out of my attic. Are there any other options that you all would consider? I am trying to shore up my education on this radiant barrier.


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## BobLovesGrass

When I moved into my current house there was a very poorly installed high velocity system. By poorly install d I mean the bedrooms on the north end of the house right under the attic unit had 2 ports each, same as the mostly glass living room with skylights on the south end of the house.........
The system was still functional when I replaced it with mini splits.
The attic was hot in summer 1970s construction, poorly vented. The system made the bedrooms 65f while the living room was 80f. Efficiency seemed to be hurt by the hot environment but not service life. It was close to 20 years old when I had it disconnected and had no service the last 6 years, no idea before that.


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## jayhawk

turfnsurf said:


> I want to thank you all for the perspective. I am going to definitely focus on all of the good that comes with a new home. I am very thankful and appreciate of my situation...in part because the home is new, but mostly because it allows us to relocate. We really want to be in the city we're moving too, and there's been a ridiculous amount of demand, so getting a new home was better for us for mostly because it ensures that we don't have to compete with other people because then there wouldn't be a guarantee that we could move.
> 
> My main reason for asking for the insulation options had less to do with ROI.
> While I definitely care about that, I am not certain how long I will be in this how, so my ask had more to do with preserving my system from the taxing heat in the attic. I don't know HVAC systems well, so I was contemplating is it conceivable that it could break down because of heat before ROI even would factor in.
> 
> I am going to tag the people who made comments, but anyone feel free to chime in.
> 
> 
> 
> mrigney said:
> 
> 
> 
> If you do go with spray foam, make sure you're handling fresh-air/ventilation. Up your way, this is probably an ERV or HRV; down here I might recommend a ventilating dehumidifier.
> 
> 
> 
> @mrigney can you recommend one? And is this part of the HVAC 'system' and needs to be installed in some way, or some separate plug-in device? dehumAnd lastly, what will this help in?
> 
> 
> 
> mrigney said:
> 
> 
> 
> Before I ramble....you should ask if the builder does blower door tests or HERS ratings on his houses. If he doens't, I'd ask if you can hire a HERS rater to rate the house. A HERS rating will give you a blower door test (how airtight is the house), and will then take a look at all the other house specs (wall details, insulation package, appliances, HVAC, windows and window glazing, etc) and will provide you a rating on the efficiency of your house. Cost around here is $500 and includes the blower door test and final report. The score you get is based on a score of 100 being a reference house built to code. A score of 70 means your house would use 30% less energy than the reference house, a score of 130 means you'd expect to use 30% more.
> 
> Click to expand...
> 
> @mrigney if I am able to get this test done, what's my next move? If there are ways to optimize the house, do I need to know what I want to do, or does the test typically come with recommendations?
> 
> 
> 
> mirigney said:
> 
> 
> 
> If at all possible, get a fully variable HVAC system. I see you're up north, so not as familiar with what the best options for up there are. Down south where I am, the best solution would generally be a fully variable speed heat pump. I have a 20 SEER system in my house with a few zones that can modulate capacity for each zone to pretty much the exact amount that that zone needs at the given time. So my 3-ton unit is hardly ever running at three tons. It can run as low as 0.6 tons if needed. This is more efficient and allows the unit to avoid short-cycling (running for too short of a period) which can cause moisture issues.
> 
> Click to expand...
> 
> Is the fully variable speed heat pump a separate device, or is it part of your furnace? When you say 'fully variable HVAC system' and '20 SEER system' is this referring to other components outside of the furnace? I just want to make sure I understand what the 'system' consists of. Would you mind sharing a link to the one you have? I'd like to check it out on youtube to understand how it operates.
> 
> To ALL: After speaking to someone, I cannot do the foam encapsulation because I have a standard furnace with the lower AFUE. I would need a furnace with 95% AFUE or an electrical furnace - they said something about the waste fumes in mine being too high and could lead to health issues or death if I encapsulated my attic.
> 
> Because of this, I could consider radiant barrier options, and having a solar fan to draw the heat out of my attic. Are there any other options that you all would consider? I am trying to shore up my education on this radiant barrier.
Click to expand...

just one system in the attic for the entire house? If no, they are saying std furnace in the basement but don't dare spray the rafters in the attic? (So we're counting on the home to leak enough not kill ya from the basement setup?)

It's life will be shorter for sure w/o an encapsulated.


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## turfnsurf

So I found out a couple of things from the builder.

* They are performing a blower test and the HERS rating is available at the home's completion.

* I asked if the ductwork is inside the conditioned space of the attic and if the insulation in the rafter bays. I was told that the ductwork is in the attic and the attic is not air conditioned. It is insulated with 14 inches of blown in insulation.

Because I don't know much about insulation, the 2nd response feels non-responsive and evasive.

What are my next moves based on this information?


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## jayhawk

Re next moves - you could consult with Energy Vanguard in Atlanta.
They are performance geeks, not equipment sellers.


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## Ware

turfnsurf said:


> So I found out a couple of things from the builder.
> 
> * They are performing a blower test and the HERS rating is available at the home's completion.
> 
> * I asked if the ductwork is inside the conditioned space of the attic and if the insulation in the rafter bays. I was told that the ductwork is in the attic and the attic is not air conditioned. It is insulated with 14 inches of blown in insulation.
> 
> Because I don't know much about insulation, the 2nd response feels non-responsive and evasive.
> 
> What are my next moves based on this information?


14 inches of blown attic insulation gets you to R-38, which is pretty standard for homes in southern climates. The R-value per inch will vary a little depending on the type (e.g. fiberglass or cellulose).

If you didn't agree to pay for an encapsulated attic or other insulation upgrades, you are getting what I would expect to see in a new home built in Texas.


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## mrigney

Yeah, the answer you got about attic insulation is pretty normal and a standard attic insulation job. Nothing wrong with it. Not "optimal" per se, but also the way that probably 95% of homes in the south are built (maybe more than 95%).

I second @jayhawk's Energy Vanguard recommendation. They are exclusively HVAC designers. Again, I would consult with them down the road if you want, or you could just read Allison Bailes' (the owner) blog for tons of good information.

@turfnsurf To try to answer some of the questions that you asked me and I never answered....

My system: https://www.carrier.com/residential/en/us/products/heat-pumps/25vna0/ It's a heat pump, so I don't have a separate furnace. This single unit does my heating and cooling. This is it (plus an air handler that sits in my attic).

ERVs: AprilAire makes pretty decent products. Here is an example: https://www.aprilaire.com/whole-house-products/ventilation/model-8100 The role of the ERV (or a ventilating dehumidifier) is to bring in fresh air to the house. All houses breath. Old houses (or poorly built ones) breath through the walls where their are leaks. New houses tend to be tighter, and an ERV controls the flow of air into your house by letting in air in prescribed manner (and it conditions and dehumidifies some in the process as well as filters). Think of it as breathing in through your nose instead of breathing by letting oxygen seep in through your skin by osmosis. You can install them and use the same ductwork as your hvac system or install them completely separately. Your house design will dictate how easy it is to retrofit one.

HERS rating. I think the HERS rating is just good to have. It gives you a reference for where your house is at. Also, your HERS rater can be a great source of information down the road if you can build a relationship with them.


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## turfnsurf

Ware said:


> 14 inches of blown attic insulation gets you to R-38, which is pretty standard for homes in southern climates. The R-value per inch will vary a little depending on the type (e.g. fiberglass or cellulose).
> 
> If you didn't agree to pay for an encapsulated attic or other insulation upgrades, you are getting what I would expect to see in a new home built in Texas.


@Ware I was told by several people that I can't have an encapsulated attic because my conventional furnace has too high of waste.

Apparently they only do it with the 95% furnaces or an electrical furnace. I think mine is 80 or 85. Whatever most folks had. Too bad, so sad for me. If you have any other tips, I am all ears. It's impressive how much you all know.


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## turfnsurf

mrigney said:


> My system: https://www.carrier.com/residential/en/us/products/heat-pumps/25vna0/ It's a heat pump, so I don't have a separate furnace. This single unit does my heating and cooling. This is it (plus an air handler that sits in my attic).
> 
> ERVs: AprilAire makes pretty decent products. Here is an example: https://www.aprilaire.com/whole-house-products/ventilation/model-8100 The role of the ERV (or a ventilating dehumidifier) is to bring in fresh air to the house. All houses breath. Old houses (or poorly built ones) breath through the walls where their are leaks. New houses tend to be tighter, and an ERV controls the flow of air into your house by letting in air in prescribed manner (and it conditions and dehumidifies some in the process as well as filters). Think of it as breathing in through your nose instead of breathing by letting oxygen seep in through your skin by osmosis. You can install them and use the same ductwork as your hvac system or install them completely separately. Your house design will dictate how easy it is to retrofit one.
> 
> HERS rating. I think the HERS rating is just good to have. It gives you a reference for where your house is at. Also, your HERS rater can be a great source of information down the road if you can build a relationship with them.


Do you mind sharing why you chose a heat pump over a furnace? I never heard of those before, but I just watched a couple of videos on them. I looked at this article to get a sense for a comparative analysis.

I am now actually curious if there's a tool that efforts to compare a furnace/AC setup vs a heat pump setup (in areas without harsh winters)

I am interested in this AprilAire system. I wanted some sort of filtration system to improve the air quality given that I have asthma, and some allergies.

Is this something that is a person who isn't handy can do? Or is this best done by a professional if you aren't handy? 
Do you mind sharing how much this costs? Their site isn't providing any pricing data that I can find, and they are redirecting me to "professionals in my area", so I am not even sure they let you purchase this directly.

Lastly, do I need to consider a dehumidifer for my attic since that's where my HVAC will be? Not sure if moisture is an issue with HVAC above the living area.


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## jayhawk

For whatever reason, I thought you in a warm climate. I believe an HRV (vs ERV) is what you'd ultimately want. They will warm the incoming fresh air. Broan, Honeywell are additional examples in the reasonable price range. I don't have any data but I'd compare how much energy is required to operate them... might be a difference.

Regardless, 'upgrade' the HVAC filter to a 4" so you can put in higher merv filter without choking the system. (Similar to Breathing thru a N95 vs a surgical) The box that holds them was $150 but they will charge you double.


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## turfnsurf

jayhawk said:


> For whatever reason, I thought you in a warm climate. I believe an HRV (vs ERV) is what you'd ultimately want. They will warm the incoming fresh air. Broan, Honeywell are additional examples in the reasonable price range. I don't have any data but I'd compare how much energy is required to operate them... might be a difference.


My guess is you looked at my profile. My relocation to the warmer climate is official in a couple of months. I just updated my profile so that it won't confuse anyone else. I'll definitely look at Broan and Honeywell too. Thanks.



> Regardless, 'upgrade' the HVAC filter to a 4" so you can put in higher merv filter without choking the system. (Similar to Breathing thru a N95 vs a surgical) The box that holds them was $150 but they will charge you double.


My specs says that my setup has fresh air intake and a media filter. And now that I think about it, my current home has an Aprilaire AirGard that I bought some filters for. I just need to determine what is a MERV rating to buy.


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## r7k

turfnsurf said:


> My goal is to cool the house as effectively as possible. In addition to lowering my energy bill, it would have the added benefit of reducing the workload on the HVAC system due to extreme heat.


if you have an asphalt shingle roof, getting it re-roofed to an aluminum roof would help the most.

the heat is purely radiation, and re-radiation underneath the asphalt shingle roof (and not conduction or convention).

Dealing with the re-radiation of the asphalt shingles underneath the roof is difficult, they do make radiation reflective type material (AL foil type stuff) that gets place between the joists underneath the roof within the attic, but how well that works and how well that causes your shingles and plywood roof to cook I don't know... the heat has to go somewhere.

with having a asphalt shingled roof having good attic venting is probably the best most cost effective solution to move that heated air out of the attic on hot sunny days. the ridge vent basically does not work. having as large as possible gable vents on each end that have no obstructions is step 1; step 2 would be power venting to move the heated air out of the attic. step 3 would be putting a few through roof vents, that would exhaust the hot air (hot air up and out) somewhat naturally but ideally having power vents on them and having cool outside air come in through the gable vents.

and then R-38 or whatever insulation that will fit on your attic floor between the joists. Foil faced insulation, as opposed to typical paper backed, will act as a radiant barrier and keep that radiation from heating the living space below but would of course reflect the radiation within your attic, which you take care of with either power venting or an aluminum roof to stop the radiation before it ever enters into the attic


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## Schreibdave

I second (or third/fourth) the Alison Bailes blog. Also check out Building Science Corporation's web site founded by Joe Lstiburek. And Matt Risinger is a custom builder in Austin, Texas who does some very interesting youtube videos on building science.

There is a very deep rabbit hole around these subjects and it sounds like you are about to fall in to it - I did. My last 2 builds were better as a result of all the research I did but you will never be able to implement all the things that are "best practice" because doing so requires a custom home and an unlimited budget. The more you know, the more you will drive yourself crazy.

It sounds like this isn't your "forever home" so learn what you can, make modifications to it where practical and be ready next time you are building a new home. But be prepared for builders to tell you "we dont do that, you dont need that, that's not how it's done, etc etc."

Good luck!


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## jayhawk

Schreibdave said:


> I second (or third/fourth) the Alison Bailes blog. Also check out Building Science Corporation's web site founded by Joe Lstiburek. And Matt Risinger is a custom builder in Austin, Texas who does some very interesting youtube videos on building science.
> 
> There is a very deep rabbit hole around these subjects and it sounds like you are about to fall in to it - I did. My last 2 builds were better as a result of all the research I did but you will never be able to implement all the things that are "best practice" because doing so requires a custom home and an unlimited budget. The more you know, the more you will drive yourself crazy.


Dave 
Ain't that the Truth! (The More you know)
Bailes' blog is good.


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## turfnsurf

Schreibdave said:


> I second (or third/fourth) the Alison Bailes blog. Also check out Building Science Corporation's web site founded by Joe Lstiburek. And Matt Risinger is a custom builder in Austin, Texas who does some very interesting youtube videos on building science.


Thanks for chiming in. Appreciate all the feedback.



> There is a very deep rabbit hole around these subjects and it sounds like you are about to fall in to it - I did. My last 2 builds were better as a result of all the research I did but you will never be able to implement all the things that are "best practice" because doing so requires a custom home and an unlimited budget. The more you know, the more you will drive yourself crazy.


Yeah I definitely fell in. It's too bad I didn't have a foundation for this kind of thing going in.


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## turfnsurf

r7k said:


> if you have an asphalt shingle roof, getting it re-roofed to an aluminum roof would help the most.
> 
> the heat is purely radiation, and re-radiation underneath the asphalt shingle roof (and not conduction or convention).


Are you aware of any information that illustrates either energy savings or cooling differences between these two options? I am going to look, however I am curious about any sources that you might know as well.


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## ag_fishing

Ware said:


> turfnsurf said:
> 
> 
> 
> So I found out a couple of things from the builder.
> 
> * They are performing a blower test and the HERS rating is available at the home's completion.
> 
> * I asked if the ductwork is inside the conditioned space of the attic and if the insulation in the rafter bays. I was told that the ductwork is in the attic and the attic is not air conditioned. It is insulated with 14 inches of blown in insulation.
> 
> Because I don't know much about insulation, the 2nd response feels non-responsive and evasive.
> 
> What are my next moves based on this information?
> 
> 
> 
> 14 inches of blown attic insulation gets you to R-38, which is pretty standard for homes in southern climates. The R-value per inch will vary a little depending on the type (e.g. fiberglass or cellulose).
> 
> If you didn't agree to pay for an encapsulated attic or other insulation upgrades, you are getting what I would expect to see in a new home built in Texas.
Click to expand...

Geez. I can see the tops of the studs poking through my 20 year old attic insulation. I'd hate to know what my R value actually is up there :shock:


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## MasterMech

Ware said:


> ...
> they are merely building a product that their customers can afford and are willing to pay for.
> ....


Builders here are certainly taking advantage of that and pricing on what the market will bear, not what materials cost and their necessary/typical margin. A new build that sold for $350k here 5 years ago, now sells for nearly $600k+. Same builders, same neighborhood, same (lower tier) materials, same builder's grade finishes and fixtures. Same everything. The builder in my neighborhood stopped offering stone facade, (vinyl, or brick as an upgrade), and yet the prices continue to skyrocket.

I'm not saying we all need marble floors, but would it kill them to run Cat 6 from a utility room/closet to each TV drop by default? Why is a fan-rated ceiling box an extra-cost option, in the Deep South no less? :bd: A 5/8" water meter supplying 5+ BR/4BA homes with full irrigation systems.... and not a stick of plumbing in the home is larger than 1/2" Pex. Trunk and branch plumbing feeding 4 full bathrooms. Yeah, I've got 4 bathrooms, but forget about using more than 2 at the same time, especially if the washer is running. Often the customer is pretty ignorant about things that can really benefit them or affect their enjoyment of the home in the long run. He wants a 3-car garage, she wants white cabinets, and by the time the build is finished, it's way too late to address energy, data/communications, lighting, etc. And then the bills start rolling in. If these minor upgrades swing the needle $10k on the total price of the home, is it really a question of affordability on a $200k+ purchase (especially one being amortized out 15+ years?), let alone the $500k+ these houses around me are going for? Or is it more likely a matter of capitalizing on the customer's ignorance and pocketing an extra $10k on thousands of home builds annually? :thumbup: They do a great job selling the finishes, cabinetry, and the appliances..... why doesn't infrastructure of the home get that same attention? The big builders care about closing on the home, and hope the warranty runs out before the customer is stuck with the (often monthly) bill for their apathy. The warranty repairs are then short-term cosmetic fixes to kick the can down the road just far enough.

If we built cars this way, customers would be LIVID. But for some reason it's ok for housing, at least in the USA.


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