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We live in CT.

I don't know the technical terms but our house configuration is:

  • Split level ranch (two floors plus attic)
  • Gas furnace and gas water heater in the basement
  • Air handler in the attic
  • Air condenser thingy outside
  • Our attic is not used for anything. We have a few boxes (like 5) and some empty suitcases.

My understanding is that water/air/something goes from the furnace or air condenser to the air handler which blows hot/cold air to the rest of the house.

We recently got solar panels. As part of the solar panel process, our electric company (Eversource) requires we get a home energy audit done by a home energy audit/assessment company. It just so happens to be that these home energy audit/assessment companies also give recommendations and you can pay them to do the recommendations. And, if you go with one of the recommendations, then Eversource gives a lot of credits/rebates -- which bring the price down by more than 50%.

This is the timeline of events:

  • Home energy audit/assessment company A sent by Eversource recommends we add a thick layer of cellulose insulation or fiberglass batting to the floor of our attic. They said they don't recommend spray foam between the roof rafters because we "have vented attic so insulating the roof would not improve the insulation value since outside air is allowed to enter the attic for ventilation." Not sure what that means.
  • I didn't know if I could trust home energy audit/assessment company A so I called Eversource to get the name of another home energy audit/assessment company. I had home energy audit/assessment company B come and they gave a similar recommendation as above.
  • I'm a paranoid person so then I found home insulation company C that is not linked to Eversource. They told me that putting the loose insulation on the attic floor will not help because then my attic will be hot/cold and that means my air handler will have to work harder. When the heat is on, the attic will be cold and when the cooler is on, the attic will be hot. Home insulation company C recommends I put spray foam spray in the roof rafters. This will make sure the attic is the same/similar temperature as the rest of the house and this will be better. They said all holes in the attic will be sealed. (Does that mean we won't have a vented roof anymore? Is that okay?)
  • As I said, I'm paranoid, so I called home insulation company D and they said pretty much the same thing as home insulation company C.

So now I'm kinda lost/confused. I don't know who is right and what I should do. I can't use the Eversource rebates/credits with the 2nd two companies, but I don't care about that if the foam spray is better for the house.

To recap:

  • Company A and Company B
    • Recommended by Eversource
    • Recommend loose insulation on attic floor
    • +50% credits/rebates from Eversource
  • Company C and Company D
    • No relation to Eversource; found independently
    • Recommend foam spray between roof rafters
    • No credits/rebates from Eversource

Also:

  • Since a very small area of our attic is used for storage, if we put loose insulation on the floor of the attic, we would not put insulation in a 5x5 area and would put some kind of hard board insulation down there.
  • The R value of all options is the same/similar.
  • Eversource is our electricity company. They do have incentive to lower our demand but they also have incentive to sell more electricity to make more $.
  • The house is 40+ years old but was updated recently. There is insulation under the floor of the attic (the area between the top floor and attic) but I don't think it's enough and we can't add more there.
  • The ducts coming out of the air handler are insulated. The air handler itself is not.

Can someone please help me with what is the better option and why?

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2 Answers 2

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There are 3 issues embedded in your question, so I'll separate them.

Issue 1 is the difference between a vented attic and a hot roof setup. A vented attic means that the roof stays cool, which helps prevent ice dams. You can also put a lot of insulation between the ceiling joists (what you call the "attic floor"), raising the R-value to 60 or more. That setup is undeniably good for your heating bill. A "hot roof" means that you put the insulation between the rafters (those are the pieces of wood holding the roof together). This increases the chance of ice dams, and is not as good for your heating bill as insulating the ceiling joists and venting the attic. The difference between loose fill insulation and fiberglass batts is another matter, but if you are not planning on using the attic for anything else later, then either one is fine as long as the R-value is identical. Other people will disagree on which one is better, but it's a matter of opinion (for the record, I prefer fiberglass.)

BTW, the company that said that you can't put insulation between the rafters because you have a vented attic is partially correct. But you can always seal the attic. Depending on your current setup, this might be as easy as closing a couple of vents, or as difficult as sealing ridge and soffit vents.

Issue #2 is that of the Eversource discounts. Get the estimates and speak with the power company directly, as some of the options will be free or nearly so. The installers will only care about what is easiest/cheaper for them to install. I live in the Northeast and they have come twice (different houses) to put loose fill in the attic, and both times it was free. The other work they did, my cost came to be a little above the cost of the materials, so it was a good deal and I didn't have to do the work myself. Still, the companies sent a bunch of hacks to do the job and I had to be there to direct them and check everything was done right. Otherwise they would have done a shitty job and then go collect their check from the power company. If I were not getting the discounts from the power company, I would just hire an independent insulation contractor.

Issue #3 is that of the air handler in the attic, and this is a question for the HVAC people. I'm no HVAC guy, but what I've seen is that all of the ducts end up being covered by the insulation, so the ducts will mostly be within the thermal envelope of the house. The air handler itself might stick out, but I would have to be convinced with data that the the heat loss/gain will be enough to offset the difference in heat loss between a vented attic and a hot roof. The question you need to ask is not "is the air handler better in an unconditioned attic or better within the thermal envelope?" because the answer will be "better within the thermal envelope". The question you need to ask the HVAC people is if the heat loss of having the handler in a vented attic will be greater than the heat loss of a hot roof setup.

The actual efficiency gains from doing this work at all will depend on how your house is currently insulated. In one of the houses I mentioned above, the annual heating fuel expense went from $2,000/yr to $500 after doing the energy efficiency improvements. In the second house, it did not make a difference.

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  • A question with three distinct issues should be closed as "needs focus".
    – isherwood
    Commented Oct 4, 2023 at 12:36
  • @isherwood The thing is, I didn't ask 3 distinct questions. I asked one question: which option should I go with. I didn't ask about discounts, rebates or air handler or anything. I just want to know, with my situation, what option is best. I put all the detail in the question cause I don't know what is relevant so I am sharing everything. It's not fair to me to close my question when I asked a very specific question. I even clearly ask it at the end: "Can someone please help me with what is the better option and why?". Commented Oct 4, 2023 at 16:20
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    @IMTheNachoMan But the answer to the question has to include the cost of the rebates, as the answer to that will determine what is "best" in your situation. For example, will you pay $30,000 in foam to save $500 per season? Or $500 in cellulose to save $600 per season? You see, it all depends on the numbers.
    – Cheery
    Commented Oct 4, 2023 at 16:25
  • @Cheery In this case I don't care about cost of insulation. I care about what will provide the best end result. For example, if A+B are cheaper, but C+D are right and having the air handler OUTSIDE the insulation will hurt the air handler, then even if A+B are cheaper it's still not a good option. It's not about cost today -- it's about cost for the next 20 years. I don't want to do A+B if it means the air handler will break faster. Commented Oct 4, 2023 at 16:27
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I just verified that Eversource is an actual utility. Much of my answer below was based on the idea that this company was purely a solar energy provider - i.e., a company that you contract with to install solar panels independently of your regular electricity supplier. With a real utility there is much more of a basis for discounts for energy improvements being "real" rather than a marketing game, because a real utility has incentive to lower peak demand, and one big way to lower peak demand is by lowering HVAC energy requirements.


My gut feeling:

  • Even with the rebates/discounts/etc., the cost will still be likely more than it is really worth - both from an energy saving standpoint (which is nominally the point of the insulation) and from a competitive standpoint. In other words, I wouldn't bother with A or B at all.
  • Loose fill or other insulation on the floor of the attic is easy (and that tends to mean profitable as well) so they recommend it. But I really do suspect it is not a good choice because of your HVAC situation.
  • Insulating the roof and sealing the attic makes the attic part of the rest of the house, from an HVAC standpoint. That can make a lot of sense. But that is complicated to do right.
  • Foam is good from an installation standpoint (unlike loose fill, it can go up right under the roof easily, rather than just down on the floor of the attic (=above your ceiling). But it is BAD from a fire safety standpoint. So I wouldn't bother with C or D because I'd be worried about them doing it right and I'd worry about the foam safety.

TL;DR Unless this is required (e.g., to get some part of the solar installation working) I would skip this for now.

Anecdotally, for reasons, I let my pest control company send an "inspector" from another department of the company to go into my attic, etc. and give a recommendation on redoing all the insulation in the attic, etc. The guy spent a lot of time climbing/crawling through nasty stuff. He gave me a $ amount but not formal proposal spelling out the work to be done. I said no because that's not how I do business. They later followed up by phone and I told them the same thing. Never got a formal proposal (1 page spelling out the basics is all I need) and they never got the business. Meanwhile, my HVAC is working fine, the regular pest control department took care of the actual pests, and life goes on. Be skeptical.

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    I will respectfully disagree with the first point. It all depends on how well your house is currently insulated. I will probably make no difference in a pre-1900 drafty house, but can make a huge difference in a 1950s to 1970s house that is mostly air tight but suffering from heat loss through the attic. I had such a house and the insulation work paid for itself in a single season.
    – Cheery
    Commented Oct 3, 2023 at 22:45
  • Dude's dealing with the rebate people. Yeah sure, no problem; government pays us to do this. (lose fill) - Ain't no spray foam company coming at you like that, and don't bother coming at them unless you got some serious dough in the bank.
    – Mazura
    Commented Oct 4, 2023 at 0:34
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    @Mazura Eversource is a public corporation, listed in the NYSE as SE. Hardly "the government"
    – Cheery
    Commented Oct 4, 2023 at 0:40

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