Does anyone have references to case studies (or quantifiable personal experience) that show specifics about how well ICF homes perform.  I'm specifically interested in BTU/SF/HDD values for ICF homes.

The reference, super insulated homes case study, provides analysis for several stick frame super insulated homes that were in the 1.3 BTU/SF/HDD range. I am interested in similar case studies for ICF homes.

I have yet to convince myself that ICF (or SIP) is the way to go from a high energy conservation standpoint in my 8000+ HDD location.

Thanks, Tom

I went to the link you provided and can't quite understand after reading the document that you would make a claim that "I have yet to convince myself that ICF (or SIP) is the way to go from a high energy conservation standpoint in my 8000+ HDD location".

The article in itself makes the claims that you use 1/4 to 1/3 the amount of energy to condition a super insulated structure. Perhaps energy efficiency isn't that important to you ?

Whole wall studies, which I think you can access at sips.org shows how a high performance building envelope works.

I've built over 50 custom homes using sips and icfs and supplied over 400 SIP and ICF packages to others and I've never gotten a report back that the home didn't perform as expected if not better.

It is my opinion that collectively, all of us and not due to our own fault, we've been trashing this earth for a long time now and it is time that we start giving back, by finding ways to cut significantly down on the need for fossil fuels besides all the other stuff of recycling, ect. - Building a sustainable home that cuts way down on energy needs is only one way to give back.

Besides the tree hugging stuff, I'd rather use my money for other important things, like buying beer or some music I like, verses give it to a utility company.

The Panel Guy

I obviously failed to communicate effectively.

None of the houses noted in the study were ICF or SIP. According to the report "Walls are R-50 15” staggered double 2x4, 16”oc, 15” standard density fiberglass batts..." These houses achieved between 0.90 and 1.50 BTU/SF/HDD.

I would like to achieve somewhere near 1.0 BTU/SF/HDD and if ICF or SIP cannot achieve that then I would like to eliminate them from my selection process.  My problem with ICF and SIP is that they may not be effecient enough! I can't find any quantifiable data from which to draw a conclusion.

I met with an owner of an ICF home and he was very happy with its performance but when I did the BTU/SF/HDD calculation for his house it was near 3.0, which is unacceptable to me.

Nope, I read it and understood it. However, apparently, my previous post was lost when M$'s Vista died. Thanks Bill.

With a bit less info. SIPS and ICF's will do you well. But, you are talking about Super Insulating(of which I'm an avid supporter). To get the R-Values that you are looking for(Ignore those Diminishing Returns people, they live in a world of stable energy costs, and that world is now just dust scattered about the universe), you'll need to Super Size. And I'm talking about 11.25" SIPS or ICF's with extra insulation on the inside(R-50 is a myth, especially in North Dakota).

Both SIPS & ICF's will reduce Air Infiltration, and that's one area in which they shine. You can get what you are looking for w/o stick framing.

Here's my theoretical ICF performance with Heating kwh from a Manual J analysis by Energywise. Using the format from the case study referenced in Tapper's original post:

Location: Wichita, KS Construction to start Aug 2008 4791 HDD 3098 SF

6056 kwh heating X 3412 Btu/kwh = 20,663,072 annual heating btu's

20,663,072 btu divided by 3098 SF = 6669 btu/sf

6669 but/sf divided by 4791 HDD = 1.39 btu/sf/HDD

This is designed as "typical, run-of-the-mill" ICF construction, not super-insulated. Also I expect actual performance will be better than the conservative theoretical so the energy figure above could be as low as 1.11 btu/sf/HDD.

ICF block is 2.75" thick EPS for total 5.5" and concrete is 6.25". Total wall thickness is 11.75"
Roof is unvented with 6" spray foam under roof deck.
Windows are low-E, triple pane, gas filled, aluminum clad wood.
Slab on grade has insulated at perimeter and 2" underslab insulation.

Using the same procedure for cooling I calculate 1.53 btu/SF/CDD (CDD is 1628 ), but don't know if this is a meaningful number on the cooling side.

Interesting way of looking at energy consumption.

Without proper ceiling/roof insulation and high quality windows and doors no wall system can contibute to it's greatest potential. In northern climates the foundation can also contibute to large heat losses. The workmanship in putting all of the components together also has a great bearing on the outcome.