Posted By Lbear on 13 Jan 2012 11:56 AM

And that is why ICF is not catching on as it should. When you have a 15%-20% upcost just for doing ICF over wood, most middle income people will pass it up and go with wood. For now, ICF mostly caters to commercial and upper income people.


Comparing a standard code minimum frame house to an ICF is pennywise pound fuelish. Even if the up charge is 15%. Amortize it over your mortgage and then compare it to the cost of the stick frame and the associated heating bill. In other words what is your total monthly cost? And remember, you will eventually pay off the mortgage. You will never pay off your utility bill!

Posted By FBBP on 13 Jan 2012 09:42 PM


Comparing a standard code minimum frame house to an ICF is pennywise pound fuelish. Even if the up charge is 15%. Amortize it over your mortgage and then compare it to the cost of the stick frame and the associated heating bill. In other words what is your total monthly cost? And remember, you will eventually pay off the mortgage. You will never pay off your utility bill!

Don't get me wrong, I am most likely going to build with ICF.

The problem with what you are stating is that it does not compute. On a $300k home, that 15% = $45k. I can build a tight 2x6 home, blow in R-22 in the wall (which is the same R-value of ICF), and save myself $45k. It would take 50 years to break even in utility bills. Where is the savings?

For me, I would utilize ICF based on its strength, termite resistance, fire resistance, air tightness, and when engineered correctly, its seismic resistance. The insulating value of ICF does not really win me over. I know that there are many 2x6 wood frames homes that can meet or outperform an ICF home in regards to R value. What I also do know is that in a high wind situation or storm, I would rather be in an ICF home than a wood framed home.

Going into this, I know I will never see a ROI for ICF.

Posted By Lbear on 14 Jan 2012 01:04 AM

Posted By FBBP on 13 Jan 2012 09:42 PM


Comparing a standard code minimum frame house to an ICF is pennywise pound fuelish. Even if the up charge is 15%. Amortize it over your mortgage and then compare it to the cost of the stick frame and the associated heating bill. In other words what is your total monthly cost? And remember, you will eventually pay off the mortgage. You will never pay off your utility bill!

Don't get me wrong, I am most likely going to build with ICF.

The problem with what you are stating is that it does not compute. On a $300k home, that 15% = $45k. I can build a tight 2x6 home, blow in R-22 in the wall (which is the same R-value of ICF), and save myself $45k. It would take 50 years to break even in utility bills. Where is the savings?

For me, I would utilize ICF based on its strength, termite resistance, fire resistance, air tightness, and when engineered correctly, its seismic resistance. The insulating value of ICF does not really win me over. I know that there are many 2x6 wood frames homes that can meet or outperform an ICF home in regards to R value. What I also do know is that in a high wind situation or storm, I would rather be in an ICF home than a wood framed home.

Going into this, I know I will never see a ROI for ICF.

Lbear - we could go into the actual values for ICF again and some of the folks on this forum would get all excited about how the ICF industry over states the insulation values of their product but its simpler to once again refer you to a thread like http://www.greenbuildingtalk.com/Forums/tabid/53/aff/12/aft/79652/afv/topic/Default.aspx.
Yes HVAC-Calc uses a low R value for ICF but how do you explain the final heat loss numbers? Your same size 2x6 with blow will not maker these numbers. Furthermore your 2x6 house will not make the same numbers ten years from now as it does today.
What I find interesting is that it is always number crunchers that say the ICF industry over states the products performance but I have yet to hear from someone living in an ICF house that they were lied to. You mention all sorts of things that are wrong with the industry and why it can't get ahead but the industry continues to turn out a very high percent of satisfied customers.

I have yet to hear from someone living in an ICF house that they were lied to.

Do you know anyone living in an ICF house that has the ability to do a properly controlled comparison to equivalent R and infiltration value stick framing?

Posted By jonr on 14 Jan 2012 09:57 PM

I have yet to hear from someone living in an ICF house that they were lied to.

Do you know anyone living in an ICF house that has the ability to do a properly controlled comparison to equivalent R and infiltration value stick framing?

Most people living in an ICF house are living in the best performing house they've EVER lived in, and don't have a good basis for comparison with other higher-than-code thermal performance buildings. Moving from a typical  2x4 ~R10 whole-wall stick built that leaks 8-12ACH/50 into a 3ACH/50 R22 ICF there would be significant boost in comfort- it might feel like a palace to some.

ICF has a nice solid feel, they're very quiet & reassuring- most people who live in 'em like 'em (as well they SHOULD), but it's another "so what"?  Most people living in  tight, code x 1.5 stick-built or SIP houses find them a lot more comfortable and preferable to than anything they've lived in previously too.

The people who were told that their R20 ICFs performed like R50 sometimes even believe that, but that performance level isn't supportable by the facts (and it's arguable they were lied to, even if the installer was a true believer.)  To be sure, very few of us have lived in a home with R50 walls, so making that comparison would be difficult.  But the same people who believed R50 might also believe that center-cavity R values of stick-built is the R value of the wall too.

An R13 (R10 whole-wall) isn't terrible, but it sure isn't as cushy as R22 whole-wall with center-mass to take the edge off the peaks, making it arguably R30ish or higher from a comfort point of view when standing next to the wall during the heating & cooling peaks, if not as measured by the utility costs.  Most people aren't doing even the most rudimentary math on any of it, nor do they understand the heat transfer aspects of the building as a whole, but they think they understand what R value is about and tend to put a lot of importance on it, even at R-values where infiltration and windows dwarf the importance of R value from an energy use point of view. You can't really "feel" R50 relative to R25 very much, but you can sure measure the difference in performance.  Similarly the difference between 1ACH/50 and 5ACH/50 has a pretty subtle distinction as felt by the occupants (unless it's underventilated and humidity is though the roof), but has a measurable performance difference in energy use.

Posted By Lbear on 14 Jan 2012 01:04 AM

Posted By FBBP on 13 Jan 2012 09:42 PM


Comparing a standard code minimum frame house to an ICF is pennywise pound fuelish. Even if the up charge is 15%. Amortize it over your mortgage and then compare it to the cost of the stick frame and the associated heating bill. In other words what is your total monthly cost? And remember, you will eventually pay off the mortgage. You will never pay off your utility bill!

Don't get me wrong, I am most likely going to build with ICF.

The problem with what you are stating is that it does not compute. On a $300k home, that 15% = $45k. I can build a tight 2x6 home, blow in R-22 in the wall (which is the same R-value of ICF), and save myself $45k. It would take 50 years to break even in utility bills. Where is the savings?

For me, I would utilize ICF based on its strength, termite resistance, fire resistance, air tightness, and when engineered correctly, its seismic resistance. The insulating value of ICF does not really win me over. I know that there are many 2x6 wood frames homes that can meet or outperform an ICF home in regards to R value. What I also do know is that in a high wind situation or storm, I would rather be in an ICF home than a wood framed home.

Going into this, I know I will never see a ROI for ICF.

To be comparable on steady-state R value with an R22 ICF you'd need R8 or so.

By itself 2x6 framing with standard sheathings, sidings, interiors won't beat R15 even if dense-packed,  and R14 would be more typical.

To be comparable to an R22 ICF in comfort & utility costs depends on climate you'd have to make it at least ~R12 of exterior foam. (And in a cooling dominated climate foil faced goods with a rainscreen gap between the foil and the siding will help.)  That's still nothing like a 15% cost adder though.

But it has lower structural capacity, is a bit less quiet (though still quieter than code min in places where R13 batts 7ACH/50 meets code-min).

Building with ICF has nothing to do with ROI- it's rarely the cost/performance leader from a net-present-value on future utility cost saving point of view, but they're comfortable & quiet, and generally low-maintenance. 

In any new construction there can be good financial-analysis for going significantly better than code-min though, especially at the current low cost of money.

This may help in terms of the roof system www.facebook.com/onevollc