I would not describe ICF as
I would not describe ICF as inorganic as it consists mostly of organic expanded polystyrene. Materials such as AAC or cellular lightweight concrete (CLC) are totally inorganic and cannot burn. They are also strong, quiet, air tight and have a good thermal mass. Companies such as Greentec Construction Technologies (https://greentecct.com/) offer molds and equipment for producing CLC products such as blocks and panels.

As we continue the debates on
As we continue the debates on this and that someone anyone should look up and see what is really going on. Material usage has changed and all past arguments have made a 180 and nobody seems to have noticed.

Composite Sandwich Core Construction changes how we can and should build homes to meet our goals for the implementation of producing Net Zero Structures to meet more sustainable demands on the industry. Using Insulation for Framing and Insulating in one product saving both time and money, who knew.

I’m confused.

How do you equate payback in terms of years when you haven’t expressed the GWP in terms of MMBTU’s?

Thomas, I have heard a lot of

Thomas, I have heard a lot of ways to present the insulation/air sealing concept but what you have posted here is brilliant. Thanks for sharing.

As a builder, when I start the conversation with new clients regarding energy efficiency and insulation, I always educate them on the three ways heat energy transfers in and out of a structure (conduction, convection, radiation). All three need to be considered and addressed in some manner. The key is to determine which one(s) will give the greatest return and thus deserve extra attention. The first dollar that I spend is on convection because if I cannot control air movement in and out of the structure, everything else is a waste of money. So, the first inch of spray foam delivers the greatest bang for the buck. Convection issues in the structure itself are stopped dead. Once that is done, I can move on to conduction and radiation. Adding additional insulation as appropriate with either fiberglass or more inches of foam becomes more of a cost based decision. (Note: Closed cell foam is awesome for increasing structural integrity as an extra benefit). Lastly, as we are in Coastal NC with a lot of summer heat gain, I use either standing seam metal roofing or some form of reflective barrier under the roof to reduce the effects of radiant heat. Above and beyond, I never build stick frame construction due to all of the inherent weaknesses structurally and energy wise. Starting in 2010, I only build using a precast insulated concrete wall system from Superior Walls of America. My houses are build like a boat, sealed tight, and can resist damage from hurricanes, tornadoes, wildfires, earthquakes and floods. I haven’t however, come up with a solution for Florida sinkholes.

An insulation topic for a future article. The typical R-value for polyisocyanurate foam is R6 per inch. I’ve seen articles that say because of off gassing the aged value of it is down around R5.4 per inch, even for foil faced foam. And also that in cold temperatures this type of foam performs even worst.

We recently had an Insulated Metal Panel (IMP) sales rep at our office claiming their product is R8 per inch. It’s got a metal outer skin on both sides and polyisocyanurate foam in the core. I’ve been challenging her on these claims in emails back and forth. Every concern I raise gets an answer. I appreciate the company responsiveness but my mind still doesn’t want to accept the results.

I asked for any laboratory tests of their product. I get one from an independent lab of one of their 6″ wall panels. It was two parts with the panels secured together with their typical steel clips and butyl sealant. So this test included a seam in the panel system. Total surface area of 40 sf. Warm side at 69.8 F and cold side at -0.2 F. Even a wind of 15.6 mph on the cold side. Test duration of 4 hours. The measured thermal resistance for this 6″ panel system was 48.92 (hr)(ft2)(F)/Btu. Adding the skin effect they got 50.15.

I’ve asked for any testing of aged panels but they don’t have any tests like this. I’ve search the web and can’t find any data on aged panels either.

What am I missing? What should I ask or demand? Can the 26 gage steel skins prevent all degradation of the foams R-value as they claim?

I also agree with the comments on impacts of air sealing and moisture management outside of insulation studies.
A couple of comments on both your text and graphics. The diminishing return in heat flow is the only guaranteed graph – the payback graphs ASSUME certain costs (both initial installation of insulation and heating); if the install cost goes down payback speeds up or if heating costs increase payback speeds up. The insulation R values you talk to are NOT the wall/ceiling average R values, just the insulated cavity (or exterior sheathing) so this graph does not take into account the increased average wall/ceiling R value due to reduced thermal bridges using exterior insulation. In any of the zone recommendations there is always an inherent number that is not so evident to most observers – comfort set points for the PHIUS heat gain/loss and cost/payback for most other recommendations. It does not take into account that insulation material (for the most part) is one of the cheapest building materials used in construction – it is the labor that is much more expensive. So adding additional insulation at the onset incurs a minimal cost overage – especially if future costs of heating/cooling (or different comfort desires) would dictate additional insulation (at additional future labor costs).

All good points, Paul. You

All good points, Paul. You touched on what I think is the most fundamental issue of all: growth. Becoming more efficient with energy is great, but all it does really is buy some time. The global economy is based on the premise that it must keep growing. When we can adjust our thinking and figure out how to get to a steady state economy, we’ll be on the way to finding a real solution. Can we solve the climate crisis with continued growth? I don’t know but it seems doubtful.

Here’s an article I wrote a few years ago about the topic:

The End of Growth – Mathematics & Peak Oil

http://www.energyvanguard.com/blog-building-science-HERS-BPI/bid/29920/The-End-of-Growth-Mathematics-Peak-Oil

Great discussion.

It bears repeating though that the connection of reducing global warming through efficiency improvements of any kind is tenuous at best. The only real ‘solution’ to limiting global warming is to keep fossil carbon fuels in the ground permanently. The prime driver of global warming is consumption due to affluence derived from fossil fuel use. Large houses with many bump-outs don’t help.

No permanent mitigation will be achieved unless efficiency improvements achieve cost-savings that can *only* be spent within an economy that guarantees steady reductions in whole-economy carbon emissions. Our economies are vastly more efficient than 50 years ago but they emit more carbon in total as they are bigger. The essentially permanent and irreversible level of warming will continue to increase until net carbon emissions reach zero.

Efficiency improvement is good but it will not result in climate mitigation unless the economy acts within an enforced and annually decreasing cap on total emissions.

Working within such a capped emission pathway to zero carbon would require massively more efficiency work and energy demand reduction than hitherto envisaged. It might even employ a lot of people to get it done.

I think I echo William’s thinking. The function of insulation in our projects goes far beyond mere R-Value. That’s important in the Jax, FL high humidity zone 2 climate.

CC foam provides a vapor barrier, adds structural strength, often brings ductwork into indirectly conditioned space, and reduces infiltration.

How do those difficult-to-quantify benefits figure into the calculus?

I don’t necessarily advocate foam for walls since a decent air seal can be obtained without it and ductwork aspects don’t figure in.

Our favorite wall is ICF, which, while probably flunking for embodied energy, also has difficult-to-quantify benefits as they are strong, quiet, inorganic, essentially air tight, and confer useful thermal mass.