ICF's or regular poured walls?

[DougWil]

4. In an imaginary scenario where stick and ICF buildings have the same R value and same air tightness, they would yield comparable thermal comfort, and the total energy use would probably be less with ICF, but it depends on climate and the ability to leverage the thermal mass of the ICF. A poor implementation could decrease comfort.

5. In a comparison based on wall thickness, ICF would have a lower R value and then a comfort and energy savings comparison would come down to R-value vs mass, which depends on climate, windows, orientation, even things like interior surface finish. It is possible for ICF to save at lower R value because in most climates much of the load swings though the balance point.

Correct but unless the building is in the southwest, the thermal mass provides little to no benefit.
http://www.greenbuildingadvisor.com/blogs/dept/musings/all-about-thermal-mass

 

[DougWil]

Doug it is clear you have no use for ICF and that is fine with me. What you are using as examples don't equate. Efficiency has to be looked at as a package not just rated R value. They way you look at it my statement it may be contradictory to you, in reality it's not. R value and efficiency are not mutual exclusive. Just because you have a lot of insulation doesn't make it efficient.

If you are going to make a comparison between 2 building systems you have to equate the quality of construction.

For example insulation values. And yes if one has lots of insulation, poorly installed and lots of air infiltration it probably won't be a winner.

But if you have equal R values, more or less equal air tightness (past a point of diminished returns, if your home is too air tight you then have to bring in fresh air), etc,, a IFC is going to cost a lot more and have much thicker walls.
So by definition, IFC "as a package" is not more energy efficient.

It does have other positive qualities, but energy efficiency isn't one of them.

 

[thejaq]

Correct but unless the building is in the southwest, the thermal mass provides little to no benefit.
http://www.greenbuildingadvisor.com/blogs/dept/musings/all-about-thermal-mass

IMO, this is too broad a conclusion from that work. Maybe fair to say it is a practical conclusion absent cost-ineffective engineering work. It is best in the desert because the swing happens everyday, but can be engineered everywhere that has load above and below the balance point, which is every non tropical climate. It just becomes more difficult to do right (easy to screw up), has less benefit, and is limited seasonally. It can work significantly​ better in coordination with other design elements. I doubt it is sincerely attempted very often, though.

 

[csp]

Since a newbie bumped an old thread with a new question but no one noticed, I'll re-post his question again so it doesn't get buried in an argument.

Actually is was noticed and answered in post #32.

I'm glad that my walkout basement was done entirely in ICFs, rather than stepped and the parts above ground stick framed as typical in walkouts. I'm not going to argue R-value, but there are most definitely noticeable differences that ICF offers that you can't place a dollar value on.

 

[wssix99]

Since a newbie bumped an old thread with a new question but no one noticed, I'll re-post his question again so it doesn't get buried in an argument.

Yes, Answered in Post #32.

 

[gnpenning]

If you are going to make a comparison between 2 building systems you have to equate the quality of construction.

For example insulation values. And yes if one has lots of insulation, poorly installed and lots of air infiltration it probably won't be a winner.

But if you have equal R values, more or less equal air tightness (past a point of diminished returns, if your home is too air tight you then have to bring in fresh air), etc,, a IFC is going to cost a lot more and have much thicker walls.
So by definition, IFC "as a package" is not more energy efficient.

It does have other positive qualities, but energy efficiency isn't one of them.

I have had 2x6 and 2x8 and ICF homes. I've paid the bills. Even though I'm heating more sq ft with ICF my heating bills are lower. For me it's more energy efficient.

 

[wssix99]

DougWil's comments about "R" are correct. The "R" value is resistance to movement of heat.

However, the mass walls also have capacity. They act like a giant "heat battery."

The combination of the Resistance (nothing special here, as DougWil points out) plus Capacity makes ICF super energy-efficient. Wooden walls can't deliver this combo. (For that matter, concrete isn't the only player in this arena. Adobe walls, stone, etc. also deliver similar effects.)

When a wall has Resistance plus Capacity, heat moves through the wall at the same speed as a wall with the same Resistance but no Capacity, but... the temperature of the wall changes much more slowly because much more heat needs to get out of it over time. (It's a "heat battery".)

On the inside of the house, the HVAC (the energy intensive thing) keeps the temperature generally constant. The wall either radiates the inside heat outward in the winter or radiates heat inward during the summer. The capacitance effect tempers the effect of the temperature changing outside the house as day turns to night and the core of the concrete wall reaches an equilibrium between the average ambient outside temperature and the inside temperature of the house. (Window glazing is a bit of a wild card here, but we'll ignore this for now. Firebrick43 has a great thread where we talked about this...)

The effect of this is that the HVAC system doesn't need to run at peak loads to keep up with peak demands caused by day/night cycles and spikes/dips in temperatures outside the house. Instead, the HVAC system runs low and slow, (like great barbecue) - less often and more consistently throughout the day. The HVAC system is much more energy efficient in this mode (vs. running at Peak AC loads during the summer days or Peak Heat loads during the winter) and this is how ICF pays off.

For example, my HVAC system is (generally - it all depends on the year's weather as to the timing) completely turned off (except for the circulation fan) from mid-April through mid-June and from mid-September through mid-November. (The heat capacity of the walls keeps the house at the average ambient temperature for the season and they radiate that temperature throughout the day.)

So:
- R Factor isn't everything.
- ICF is energy efficient because it tempers the loading on the HVAC system and allows it to run less overall and less a peak loading.

 

[gnpenning]

^^ This reminds me that I have no cooling costs during the summer. I have a covered patio on the south side and the garage is on the west side of the home. I have no direct sunlight on these windows. I open all windows at night and close them in the morning. Since the nights cool to the low to mid sixties even on the hottest days of the summer the house will cool to the same temps. During the day even when it gets to high nineties I will only have a 3-4 degree heat gain. So I go from 63 to maybe 67. No need for A/C.

 

[wssix99]

During the day even when it gets to high nineties I will only have a 3-4 degree heat gain. So I go from 63 to maybe 67. No need for A/C.

We find that managing the solar gain with shades on these days also helps a ton. The walls soak up the heat during the day and radiate it back out at night.

 

[Modern]

Yes, Answered in Post #32.

Thanks for the reply. I haven't come across any icf homes in Chicago that I know of, so I was curious about the process. My brother has an icf home in a new subdivision and its the cheapest to heat or cool compared to the other houses.

 

[DougWil]

However, the mass walls also have capacity. They act like a giant "heat battery."

The combination of the Resistance (nothing special here, as DougWil points out) plus Capacity makes ICF super energy-efficient. Wooden walls can't deliver this combo. (For that matter, concrete isn't the only player in this arena. Adobe walls, stone, etc. also deliver similar effects.)

When a wall has Resistance plus Capacity, heat moves through the wall at the same speed as a wall with the same Resistance but no Capacity, but... the temperature of the wall changes much more slowly because much more heat needs to get out of it over time. (It's a "heat battery".)

The concrete only acts as a heat battery when it stores energy from it's temperature increasing, once it has reached it's steady state temp, no additional energy is stored, but simply passes through it.
So in a cold climate, in winter, when you have high heating costs like in Chicago the outside temp is always below the interior temp and energy just flows through that 6" of concrete because it has a very low R value.

Whatever energy it has stored is released when that concrete's temp is allowed to drop. But it isn't allowed to drop or drop much because the interior temp is set.

However if you are in Phoenix and the daily temp is above the set interior temp and at night drops below, the concrete's thermal mass does retain and release heat to moderate the swings.

And the more insulation you have the less the thermal mass effect, because that concrete core is insulated from swinging temps.

 

[DougWil]

^^ This reminds me that I have no cooling costs during the summer. I have a covered patio on the south side and the garage is on the west side of the home. I have no direct sunlight on these windows. I open all windows at night and close them in the morning. Since the nights cool to the low to mid sixties even on the hottest days of the summer the house will cool to the same temps. During the day even when it gets to high nineties I will only have a 3-4 degree heat gain. So I go from 63 to maybe 67. No need for A/C.

And that is when thermal mass is most effective, when the outside temps swing above and below the desired interior temp.

 

[wssix99]

The concrete only acts as a heat battery when it stores energy from it's temperature increasing, once it has reached it's steady state temp, no additional energy is stored, but simply passes through it.
So in a cold climate, in winter, when you have high heating costs like in Chicago the outside temp is always below the interior temp and energy just flows through that 6" of concrete because it has a very low R value.

This is not correct.

The heat from the inside of the house fills up that heat battery in the winter and the rate of heat loss is slowed. There's no difference in the laws of science or performance of ICF (symmetrical blocks) between the seasons. The heat flows just reverse directions.

And the more insulation you have the less the thermal mass effect, because that concrete core is insulated from swinging temps.

This is not correct, either. (Doing a simple though experiment with this statement, you would be saying that removing all the insulation would give a more efficient wall.)

Thermal mass is thermal mass. Adding insulation around that mass, slows the inflow and outflow of heat to that mass. The charging and discharging effects on the heat battery balance out (again, for symmetrical blocks) and the net effect is a more efficient wall when insulation is added.

And that is when thermal mass is most effective, when the outside temps swing above and below the desired interior temp.

Is there a place on our rotating, tilted axis planet where the outside temps stay right at the desired interior temperature?

 

[wssix99]

Thanks for the reply. I haven't come across any icf homes in Chicago that I know of, so I was curious about the process. My brother has an icf home in a new subdivision and its the cheapest to heat or cool compared to the other houses.

There's a nucleus in the near southwest neighborhoods and a few scattered in the northern neighborhoods, but you'd never know where they are because they look like regular houses.

Since its not a common method of construction and not specifically allowed for in the City building code, people in the Department of Buildings often rotate out faster than the projects come along. So, you need a builder who can demonstrate past projects, past DOB approvals, etc. to show that the City has a track record with the construction and that City engineers have reviewed this type of project previously. (Otherwise, they could send you for tens of thousands of dollars of extra engineering, testing, plus delays.)

 

[DougWil]

This is not correct.
The heat from the inside of the house fills up that heat battery in the winter and the rate of heat loss is slowed. There's no difference in the laws of science or performance of ICF (symmetrical blocks) between the seasons. The heat flows just reverse directions.

Only you are not accounting for the inhabitants of the house not willing to let the interior temp swing all over the place.
Instead the interior temp is kept more or less constant through winter. Heat flows through the insulation warming the concrete. Once the concrete has reached it's stable temp it no longer stores additional heat, it just passes through.
If it is colder outside, the furnace increases output, the interior temp stays the same, and more or less so does the concrete in between the two.

Only when you have outside daily temp swings above and below the desired interior temp can the stored heat be effectively utilized. And that doesn't occur in cold climates unless you are willing to live in a home with an interior about mid point between outside highs and lows. Say 30 degrees with frozen pipes.

This is not correct, either. (Doing a simple though experiment with this statement, you would be saying that removing all the insulation would give a more efficient wall.)

No increasing insulation decreases the positive effects of thermal mass.
An uninsulated adobe home in the SW is vastly superior to an uninsulated low mass home. That is why it was used.
But the more insulation the less the effective that mass becomes.
It is called diminishing returns.
As a thought experiment, if you had a super insulated home with zero heat loss, would adding mass help?
Answer, no because that mass is always at a stable temp and never stores additional heat or releases it.

Additionally, the most effective place for the mass is a bare interior wall, but with IFC it is under interior insulation.

 

[73RR]

...what I'm curious about is why a guy in Portland even cares about ICF construction...
Portland rarely gets below 32 or over 90...averages of course.....

Someone once said something to the effect that you can have your own opinion but you can't have your own facts and the facts are that ICF construction saves huge money on heating and cooling. Period.
The additional benefits of sound control and stopping .50 Cal rounds is just a plus....

Yes, ICF costs more than other methods of construction and unless you are in the building for ten years then you are probable better off with sticks and nails...unless you are dealing with high winds like a tornado and want a safe place to hide, or if you are in a noisy environment, or if you want to keep the termites out, or.......

 

[gtae07]

Ok, so I have an ICF question... is a basement a requirement for an ICF building? I've been looking at ICF house plans and every single one is standard for a basement, with apparently no other options. Is there no slab or even crawlspace option?

 

[MushCreek]

Of course an ICF house can be built on a slab. It's just concrete walls, after all, and FL has millions of concrete homes built on slabs. If you're in a colder climate, though, make sure the slab is properly insulated, or you're throwing away the benefits of an energy-efficient house. A house doesn't have to be specifically designed for ICF, either. Most designs will translate, although you may waste some materials, and run into clearance issues with the thick walls. I designed my own house around standard ICF dimensions for the brand I used. Inspection was no problem, as ICF is considered 'prescriptive' here as long as you follow the manufacturer's guidelines. Actually, the inspector didn't even look at the ICF detailing, except for to comment that it looked 'really, really strong'.

ICF is not ideal in all climates. I don't think there is any one method that is best. Where we are, temperatures are reasonable much of the year, but we often get big swings- 40 degrees or more. If I lived in a climate that was really hot or really cold much of the time, I'd build with steel skinned SIP's. Little to no thermal bridging, and all of the insulation you want (or can afford). I was going to use them for this house, but I had no way to erect them alone, and the guy doing my site work builds ICF exclusively, and helped me a lot.

You can certainly build a tight, well-insulated home out of conventional framing. I'd be curious to see how much air leakage increases over the years, though, as the wood warps, shrinks, splits, etc. Probably not enough to matter, but still.

 

[gnpenning]

As mentioned you will need a footing and foundation to match the weight of the wall. The depth will need to meet local building codes.

With those things met you can build ICF without a basement.

 

[73RR]

Yup, I've got two of them on a FPSF.

gtae07, I'll suggest that you ask around for someone who has ICF experience for some help/guidance to help design a slab based on your local codes.

 

[wssix99]

Once the concrete has reached it's stable temp it no longer stores additional heat, it just passes through.
If it is colder outside, the furnace increases output, the interior temp stays the same, and more or less so does the concrete in between the two.

You are still making the assumption here that the outside temperature is constant - but its not. If both the inside and outside temperature were constant, everything would equalize and what goes in would equal what goes out. But since the temperature outside is changing, so does the thermodynamic potential and the heat battery keeps working. (With the heat battery at work - ICF outperforms a conventional wood framed wall.)

It doesn't matter if the heat source is constant (as in the interior temperature in the winter) or variable (as in the exterior temperature in the summer). As long as there is a thermodynamic potential on one side of the wall or another, the thermal mass will go to work.

Indeed - more heat is lost during the winter than is gained in the summer months, but it's not because of the construction of the ICF wall. (The same goes for any type of construction.) The thermodynamic potentials between a 68 degree house and a 10 degree outside temperature in the winter are much greater than the potentials between the 72 degree house and 90 degree outside temperature in the summer.

No increasing insulation decreases the positive effects of thermal mass.
An uninsulated adobe home in the SW is vastly superior to an uninsulated low mass home. That is why it was used.
But the more insulation the less the effective that mass becomes.
It is called diminishing returns.

If your statement is referring to the postive financial effects of thermal mass, I would concur. Aside form that, Mass is Mass. The insulation doesn't hide it from the universe or change it's physical properties in any way. That extra insulation just delays the time it takes the heat to get to from the surface, through the insulation media, and to the mass. Once the heat is at the mass, the mass treats it no differently than it would at any other time.

There are definitely diminishing financial returns to the insulation thickness. My next statement is not backed by any specific evidence, but my experience with the means and methods of ICF construction would lead me to believe that the foam thickness is specified more for the stability of the unit as a concrete form than for its insulating value. (The R value of an ICF wall is typically much higher than would be required of a comparable stick-built house.)

The extra foam needed for the form work is there in the end, even if the last inch isn't as economically valuable as the inner 1.5 inches.

As a thought experiment, if you had a super insulated home with zero heat loss, would adding mass help?
Answer, no because that mass is always at a stable temp and never stores additional heat or releases it.

There's no perfect insulator, so that's why we contemplate and utilize mass walls for energy efficiency. If I could actually get a mythical perfect insulator and super-insulate a house that way - I would use that.

Additionally, the most effective place for the mass is a bare interior wall, but with IFC it is under interior insulation.

This is a problem for the PhD's... My understanding from talking to engineers who have pursued this academically (and run the thermodynamic math calculations against ambient conditions) is that there are some parts of the world where it makes sense to insulate only one side or the other of a mass wall, where there is either a single heating or cooling season - but not both. My understanding is that in climates where there are both heating and cooling HVAC seasons the math works out favorably to insulate both sides.

 

[wssix99]

BTW - If I was to do this all over again, I'd still go with the sandwich mass wall with insulation either side - but I would explore tilt up construction instead.

My expectation is that in a vertical urban environment, the construction costs would have been lower. (To DougWil's point about the diminishing returns of foam insulation) I would have also been able to optimize the inside and outside insulation thicknesses for my local ambient temperatures. (A foam center may have also been an option.)

 

[DougWil]

You are still making the assumption here that the outside temperature is constant - but its not. If both the inside and outside temperature were constant, everything would equalize and what goes in would equal what goes out. But since the temperature outside is changing, so does the thermodynamic potential and the heat battery keeps working. (With the heat battery at work - ICF outperforms a conventional wood framed wall.)

It doesn't matter if the heat source is constant (as in the interior temperature in the winter) or variable (as in the exterior temperature in the summer). As long as there is a thermodynamic potential on one side of the wall or another, the thermal mass will go to work.

Only a thick layer of insulation dampens the temperature swings of that mass.
Because it loses heat slower, when the outside temp is low, the mass temperature doesn't drop as much, hence it will not recharge as much when the outside temp rises.

That is why the more insulation you have the less effective the mass.

This has been studied by Oak Ridge Laboratories in the 80s and has been backed up by other studies.

In the classic thermal mass scenario — a hot-climate house with uninsulated adobe walls — a high-mass wall can provide thermal benefits. But what happens in a cold climate during the winter?

If daytime highs are 50°F or less for months at a time — as they are in colder areas of the U.S. during the winter — thermal mass won’t help much. After all, heat is flowing through your walls in just one direction: from the interior to the exterior. Under these condition of steady-state heat flow, you need insulation more than you need thermal mass.

Studies have shown that thermal mass can provide heating energy savings in only a few areas of the country. “The sunny Southwest, particularly high-elevation areas of Arizona, New Mexico and Colorado, benefit the most from the mass effect for heating,” Alex Wilson has written. “In northern climates, when the temperature during a 24-hour period in winter is always well below the indoor temperature, the mass effect offers almost no benefit, and the mass-enhanced R-value is nearly identical to the steady-state R-value.”

http://www.greenbuildingadvisor.com/blogs/dept/musings/all-about-thermal-mass#ixzz4eAsw06pB

As far as IFC performing better than wood framed, where and what are you comparing?

Certainly not in cost, and certainly not in wall thickness.
What other standard would you use to make the comparison?

Someone once said something to the effect that you can have your own opinion but you can't have your own facts and the facts are that ICF construction saves huge money on heating and cooling.

I have linked articles with attached documentation. You have provided nothing but your opinion.
Which is OK, but don't pretend it is a fact.

 

[gtae07]

Of course an ICF house can be built on a slab. It's just concrete walls, after all, and FL has millions of concrete homes built on slabs. If you're in a colder climate, though, make sure the slab is properly insulated, or you're throwing away the benefits of an energy-efficient house. ...

ICF is not ideal in all climates. I don't think there is any one method that is best. Where we are, temperatures are reasonable much of the year, but we often get big swings- 40 degrees or more.

I figured it had to be possible, I just kept running across everything stating "basement" as foundation and talking about basements and figured maybe there was something I was missing? I do airplanes for a living, not houses...

No worries about a "colder climate" here--coastal Georgia is a pretty warm place most of the year; a cold winter day is highs in the 40s. Our average high at the coldest part of the year is about 60. But, we get the big temperature swings (I've seen 30 degrees in one day, and 40+ over two or three days) fall, winter, and spring. The bigger attraction for me, though, is hurricane/weather resistance. I built my shop to the latest hurricane wind codes and it still doesn't give me the warm fuzzies like a concrete and rebar wall would.

 

[ssdave]

If you're looking at ICF for hurricane/tornado/wind/weather resistance, remember that it is just one part of the equation. The weak points on most houses are:
1) Garage door
2) Roof gable ends
3) Doors, windows, openings
4) Roof sheathing
5) Continuity of load path from roof to foundation.

An ICF takes out the continuity of load path and makes the walls strong. It also adds mass to the overall structure so it has global stability.

To take full advantage of the benefits of stronger walls and heavier mass, you have to beef up the other things.

The roof has to be fully anchored to the concrete walls. Good anchors, and good attachment of roof trusses to the top plates that are anchored. Then, the sheathing has to be well nailed to the trusses, and the end gables braced.

The garage door is arguably the weakest point, and allows winds to get under the roof to take advantage of roof weaknesses. An extreme effort to make a wind resistant door is needed, and that is expensive.

High strength doors, and a good window shuttering system is essential as a final step.

Then, you have to worry about water damage also. Window protection helps. Good shingles and underlayment, well attached will help. You may still have damage.

ICF is a good material, just not a magic bullet. It is also expensive. A safe room to help you survive and investment in good insurance might be a better storm/weather protection strategy.

 

[wssix99]

I figured it had to be possible, I just kept running across everything stating "basement" as foundation and talking about basements and figured maybe there was something I was missing? I do airplanes for a living, not houses...

No worries about a "colder climate" here--coastal Georgia is a pretty warm place most of the year; a cold winter day is highs in the 40s. Our average high at the coldest part of the year is about 60. But, we get the big temperature swings (I've seen 30 degrees in one day, and 40+ over two or three days) fall, winter, and spring. The bigger attraction for me, though, is hurricane/weather resistance. I built my shop to the latest hurricane wind codes and it still doesn't give me the warm fuzzies like a concrete and rebar wall would.

The house I posted above has no basement.

Before our windows were installed, my wife and I were moving some roof trusses around (to adjust for a chimney we forgot about) during an 80 mph (gusts) wind storm. We couldn't feel a thing while the stick frame rental we were living in was making us sea sick, it was moving around so much.

 

[wssix99]

As far as IFC performing better than wood framed, where and what are you comparing?

Certainly not in cost, and certainly not in wall thickness.
What other standard would you use to make the comparison?

A structurally equivalent ICF wall outperforms wood framed walls in energy efficiency in most human-inhabited environments on the planet earth. (A structurally equivalent ICF wall will come with a higher R value, the thermal mass, and a lot of other goodies - and that's just part of the deal.) It's impossible to make an apples-to-apples comparison between the two because a much more massive assembly is required for an ICF wall to hold up the same roof that a wood frame wall does.

An ICF wall all so outperforms a wood framed wall of an equivalent R value due to the thermal mass. Even if that thermal mass is less beneficial in the North American winter than in the North American summer, there is still an incremental improvement in efficiency.

If one lives in the structure long enough to get a financial pay-back, then the ICF outperforms in cost. If not, then it doesn't. My research has found that most ICF houses have at least a 10-15 year payback. Some are double that.

If anyone is really hung up on wall thickness as a meaningful measure, than I don't know what to say. House cats love thick window sills.... (The hypothetical conversation about making an equivalent thickness, air tight, wood wall to an ICF wall is not too productive because the only place that's actually ever been done has been in a laboratory and such an assembly would also become more expensive than ICF.)

This has been studied by Oak Ridge Laboratories in the 80s and has been backed up by other studies.

http://www.greenbuildingadvisor.com/blogs/dept/musings/all-about-thermal-mass#ixzz4eAsw06pB

We went through the all the Green Building Advisor stuff and the Oak Ridge Lab studies before we built. We even used some PCA models built off of the Oak Ridge research to do our HVAC calculations, which came out spot-on. (Code still required that we over spec/build the system, but that's another thread.)

The Green Building articles are extremely over-simplified and written for lay persons. The conclusions discussed in this article are the same you are describing and the same I am describing. The science of how one gets there is complicated and beyond what the article discusses.

An assertion that thermal mass is somehow effected by how it's wrapped with another medium (like insulation) is not correct. Mass is mass and it's physics are constant. There are strategies for layering insulation around a mass to take advantage of different ambient conditions in different parts of the country, but the article above just breaks the surface of a very complex topic and doesn't go anywhere near the science behind it nor a complete discussion of how the strategies would be employed in different areas around North America.

 

[MushCreek]

Look to FL for good garage doors. We had to install a monster in our house in central FL when we lived there. Massive beams, double hinges, and lots of good attachment to a strong sub-frame. We used to joke that in the event of a storm, we were to gather behind the garage door. They also make a system for bracing garage doors for hurricanes that you put in place prior to the storm- not much good in a tornado.

After living in FL for over 30 years, I became a bit hypersensitive about high winds- that's one of the reasons I built ICF. I also specified stronger roof trusses than standard for the area, and used the biggest hurricane clips that Simpson makes. I used heavier roof sheathing, and nailed it to FL specs. Other than the odd tornado, we don't get really high winds here, but I like stuff built strong.

 

[walrus]

I remember seeing ICF foundations in Maine but thats stopped or doesn't get as much publicity as it used to. Thermal mass would be better if all the insulation was on the outside. You could use that mass in a passive solar house. Heat it up during day let it give up that heat at night.
What about critters in the foam for you folks down in the south?

 

[Red05GT]

We used ICFs and SIPs when we built our current home 18 yrs ago. There were a couple
of factors that pushed us toward using them. We wanted a 9' basement wall and poured
contractors wanted a 50-75 percent upcharge for the extra foot! A couple of family members have mold allergies and didn't want a basement and I felt a drier finished basement would circumvent that issue. Also by using the ICF we were able to use DRYVIT
or synthetic stucco directly on the interior for a finished wall product. Since we were building the house ourselves we were able to stack the blocks very easily and reuse the
plate boards on top of the footers and the bracing boards throughout the rest of the framing project. We did change the concrete mix and specified 4000# mix, pea gravel
aggregate and fiber. We had to cut an extra hole thru the foundation a few weeks later,
and this gave us great confidence in strength of system. We used a water based waterproofing system outside the wall so as not to melt the Styrofoam, not crazy about
that but have had no issues. I would use the dimple drainage matt if I had it to do over.
We used proper footer drainage and then backfilled to within a foot of finished grade
using peagravel. I would use ICFs again in a heartbeat.

 

[MushCreek]

ICF can get critters in it. There are documented cases of termites tunneling significant distances to reach wood elsewhere in the structure. In our house, they would have to get through gravel, dimple board, peel 'n stick waterproofing, and 10' of foam to reach the wooden roof structure. Even so, we still had the ground treated, and have an annual termite contract. Our area is rated 'extreme' for termites- Yet another reason to use something other than wood for a structure.

 

[wssix99]

Thermal mass would be better if all the insulation was on the outside. You could use that mass in a passive solar house. Heat it up during day let it give up that heat at night.

This is where one can take different approaches with the construction of the heat battery. Thicker foam or eliminating foam on one side of the mass changes how it performs and reacts under different conditions. A passive house in a given area would have different needs/considerations/strategies than a house using mechanical heating and cooling in another area.

 

[73RR]

I have linked articles with attached documentation. You have provided nothing but your opinion.
Which is OK, but don't pretend it is a fact.

It is good that you are well versed in the academic version of construction but the 'facts' of the savings on heating and cooling show up every month when you pay the utility bills. If you do not build ICF structures or live in an ICF structure you will likely never fully grasp the benefits.