Bruce, I've studied ORNL's numbers; I am a fan of DBMS and am in fact building a high mass house in south central Pa. Being prisoners of our own experience to some degree, my vote for traditional ICF is predicated on how much I am giving up in R value to get that mass. (R10 in AAC construction.) I am betting that passive solar will make up the difference. Outside of the Southwest, assuming some tradeoff between mass and insulation, it gets a lot easier to choose 4 inches of foam in conventional ICF.

Donnerwetter, no drywall in AAC construction; greatly simplified stucco, or just slap on paint. All-in costs comparable to the price of ICF forms alone. Much more fault tolerant as DIY. No free energy, though, unless you count what falls from the sky around here (but, alas, not cut and split and stacked in cords.)

Radiant walls make all the sense in the world. Radiant energy travels from hot to cold. Hot air rises, but not radiant energy, unless the upper surfaces are colder than the lower surfaces. If heat only rises, the Earth would have to sit on TOP of the sun in order to stay warm, no? :-) Think of radiant energy as the beam emitting from a flash light. The bigger the shadow your body projects, the more radiant energy you are absorbing, the more comfortable you are for a given air temperature. So the beam emitted from the floor or ceiling projects a relatively small shadow, compared to the shadow when the beam comes from the side (wall). Significantly MORE energy being intercepted by the body. I did one of the first radiant wall projects here in Colorado for a Habitat for Humanity home that was sponsored by the National Renewable Energy Laboratory. It was rated as one of the highest rated energy conserving homes at the time it was built. It is also one of the most comfortable homes I've ever been in, and I've been in a LOT of radiant heated homes. For those of you contractors who poo poo the use of radiant walls, you are missing out on an opportunity to deliver extreme "comfort" to your clients. Not just "heat", but comfort, and there is a BIG difference. As my friend Robert Bean says, we need to condition the building to the occupants, not to the occupants to the building. My definition of comfort is not being aware of your surroundings. you're not hot, and you're not cold, and you don't hear any sounds in the background. You are simply comfortable, and radiant walls can deliver excellent comfort, in both the heating and cooling modes. People get addicted to radiant floors. Delivering radiant warmth and comfort doesn't have to be delivered from the floor. Provided that you raise the MRT (Mean Radiant Temperature) within the space, the occupants will actually be more comfortable at a LOWER air temperature. I'd recommend anyone associated with delivering comfort go to www.healthyheating.com and get educated about radiant COMFORT. Radiant walls also hold an excellent potential for delivering radiant cooling with little energy consumption. Check out http://www.corvidwall.com/ These guys have been working with radiant walls for two years and have about as much experience as anyone out there. They operate with very low water temperatures making them ideal for green energy sources, like solar, GSHP etc. Isolated thermal mass at its best. We need to start rethinking the way we keep people comfortable in their retirement homes, and it does not have to come from the floors. As was pointed out by another poster, the installed cost of radiant walls is less than radiant floors because there is less space to have to cover to deliver comfort in these super insulated homes. Lastly, with radiant walls, the consumer can put down what ever thickness of pad and carpet they want to use without affecting the output of the radiant panel. Think outside the box... ME

I grew up in Europe with radiators underneath the windows. Yes, the comfort level is not comparable to a standard forced air system. Back then I was a young boy and did not "care" about comfort levels because I was quite cozy underneath my duvet with the window open. Being older now it matters when you get up and are freezing because the inside air is cold (that's an individual parameter) or the floor you step on is cold. So, therfore I agree with radiant heat from a vertical position or inside the walls.

People on this thread have suggested to take off the interior insulation with an in-wall radiant system. In my humble opinion not a wise decision. If you leave the insulation in place, meaning leaving the ICF alone, and are putting pipes inside the wall, you then have created a situation whereby you have an effective thermoregulation to infiniti. No heat will escape from the inside!

Thinking outside the box is what drives new products and inventions!

Passive solar through frosted glass. Every solid in the room will be radiating heat after sundown. Free heat. But once again, passive solar high mass is a no-brainer in the Southwest; not so much elsewhere.
No offense, Mark, but the first priority these days should be keeping retirees in their homes, and TMass is a poor start on the road to affordability.

Thermal mass is the perfect road to affordability. Take the same concrete and insulation as an ICF but install it with the concrete interior and all the insulation exterior and you have a far better system than an ICF.

Manfred
As I contemplate your thoughts on "effective thermoregulation to infiniti" it would appear that once the core is stabilized, a minimal amount of interior heat would be necessary?

As the themal mass would be constant in this instance, it seems that you would have limited interior dispersion thru the insulating interior face of the wall, severely limiting the available heat?

So the perimeter is now heated, losing half to the outside face of the concrete, and half to the inside face of concrete, to me you are losing half when instead you could install the radiant on the interior face of the ICF, then apply an appropriate cover.

Yes, jmagill, T-Mass is great in theory. But when I looked at it, and dismissed it in about five seconds flat, it meant trucking precast great distances, or paying custom prices for cast-in-place to a skeptical crew with zero experience.
I realize I am a lonely voice here for cost effective construction. In fact, bbicf obviously has a client who can pay for radiant in walls, which will make excellent cocktail chatter, so why not?

You have to explain what you mean by costs effective.

For me that would be a payback of ten years or less on money spent. I know that can be done today with ICF products all ready on market, but used in a new way.

If you are going top talk bang for the buck right now this minute then SIPs will beat ICF's every single day. Combine a slab floor with SIP walls and you will have both Insulation and Mass.

ICF used in the traditional sense will not beat either of these., in cost or payback.

Jim, right you are with your assessment of core stability in general. Concrete, as we all know, cannot hold heat or cold and needs to be fed continously with the temperature you want the concrete to be. With the temperature being supplied via solar collectors on the roof and the energy stored in a sand tank underneath the house or beside the house (underneath the garage or the swimming pool) you have enough temperature energy to pass through these walls form day to day and week to week basis. The is a fluid system that needs to get charged on an on-going basis by our sun.

I have gone into some detail about this system in "crawl space or not" if you are interested in reading up on the concept. I am not saying this is the be-all end-all system but I know for a fact it is working in Siberia and Africa with the expected success.

Can in wall radiant heat be done somewhat cost effectively? Or is it a premium comfort upgrade. I'm thinking it could be used w/ a shotcrete panel system pretty neatly. something like metrockscip w/ eps and wire mesh panels.

Jmagill, by cost effective I mean that I am likely to recover my construction expenses even in an untimely sale, upkeep is modest and inflation is unlikely to outstrip my ability to pay. More specifically I chose AAC as a DIY project for my adaptation of a Frank Lloyd Wright Usonian design. What's cost effective for you, for your design on your building site, will be different.
In fact, building technology plays a minor role in my view. Given a small enough house, not much is going to generate an impressive payback. On the resale side, DIY is the only reliable way my heirs would recover my construction costs in the short term. Longer term.... Hey, this is America. The kids move away. The parents move away. The kids move back. Sad to say, you don't want more sunk costs than the resale market will bear.
So that's my personal building code. I can do it myself. It's worth doing. Others will appreciate it. Or at least not laugh. (He paid WHAT to ship radiant, tilt-up walls from Iowa?)

I have two concerns with radiant walls, comfort and useability.

We love our radiant floors, they keep our feet warm and our heads cooler. I work in an office with overhead radiant heating. I hate it! My feet are cold and my head get foggy with the heat radiating down on me.

The second would be using the walls for art etc. Those tubes could be easily damaged.

I agree that wall and ceiling radiant would work better for cooling but I am not sure that the  comfort would compare to floor radiant.

Rich, I have to agree with jmagill on the possibility of the tubes, as described by your install, to be damaged if one unconcerned/unknowing "re-sale" homeowner would put in a nail to hang a picture.

Jmagill, I hear you regarding your feet and your head. Again, thinking outside the box, what if the floors, walls and ceilings would reach a defined temperature and maintained that temperature? Heating and cooling would be a non-issue because the volume of air inside the space of the room/house would be at a constant.

Eventually you will have to exchange the air, yes? What if this could be done on an on-going basis without creating a draft issue at a rate of lets say 14 times a day? Of course the air needs exchanging in the African summer or the Siberian winter. If the walls and the floors and the ceilings are in a constant temperature state, you only have to worry about the temperature of the air, yes? What if there is a way to achieve this at no extra cost in an ongoing way, year round, winter or summer, freezing cold or blistering hot? What if you could have a system that is designed in a way that every room, not every floor, but every room on the same floor was its own zone?

First I would have to see all the details and the mechanics of the system. Then I would have to balance the costs of installing and running the system with the costs of other systems. I can already zone any room on any floor so I don't see that a selling point.

man, jmagill, you are cold hearted, eh!? Zoning every room is not an issue for you but it is an issue for just about everyone else. The cost of this system is coming in at about 25K. Running it will be at about $15 per month.

The details are not ready for the public yet as they are very technical and are perused by American engineers. The mechanics of the system will be disclosed in the near future, as they are very straight forward.

Good disscussion guys, I am the builder/homeowner/contractor that this thread is based around. I would like to clarify a few points to keep the replies valid.

1. I would like to install ground loops around my weeping tile and in my back yard while I have the excavation being done. I don't see this being a big cost, as I will be doing it.
2. I plan on transfering this energy to the middle of the concrete in the ICF on the portion of my walls that are exposed to the ambient. Ambient here is +100F to -40F
3. I do not plan on heating with this geo source just trying to utilize the stable temperatures in the earth to stabilize my wall mass. If my wife would let me build underground I likely would consider it. So I will bring the ground to my walls.
4. The way I see it, i will only be out the enegy of a circulating pump, and if the dT isn't there the pump wouldn't run.
4. ICF insulation at 2.625" on either side will stay as it is
5. I believe the cooling function on the south exposed wall will be valuable.
6. Heating will be performed by mod/con topping up solar fed storage tanks and distributed through low temp hydronic in basement, warmboard upstairs and the garage slab
7. Other things that we are going try, heat exchanger on the municiple supply for chilled water, drain heat recovery, vestibule, and sun room to isolate our exterior doors in the cold winters, solar mass in the sunroom floor, exposed concrete pillars from basement to ceiling with hydrionic in them to assist with heating and cooling, auto roll shutters, proper roof overhang for shading, solar light tubes with thermal break.


We built a full ICF house 4 years ago with floor hydronic heat, we relly like it but see some obvious improvements we could make. It was a 1433sq/ft bungalow.

Money, I enjoyed the comments about the cash I must have. I understand if I asked a homebuilder to build this house they would likely say no, and if one did take it on it would cost a mint. Each item I am proposing is not expensive. I have to put the plan together and must make it happen. No contractor wants to spend the time around this area, just get you duraforms up, pour and there you go. Many concrete basements are not even insulated.

Dan Field