In the planning stages of new residential construction to be built in zone 7 Central Arkansas.
High humidity with temps in 90 to 100 range, cost of cooling in the summer consumes more energy expense than heating for me.

Two questions :
  1. What type form is better suited for southern region; flat wall or grid; 4, 6, or 8 inch ?

  2.  Will the expense of radiant heat flooring be worth initial investment in zone 7 ?

Welcoming any and all opinions.....Thanks.........P K

my research has told me that the best icf is the one your chosen installer likes.

Worth it? Look at it this way: ICF's(or SIPS) are an upgrade over sticks. So is radiant. Radiant(IMHO) is the Cadillac of heating systems. I have it, and I won't build another house(to live in) without it. But my situation is quite different. Only heating, no A/C needed.

So that said, it's up to you. It would certainly be less expensive to use forced air. But if you value a quiet, very comfortable, heated environment, radiant might be for you.

I have used both flat wall and grid, definitely prefer the flat wall. Much easier to work with and stronger. As to thickness, 6 inch will be more than adequate in above-grade and simple basement applications. As to radiant heating, I love it, but have a hard time with the additional costs involved with the need for A/C. And you are right. A/C will account for about 70% of your annual needs. You might check out a system that Bill Chaleff describes in his articles on the SIPS side of this forum. It basically uses an underfloor forced air heating system that uses a central HVAC system.

And if your heating needs are limited, you could consider one of the high-velocity systems which provide excellent cooling. I'm not a big fan of the heat side for climates such as New england, but with one of the new variable speed blowers, you could use a water heater or one of the tankless on-demand heaters for your boiler and have a great hvac package.

By the way, H-V systems typically remove about 30% more humidity than regular forced air systems. In my own home, t-stat at 72 my humidity is usually around 44, but during a very hot spell it got down to 35(not recommending 35, just an observation), humidity levels should be 50-60 for relative comfort, lower humidity feels colder than it is!

P K
If you have a pro install your ICF then you shouldn't care what brand he uses
I woulod not use the grid systems again unless the owner paid a LARGE premium.
Think about a heat pump for you location. It is the most effecient system available for heating and cooling.
Tankless water heaters are the greatest plumbing invention since indoor plumbing but their initial cost is high. Mine cost me $1 per hour and I never run out of hot water. I have three of them in my wifes house.
I build 4" walls but do not recomend them to DIY's.
Regards,
Joe

Thermally a flat wall will perform better,than the grid wall. Because there is more surface area with all of the curves of the grids(times that by 2). Think of your concrete wall like a radiator. You could use a form with more foam on the outside to help on your cooling loads. If the additional cost of the radiant floor system is a concern, then use a Plug and play radiant floor kit. This will at least eliminate labor cost.

P K Is this a basement home? Assuming not a 6" wall is the most common width used today. As far as the wall being flat or grid that all comes back to the installer. If your the installer then I would recommend a flat wall due to ease of pouring and consolidation issues.

Dave

Examples of Concrete Pour into forms.

To: P K

Check the forum category above for your answer about whether to use flat wall or grid. I'm not perfect, and I'm not saying that it's my way or the highway, but just chew on what I said there about swiss cheese before you "pour" your money down the drain.

As far as best form for your area? Just choosing ICF in tornado alley or humid areas like yours means you've done right. What exact form? Whatever you want, like, desire. Most (95%) of form makers can deliver anywhere, for varying costs of course. And most installers can adapt to another form fairly easily. It's your subs (electricians, plumbers) that will have a wider learning curve.

And I'd go 6" or bigger, you're better off with a stronger home for whatever nature will throw at you.