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Old 09-14-16, 04:55 PM   #16
Apprentice EcoRenovator
Join Date: Oct 2014
Location: SE MI
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Originally Posted by stevehull View Post
Oklahoma is a mixed climate state. Here in central Oklahoma, we have more winter heating degree days than summer cooling degree days. But "winter" is only about 10 weeks long (mid December to March 1). Our first frost date is in mid November and last frost about April 1.
Actually pretty similar to a lot of the mid-west, like SE MI.

Originally Posted by stevehull View Post
The use of exterior grade foam insulation, SIPS and tight building techniques (with air to air HRV) are the plan.
Check into reclaimed polyisocyanurate insulation. Big cost saving over new and it has excellent R-value per inch.

Now I am thinking of the in floor radiant cost/benefit ratio . . .

A cheap alternative would be to put in electric resistance cables. It goes against my engineering grain to use high grade power (electricity) just for resistance heating, but maybe that is a better option.[/quote]
No, no, NO ! You will hate yourself when you get your electric bills !

Originally Posted by stevehull View Post
Like many of us, my wife and I hate cold floors - so do our dogs. We also dislike carpet and like "clean" floors.[/quote
What does a "clean floor" mean ? Burnished concrete ? Terrazzo ? Bamboo ? Traditional hardwood ?
With any radiant concrete floor you need a vapor barrier and >2" of rigid foam, first.

The first 2 would work well with PEX in the concrete. Terrazzo should be okay but it need a barrier between the concrete and the bamboo (rosin paper) to allow the flooring to expand and contract. Hardwood over concrete is a whole different conversation !

Depending on the number and size of the rooms, IMHO, you want a hybrid system. Mini-split (ductless) heat pumps that also heat the radiant heat water through a heat exchanger. You get the comfort of a heat floor with forced air, as needed, for quicker recovery and high efficiency A/C.

If you have a large number of rooms (3+ bedrooms, living room, family room, dining room, kitchen, 2+ bathrooms, etc) that do not have good "natural" air distribution, the additional air handlers and piping will kill you. At 3000+ sq ft, you will likely need 2 compressors.

Once installed and "tuned" I think you will love it and it would be very cost effective.

Mitsubishi sells system like this but not in the US.
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