Originally we were planning for radiant hydronic in both our slab downstairs and in our upstairs - which has our great room, kitchen, dining & living room areas all open - to do radiant for both areas is coming in at over $25K...
We are looking at alternatives to lower the cost. Since our home is fairly open we are toying with the idea of doing the radiant in the slab for just the downstairs, then doing a different heat source just for the upstairs. We feel that the heat will tend to rise somewhat from downstairs regardless, and we might need very little heat upstairs. Some homes in the area never use the upstairs radiant. We do have some decent passive solar exposure so we will get some solar heat on sunny days.
So far we have looked into doing simple radiant water baseboards in 3 locations. We are also really interested in the idea of a ductless mini-split heat pump for the upstairs. An 18K btu unit could easily handle our heat load - plus even though we almost never need AC it could do that as well...
Decisions are still to be made - we signed our building contract yesterday with $20k budgeted for heat - if we can do radiant in-floor for that cost we will do it.
We have looked at Warmboard for the upstairs, but the $10k additional cost for just the floor boards over a standard sublfoor was to high.
We have also looked at Ecowarm, Quik Track, and they all seem a bit high per sq. ft. for what we need. Staple up was suggested but seems a bit lower in efficiency, but would be cheaper.
We were quoted $9-10 sq/ft for basic radiant hydronic in floor heat.
Total heated 2800 sq. ft. - upstairs 1200 - downstairs is 1600.
We are on the west coast in a very mild marine coastal climate. Our coldest design day is 33 deg so not a cold climate! We really need no AC at all.