Hi gary - Several of the outfits installing solar water heating systems around here have told me that the cost of installing a system that also uses solar heated water in a radiant heat system is too high to be viable; i.e. normal solar hot water systems won't produce enough hot water for radiant heating, especially at night, so that you'd need to quadruple the collector area and storage capacity to run both systems. One guy told me that even if I tried to minimize my usage thru efficient zoning, the cost of the equipment is so muich greater that I'd still be better off reinstalling my forced air system run on natural gas. Any ideas?

Have you contacted a rep fromÂWarmboardÂ? I think your home would be more comfortable with radiant in-floor heating. You will probably remain comfortable at a lower temperature with the radiant in-floor heating and youÂll have greater resale value. SR

The most efficient way to heat your radiant in-floor and domestic hot water is with a water-to-water geothermal heat pump. If you would also like air-conditioning too, use a triple function geothermal heat pump; full capacity hot water for radiant in floor and domestic hot water as well as forced air for both heating & cooling. Divide your electrical rate by the COP of the GSHP to determine the cost per kW. ItÂs usually a factor of 3.5~5. Geothermal has the highest initial cost but the money goes directly into the value of your home. Geo also has the lowest operating & lifecycle cost and highest user satisfaction rate. Did I mention GREEN? After opening the link below, click 'Products' then click 'TR-Series', then download the R410a Models pdf. SR Here is a link that might be useful: Nordic Triple Function Series GSHP

This is a question for the person designing your heating system.