I am planning on building a Post and Beam kit on the Olympic Peninsula in Washington State. I will be building an insulated slab on grade and installing radiant. It will be a single-story, high-roofed home. I understand how the radiant heat will work and am doing the homework on what components we need to install. One of the topics that I am researching now is using the radiant slab for cooling. Looking at the groundwater temps around where I will be building, they are 45-55F in the area. According to my reading, that is the temp range that systems target for radiant cooling. Could I just circulate well water in the slab to achieve cooling? I imagine that it would raise the temp of that circulated water by 20, 30, 40? degrees that would then make the instant hot water heaters much more efficient. Has anyone heard of anything like this? Probably overthinking but want to avail myself of the reducing water heating costs as well as cooling costs. Thanks, John

I run all water used in our house through the floors in the summer. So If it is hot outside the grass usually needs to be watered so I turn on the tractor sprinkler. It does work for 80% of the days but it doesn't dehumidify. Run a mini split or AC the rest of the days.

High desert climatology at 44 degrees latitude. Summer temperatures can commonly hit 100 degrees F during the afternoon. At present I am cooling with a water to water heat pump and have available both hPex tubing embedded in gypcrete floors plus a duct system. So far all cooling has been by directing chilled water from the heat pump at around 45 degrees to an air handler. It works.

For this summer I am going to try circulating 65 degree water through the gypcrete floors and see what happens. Cooing will be supplemented by the chilled water air handler as needed.