We are currently in the design phase for a SFR residential project in western Washington (Seattle area). The building will be constructed of ICF with concrete floors for the basement, 1st and 2nd floors. Basement will be slab on (below) grade and the other floors will be composite steel deck with concrete slabs. Planning to use radiant for both heat AND cooling using pex imbedded in the concrete floor slabs. Current plan is for hot/chilled water to be provided by an air source heat pump (e.g. Daikin Altherma or similar). Any recommendations on HVAC Designers? Thanks.

The radiant heating should be fairly straight forward.Where you can get yourself into a whole lot of problems is in the radiant cooling.Are you planning on using the same pex for heat as cool.The biggest concern is condensation.Sophisticated controls need to be applied regarding the dewpoint. The ventilation system also needs to be carefully designed.Too much moist air brought into the space will create havoc.

Yes, I am planning on using the same tubing and I agree on the careful design. Air conditioning is only needed infrequently in Seattle and the humidity is low during the summer. Dew points during the months where cooling might be required are between the mid 40s° and lows 50s°. Also planning a HRV/ERV as part of the HVAC design.

What is the square footage of your home Operable windows, clothes dryers,showers,bathrooms and kitchens all need to be addressed. Do you have a high enough budjet for the system you are proposing.

we're doing this kind of a system right now in our shop here in maine, using an altherma. I would not call the design process "mature" for such systems, but we can help.