I really would like to have a single heat pump handle both domestic hot water heating and space heating/cooling.  Of course I want an air source heat pump as geothermal is far more costly.  But I'll be building in zone 5 or 6 and want to have the heat pump work even when it gets cold (below zero F).  My wife and I prefer a more or less traditional interior layout which is not really open enough for a  minisplit solution and they don't do DHW.  There are air to water multifunction heat pumps (from China) that work down to -13F (-25C) BUT. how to do the room heating and especially cooling?  I just found the "Edwards Valence"  & it looks like a valid option for both heating and cooling without a forced air system in other words all hydronic.  The system uses water to air heat exchanger(s), complete with condensate drains for cooling, located at the top of walls & hidden by a valence so convection moves the air past the 'radiator'/ chiller coil.  Has anyone here used them?   

You can get heating and cooling and DHW with a Daikin Altherma. As you are finding out, implementing the cooling strategy is a bit more problematic.

Any fan coil with a drip tray should work for cooling. Even radiant floors can work if you have a well sealed house, control air pressure (you want very slightly positive) and have an ERV/HRV system for circulating small amounts of dehumidified air (see DOAS).

Do you have a link to air->water heat pumps available in the US (60Hz power, other than Daikin)?

Jorr,
There are numerous Chineese equivalants to the Daikin Altherma (inverter driven all in one) However heat pumps that incorporate EVI can operate at lower outdoor temperatures and most of those are 50 Hz only. However there is one that incorporates both EVI and inverter and it does allow 60 Hz power. http://www.macon.com.cn/index.php?action=wareshow|macon|1|en|13464,6453|997

Happy new year everyone!

I suspect that most of the inverter heat pumps that list 50hz also work on 60hz. After all, the AC current is just being turned into DC. But a manufacturer would have to confirm this.

The big Japanese brands seem to be ignoring the US market for W->A. I guess that leaves it for China.

It might be more cost effective to use an air->air unit in a main area and then air->water for the smaller, closed door rooms.