I have spent a good bit of time this week working on the mechanical systems for the River House. At this point, I think we will be using two cold climate heat pumps, one for each wing of the house. This partition is essentially the night time zone (west wing) and the daytime zone (east wing) allowing for a straightforward temperature setback strategy to save energy. It also means that we will have a measure of redundancy should one unit fail. Furthermore, the east wing zone is almost entirely an open floor plan which means we can use a common return, whereas the west wing is composed entirely of individual rooms which will benefit from having a return vent in each. Locating the HVAC trunk lines is the biggest challenge and I now have a plan which I believe will work very well.