We installed a ducted heat pump in December, using the existing ducting ( in an unheated basement) that was installed 20 years ago for an oil-fired boiler and central air conditioner. The installer used the same lines from the air conditioner to connect the heat pump to the new air handler. 

The new equipment is from Panasonic

1- CS – HE18YAHK6 Indoor unit 18k BTU’S or 1.5 tons

1- CU – HE18YAHK6 Outdoor unit 18k BTU’s or 1.5 tons with R410A

I have been very pleasantly surprised at how this unit functions, although it is oversized and with the loss of efficiency of the ducting, it does not use as much electricity as I expected or feared. It seems like a good solution for this large old house.

This unit provides heat for one zone of our three zone home, and I am now planning to get quotes for a similar set up for another of the two zones. I have Manual J information to help with sizing in this zone, which we currently heat with a small wood stove and sometimes a large 1800’s Rumford-style fireplace. We probably won’t stop using either once the heat pump is installed, but are looking to reduce the burden somewhat of cutting, splitting, stacking and hauling all the wood we use, and to have a backup system in place. We stopped using the oil burner a couple of years ago and don’t plan to ever use it again.

My question is about the correct thermostat for these heat pumps. The installer put in a generic off the shelf thermostat for the Panasonic heat pump.  Obviously this works, but would a Panasonic thermostat result in greater efficiency because it is better able to communicate with the air handler and the heat pump?  If so, I will specify the manufacturer’s thermostat when I request the quotes.

Any other suggestions? 

We’re in southern Rhode Island, in an average or semi-tight house. 

Many thanks for all the great information on this forum. 

Susan