Have you seen this heater attachment?

I ran across this ancillary heater at an inspection a couple days ago. I’m wondering if others have had experience with this at all. If so plez share any specifics.

NOTE: It is obviously non functional but it looks like quite a heating system in its day.

Used to heat domestic water from waste heat of the AC unit.


Just from what I can read off the name plate it uses a fractional HP blower motor so it basically is a small unit. Appears to have two coils one for heat probally served by a HW tank and one with an A-coil using cap tubes for its expansion valve because it is set up for R-22 R-500 R502 there is no such thing as dual refrigerant expansion valves. (TXV)

The system would still be considered a split system because of the refrigerant lines.

IMHO the unit used is a poor choice for a exterior wall mounted unit

It uses the heat transferred from the interior air to the refrigerant coil to heat the domestic water. Before the line goes back to the compressor it goes through the ECU.

It’s a Heat Recovery Unit, extremely common in Florida. Uses waste heat from the condensing unit to assist the water heater. Almost always mounted on the exterior wall adjacent to the condensing unit. Local utility companies used to offer a monthly rebate to customers that chose to install them.

Almost all of them have been disconnected by HVAC technicians or plumbers (when installing a new water heater). Less than 25% of the ones I see are still active.


Thanks everyone. That heat recovery unit pdf file is going into my library.