Adding a Heat Pump Water Heater in series with an Oil-fired Coil
I’m looking into installing a Heat Pump Water Heater (HPWH) in series with an oil-fired boiler with a domestic hot water heating coil.
My present thinking is to use the oil-fired boiler coil to pre-heat the water and have the HPWH finish the job, particularly in the winter months. I’m also thinking that I would plumb in a by-pass capability so the HPWH would do the entire job of heating the water in the warmer months.
Does this make sense or should I just disable the coil in the boiler? Does anyone have any experience with doing this, or have any suggestions?