Tying two different heat sources into one system is not uncommon. One has to take into account the operating parameters of each heat source, as well as the configuration and make-up of the rest of the heating system, such as the heat emitters (e.g. ducts, baseboard, panel radiators, radiant floors, etc.) and the controls.
Pellet boilers generally operate at temperatures above 140 °F (usually 155-185°F). Heat pumps on the other hand cannot operate that high, and in any case operate more efficiently the lower the output temperature. Output temperatures of 110-120°F are more typical with any kind of heat pump.
Combining pellet boilers and heat pumps can work of the strengths of each, but the system control has to be set up so they don’t get in each other’s way. The heat emitters must also be able to function suitably well at the lower temperatures produced by the heat pump. Conversely, low temp heat emitters are not a problem for the pellet boiler as hot boiler water can be mixed in with cooler “return” water in order to achieve appropriate temperatures.
Contact EcoHeat Solutions for more details.