My (NIBE) heat pump uses this approach and it works well for keeping the temperature constant as the weather changes, but it doesn't seem well-suited for situations where the house must be brought up to temperature from cold. Say after a power outage, or after a temperature setback period. It seems that the heat pump adds enough heat to offset the losses to the outside, but doesn't add any/enough to raise the temperature.
Not a problem for us as we keep the temperature steady, but if you wanted to vary the temperature significantly this may need some override based on the internal temperature.
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