We have a Mitsubishi Ecodan pump to do hot water and underfloor heating. Generally we are very happy with it but we're slightly surprised about how quickly the water tank loses heat. Here is a graph - the "room temperature" is actually the temperature of the cupboard that all the kit is all crammed into (it's very small and a tight fight). The house is brand new so is generally very well insulated - should I expect the pump to have to come on every 12 hours or so? Is this normal? Here we didn't use any hot water at all from 8pm to 7am.