This controller is what I see normally. One day the idiot light was blinking and it says [replace filter]. I went up inside the roof cavity above the ceiling, to check the filters. On top of the pink batts insulations are numerous large conduits from the HRV units.
I was using oil storage heaters for my winter heating for 16 years until recently. Three oil heaters came with the house; but a dehumidifier was required to run full time to stop the windows tearing up in winter. Those oil heaters are good but low tech and did not allow instant heat control because I was using off-peak current which was controlled by a time clock. The power supply is turned on automatically at midnight for 4 hours heating the oil inside the heaters. During the rest of the day heat is radiated slowly to keep the house warm.
|second heat pump|