I have a Trane xl15i heat pump, an XV80 natural gas furnace and a Trane TCONT803 stat with dehumidify feature. I have my heat pump lockout set at 25.
My natural gas service is currently turned off. I monitor the forecast and when I see it is going to get bitter cold I will call and have it turned on. I didn't have it turned on until mid January last year and then didn't need it that much. I save a little by only having my natural gas turned on 2-3 months a year and my local utility does not charge a connection fee if it has been off for 8+ months.
I've noticed a few times recently where the heat pump fan stops and the heat pump makes a buzzing noise. I assume this is a normal defrost cycle. When this was happening I measured the temperature coming out of my registers at 40 degrees (I have black and decker thermal leak detector). This was happening for several minutes. The heat was set at 70 but had dropped to 66 when this happened over just a few minutes. This was with outside temperature of 27 shown on the stat and normal heat mode (not aux heat). Is this the expected behavior? Should my furnace fan turn off during the defrost cycle to prevent my house from being cooled?
thanks for any help with this...