Well it has been just about 5 days since i installed the Demand Defrost Board in my Goodman heat pump.
I also installed two electronic counters so that i could determine how long and how many times the heat pump has gone into defrost.
One is a cumulative timer / hour meter that keeps track of the time the aux heat is energized during defrost the other is an event timer and it just counts the number of times the aux heat is energized during the defrost mode.
Note in my setup, when the heat pump goes into defrost is energizes a 10kw heat strip, when the t-stat calls for aux heat because the temp is below the balance point temp it only energizes a 5kw heat strip.
The white rodgers board will automatically do a short defrost cycle every 6 hours of compressor run time and so far it has logged 8 events each lasting only about 30 seconds.
So far I have not seen any frosting on the coils and while it has been dry here the temperatures have been quite cold.
yesterday the low was 18 and the high was 25 this morning it was 10.5 degrees and it is not only 20 degrees out at 11 am.
I go out and check the coil for frosting at least 4 times a day but so far no icing or frosting to the coil is present and no defrost events have happened.
The cumulative timer has only logged about 3 minutes of aux heat from calls from the heat pump for aux heat during defrost which only represents the 8 events which the board automatically does at 6 hours of compressor run time.
The demand defrost board has cut the daily energy usage from aprox 120kwh a day in 26 degree weather to less than 80kwh a day even in these cold temps.
The addition of the demand defrost is a huge energy savings at least as of now. I suspect when it gets a little warmer and a little wetter it will ice up and actually need to go into defrost but as of now i have avoided the dreaded 90 minute unnecessary defrost cycles.
With the old defrost board it would have defrosted 35 times unnecessary, based on the 53 hours of heat pump run time in the last 5 days, resulting in much less wear and tear on the compressor / reversing valve / heat strips and lastly savings huge amounts of electricity.
This simple change will pay for itself in about 1 month of usage.