HEAT PUMPS IN ALASKA
With regard to the performance of the MItsubishi ASHP in DIllingham: We believe the issue was likely due to the controls for that specific heat pump. We attempted several times to discuss this problem with Mitsubishi but they were nonresponsive to our inquiries. A 2015 report by Williamson & Aldrich found integrated daily COP values of less than 1 for related Mitsubishi models (FE12 and FE18), but the report doesn't indicate whether it was also found for steady-state samples or whether the COP values below 1 were purely due to teh defrost penalty. Additionally, we never measured COP values at warmer temperatures because the house in whcih this was isntalled was considered to be super insulated and thus the heat pump was never run at outdoor air temperatures warmer than about 35 degrees.