Old heat pump technology required supplemental heat on colder days. In my area this was typically strip heat that on colder days could be costly. The latest heat pump technology uses two compressors and requires no suppliemental heat even in the coldest (lower 48 US) days. In fact one of the manufactures of the new dual compressor Heat pumps is in New Hampshire. The latest Heat Pump is worth looking into. iF YOU LIVE IN THE NORTH i DO NOT ADVISE THE OLDER HEAT PUMP THAT REQUIRES SUPPLEMENTAL HEAT.