> Well that installer cutoff was likely waaaaay too high. Your heat pump should be fine to 30F, maybe even 25F before needing gas One possibility might be that

> Well that installer cutoff was likely waaaaay too high. Your heat pump should be fine to 30F, maybe even 25F before needing gas One possibility might be that the unit lacks de-icing circuitry. If that were cut for cost optimization, the unit would still work fine for cooling and for moderate-temperature heating, but anywhere near 30F it would ice up and stop working.