[cmurphycode]

That's definitely part of it. I'm actually surprised it's working in heat pump mode at all. We have a hybrid and it will run pure-resistive if the ambient temperature is below 50. Now, it's in our basement, so even in the winter that's a reasonable cut-off - not sure if you got a specific model for being "outside".

Speaking of which, does your model not have a resistive backup? Ours has several modes:

- only use heat pump, unless not safe to do so (ambient too cold) - use heat pump normally but fall back to resistive to recover - use resistive only

We only have 2 people in the house so we are able to leave it on the first mode, but in the second mode it would, presumably, be the same performance as our old resistive-only heater.

[isbjorn16]

Solid questions - I'm going to take a peek at it tonight. I honestly haven't given it a lot of thought, but literally just this morning my wife went off on a rant about it for a good 15 minutes. It suddenly bubbled up my priority queue pretty quick - and then out of nowhere, this thread on heat pumps and water heaters! Crazy coincidences sometimes.