If the water heater is in conditioned/semi-conditioned space the overall efficiency of a heat pump water heater is pretty much wasted in a heating-dominated climate such as Portland (whether it's Portland ME in US climate zone 6 or in OR climate zone 4.) Putting it in an unconditioned garage or something,even if it's still capable of making hot water at +20F the coefficient of performance (COP) / EF takes a serious dive at those low temps.
The in-situ EF at the average annualized temp of the space where it's located gives you it's electric-heating efficiency, but does not factor in the increased space heating load on the heating system created by pulling heat from conditioned/semi-conditioned space, nor the fuel source & AFUE of the heating system that supports that load. If it's sucking heat out of conditioned space in a house heated with a low efficiency fossil-fired steam heating system you'd be way kinder to the planet and yourself doing something else for hot water. But if it's' in conditioned/semi-conditioned house is heated with a high-efficiency ductless heat pump or ground source heat pump it's likely to be a financial net-win, but whether it's better for the planet than condensing gas-fired system depends on the actual local power-grid sources.
These water heaters are much better suited to cooling dominated or mixed climates like US climate zones 1-3 where there it's more likely to net-win than US climate zones 4-7.