Our current water heater (gas, tanked) is installed in a little enclosure on our back patio. We want to replace it with a heat pump water heater. We live in Southern CA. It never freezes. Everything I read about them assumes they will be installed indoors. Seems to me that it should be OK if it's outside as long as it is properly vented and protected from the rest of the elements.

A specific example is this Rheem. The installation documents say "Do not install in outdoor, unprotected areas". It also says "It is recommended that the hybrid water heater be installed where ambient temperatures DO NOT exceed 145°F". Which kind of leaves open the option to install outdoors in a protected area (emphasis mine). But nowhere does it explicitly say that outdoors and protected is acceptable.

Our summers are hot but it doesn't get anywhere near 145°F where we would install this. I guess my primary concern is still the temperature (which maybe gets to 110 on a bad day). But going strictly by the documentation it sounds like this would be OK.

  • 2
    Does this answer your question? Is it okay to put a heat pump water heater in a crawl space? Jul 24, 2021 at 5:34
  • I feel like this question has been asked and answered before, i.e. in general, as long as the water heater is properly protected from the elements and the climate is compatible, using outside air isn't a problem at all. See proposed duplicate. If you feel that isn't sufficient an answer, then you should include more details in your question, including but not limited to the exact make & model of water heater, what you've found out already from the water heater documentation, and why you find the proposed duplicate insufficient. Jul 24, 2021 at 5:36
  • 1
    They are installed in Australia outside just fine; make sure drip line goes somewhere sensible - not right next to the house. Jul 24, 2021 at 10:34
  • Does a heat pump water heater produce enough condensate to worry about where in the ground it is drained to? What are the consequences of draining it next to a slab? Jul 24, 2021 at 12:30
  • Are you working with a specific budget limitation? The reason I ask is because I don't see a reason you couldn't use a split-system heat pump water heater in your application (and it might work better than a unitary type unit, even), but they're a fair bit more costly than the unitary units are Jul 24, 2021 at 23:47

1 Answer 1


As far as I can tell, yes, but you'll get dinged on standby losses

As long as the shelter is weather-proof enough to be considered suitable for installing indoor electrical equipment in, you shouldn't run into any major issues with having a heat pump water heater (whether it be a unitary unit, or the tank in a split-system setup) in such an "outdoor" location. The caveat is that your standby losses during "winter" are going to be relatively high, even in a mild climate like Southern California, but you won't have any parasite load issues to worry about, at least.

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge you have read our privacy policy.

Not the answer you're looking for? Browse other questions tagged or ask your own question.