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Heat pump water heater in small closet vent to finished basement

user-7591582 | Posted in General Questions on

Hi!  I’m trying to convert my natural gas water tank heater to a heat pump water tank heater.  I want to use more renewable energy sources like our solar panels.   I’m looking at the Rheem HPWH 80 gallon.  The room it would be installed in is a small 40 sq ft HVAC closet and also has our furnace.  My options are to install louvered doors, or to vent it with insulated duct.  The room is an interior room so vented to the outside of the building would be really expensive.  I’m thinking about getting a louvered door and then having the exhaust vent go through the closet to the finished basement area that is 800 sq ft adjacent to the closet.  Am I crazy?  Will this work?  I think the louvered door alone is not enough even though the manufacturers specs says it is fine.  Don’t want to have the closet temp drop so much.  We live in Colorado and the temp of the basement year round is 65-70 degrees.  I just feel crummy about using fossil fuels again.  The Sanden HPWH looked a little expensive for our budget.  Is this a good plan?  Other options I should consider.

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  1. john_heckendorn | | #1

    If your existing water heater is vented to the outside, why not re-use that route for the exhaust from your Rheem? Or find a way to connect the exhaust vent to your adjacent furnace's exhaust vent (if that can be done to code)? And for efficiency's sake, would be nice if you could somehow use some of your furnace's waste heat with your HPWH's intake, rather than draw all the heat from your living area.

  2. user-7591582 | | #2

    Thanks for the reply! The existing vents are not insulated and are only 4 inch. So I don’t think that would work because the requirement calls for an insulated vent. Yeah, we’d have the intake come Directly from the furnace / Water heater closet, and push the exhaust to adjacent finished basement.

  3. brad_rh | | #3

    I think your idea is good. I'm doing something similar with mine which is in a shop, and blows into the garage. The only problem might be cooling off the basement

    1. john_heckendorn | | #4

      Maybe, but look at the recent GBA article on HPWHs (or rather the comments, which includes a quick and dirty discussion on gauging the effect of heat pump exhaust on a basement). Depending on the total volume of the basement, the effect could be pretty negligible (and actually beneficial during the summer).

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