GBA Logo horizontal Facebook LinkedIn Email Pinterest Twitter X Instagram YouTube Icon Navigation Search Icon Main Search Icon Video Play Icon Plus Icon Minus Icon Picture icon Hamburger Icon Close Icon Sorted

Community and Q&A

Has anyone used the Rheem hybrid water heater?

Danny Kelly | Posted in Green Products and Materials on

Seems like a great product – Energy Factor of a 2.0 as long as it has 1000 cubic feet of air space around it. I am in NC so according to their chart, we are in zone 1 which would use the heat pump option 90% of the time. It says to install it in a “warm site like an attic, garage or basement” – half the year, those areas are not very warm so was thinking it may just work better inside the thermal envelope – besides, I need to stay within 40 feet of all plumbing fixtures in order to get my points on the National Green Building Standard so locked into putting my water heater in the utility closet located in the center of the home. My concern if I put it inside the thermal envelope is – am I creating an energy penalty during the winter when it is creating cool air and how much cool air does it create – will it be noticable to the occupants? The utility closet is not quite 1000 cubic feet so was planning on installing a transfer grill into the laundry room to get the required cubic feet of air so will not really be in the immediate living area if that helps.

GBA Prime

Join the leading community of building science experts

Become a GBA Prime member and get instant access to the latest developments in green building, research, and reports from the field.


  1. GBA Editor
    Martin Holladay | | #1

    Yes, heat-pump water heaters cool the space in which they are located, and therefore make your heating system work harder in the winter.

    I would be leery of installing the water heater in a room that is smaller than the minimum space recommended by the manufacturer. Before proceeding, you should talk to a technical rep at Rheem.

  2. user-626934 | | #2


    I didn't see the exact capacity information in the Rheem website, but it's probably in the range of 5,000-10,000 Btu/hr while in heat pump mode. Yes, it will cool the space. Yes, it will be noticeably cooler in the utility room, especially near the end of the cycle.

    While the extra space heat load in winter is a "con", the HPWH will also take a little cooling load off your AC during the summer. The net difference over the course of the year in NC (extra load in winter - reduced load in summer) is probably negligible, but it does depend on a few factors (such as incoming water temperature, DHW demand differences in summer vs. winter, heating/cooling system efficiency).

    One other benefit is a small amount of year-round dehumidification, which is rarely unwelcome in a tight-house in a mixed-humid climate.

    Also, pay attention to the location of the utility room...all the HPWHs are a little loud...think 1980's-era refrigerator.

  3. Danny Kelly | | #3

    Martin - I did speak with a Rheem rep - the 1000 cubic feet is for optimum performance and it is necessary to achieve the 2.0 EF - if installed in a smaller room, the EF may be reduced to 1.5, so it is recommended and not required. I do need to follow up with them if my transfer grill into the laundry area will work though.

    JOhn - good points, thanks for the thoughts. Was not aware it would dehumidify, I was actually worried it may increase RH since it would be reducing the temperature without removing the moisture - nice bonus.

    Thanks for both replies.

  4. user-869687 | | #4

    Someone should make a combination water heater / refrigerator using the same heat pump. It's silly to have one appliance generating waste heat and another appliance generating waste coolth. The two could operate at opposite sides of the same wall, or with a run of copper tubing like a mini split.

Log in or create an account to post an answer.


Recent Questions and Replies

  • |
  • |
  • |
  • |