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Community and Q&A

Heat Recovery Water Heater System

greenleopard | Posted in Energy Efficiency and Durability on

I can’t find any articles about heat recovery units which use your A/C system to heat your water. It seems like a great idea, it’s amazing the only unit I found is so expensive though, it’s seemingly a simply device. Does anyone know of any calculations for payback time, savings? It would work with electric, gas, or heatpump water heaters.

There is one on Home Depot for $700 called
Heat Recovery Water Heater System – Zero Energy

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  1. Expert Member
    Dana Dorsett | | #1

    A lot depends on the duty cycle of your air conditioner and the cost of your electricity, and how much hot water you use, and what the energy sources/costs for your hot water heater is.

    Payback for me would be "absolutely never", since I have very low sensible cooling load- most of my air conditioning comes from running a dehumidifier in the basement. The ridiculously oversized central air rarely runs more than 25 hours in a given year roughly a ~0.3% duty cycle.

    With a right-sized air conditioner in south Florida I would expect a duty cycle 50-100x mine, and very different economics.

    The manufacturer isn't very free about sharing hard data on the performance, seems more interested in testimonials for their marketing, which is never a good sign. That's well short of a third party bench test with real BTU numbers.

  2. greenleopard | | #2

    Thanks for the link. I recognized the newscaster, that's my local news, turns out the company is HQ about 2 miles North of one of my houses haha, I think I'll pay them a visit one day!

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