April 10th marks the 1 year anniversary of installing a Rheem 50 gallon 'Hybrid' water heater in the house. I've posted on it before, but to recap.
I have, what I feel, is a 'best case' scenario for one of these. My water heater is in the garage, I live in Georgia, and my garage faces the afternoon sun.
I have a single day, in the past, where I was the only one home, the HVAC was off, and other than LED lighting, the only thing I did that day was taking a shower and heat water with a standard resistive water heater. The result of that, was approximately 4KWh used for that day, so keep that number in mind with the HP data.
The WH is locked into heat pump mode and does not run the elements....EXCEPT. On December 23rd of 2022, GA had some of the coldest temps I remember in years (11* low, 7* the next day) and , and the garage went from its usual above freezing temps, to well below, I think it may have been in single digits for a while. It was cold enough to freeze my condensate line from the water heater, so it was cold. Rheem has the unit programmed to run the elements in that case(the compressor did not run at all, I suspect either because it would be of no use or to protect it from damage), and it is very apparent that they ran, racking up 9KWh for that day.
Some points:
Average usage over 370 days: 3.676685 KWh/day
Highest day: 9.95 KWh
Set temp 136* (57.77c)
People in the house: 3 (all adult)
The dishwasher in use and clothes get washed warm/hot.
Most days there are a minimum of 2 showers and usually, a load of laundry or dishes is done in the house. Sometimes more, but usually never less.
The economics of the unit are.
$1100 Paid for the unit. Figure another $150 in install stuff (PEX, Fittings, Crimpers, Pump, Etc)
Local EMC Rebate - $500
US Gov Rebate - $300
A very rough estimate is that I've saved around $300 so far in a year in power, so that leaves me with just around an 18-month payback on the unit. I'll admit, I bought it for the right price, and the rebates knocked a big chunk out of it, as well as being able to install it myself helped.
Odd note. If you have one of these, and you go on vacation, kill the power to the unit. For some reason, it will use 1KWh a day just being in 'vacation' mode, which you would think is off. You can see that in my graph where we took a vacation in May of 22 and then again in March this year where I just threw the breaker and left.
I did run with the 'energy saver' mode turned on, and from what I see, it never ran the elements for me, but it did some screwy things with the schedule of when it ran and didn't suit our usage since we both keep odd work hours. I noticed that I sometimes didn't have good hot water when I wanted it, so I switched it back to straight-up heat pump mode.
We never really run out of hot water, although with a back-to-back run of showers, you can feel it get low, and of course, it does take longer to recharge, but never to the point of wanting to turn the elements on to make up for it. We've always had enough hot water when we need it and haven't really changed our usage pattern. Although, I will tend to wash my clothes earlier in the day rather than in the middle of the night like I used to on my days off to take advantage of warmer garage air temps.
All-in-all, still extremely pleased with the purchase.
The orange line is a 7-day rolling average, you can clearly see the Dec 23rd event.
You can clearly see how the COP goes down as outdoor temp drops. (Both Aprils are incomplete months)
I have, what I feel, is a 'best case' scenario for one of these. My water heater is in the garage, I live in Georgia, and my garage faces the afternoon sun.
I have a single day, in the past, where I was the only one home, the HVAC was off, and other than LED lighting, the only thing I did that day was taking a shower and heat water with a standard resistive water heater. The result of that, was approximately 4KWh used for that day, so keep that number in mind with the HP data.
The WH is locked into heat pump mode and does not run the elements....EXCEPT. On December 23rd of 2022, GA had some of the coldest temps I remember in years (11* low, 7* the next day) and , and the garage went from its usual above freezing temps, to well below, I think it may have been in single digits for a while. It was cold enough to freeze my condensate line from the water heater, so it was cold. Rheem has the unit programmed to run the elements in that case(the compressor did not run at all, I suspect either because it would be of no use or to protect it from damage), and it is very apparent that they ran, racking up 9KWh for that day.
Some points:
Average usage over 370 days: 3.676685 KWh/day
Highest day: 9.95 KWh
Set temp 136* (57.77c)
People in the house: 3 (all adult)
The dishwasher in use and clothes get washed warm/hot.
Most days there are a minimum of 2 showers and usually, a load of laundry or dishes is done in the house. Sometimes more, but usually never less.
The economics of the unit are.
$1100 Paid for the unit. Figure another $150 in install stuff (PEX, Fittings, Crimpers, Pump, Etc)
Local EMC Rebate - $500
US Gov Rebate - $300
A very rough estimate is that I've saved around $300 so far in a year in power, so that leaves me with just around an 18-month payback on the unit. I'll admit, I bought it for the right price, and the rebates knocked a big chunk out of it, as well as being able to install it myself helped.
Odd note. If you have one of these, and you go on vacation, kill the power to the unit. For some reason, it will use 1KWh a day just being in 'vacation' mode, which you would think is off. You can see that in my graph where we took a vacation in May of 22 and then again in March this year where I just threw the breaker and left.
I did run with the 'energy saver' mode turned on, and from what I see, it never ran the elements for me, but it did some screwy things with the schedule of when it ran and didn't suit our usage since we both keep odd work hours. I noticed that I sometimes didn't have good hot water when I wanted it, so I switched it back to straight-up heat pump mode.
We never really run out of hot water, although with a back-to-back run of showers, you can feel it get low, and of course, it does take longer to recharge, but never to the point of wanting to turn the elements on to make up for it. We've always had enough hot water when we need it and haven't really changed our usage pattern. Although, I will tend to wash my clothes earlier in the day rather than in the middle of the night like I used to on my days off to take advantage of warmer garage air temps.
All-in-all, still extremely pleased with the purchase.
The orange line is a 7-day rolling average, you can clearly see the Dec 23rd event.
You can clearly see how the COP goes down as outdoor temp drops. (Both Aprils are incomplete months)
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