Heat Pump Water Heaters

[laynes69]

A couple of years ago, we had an 80 gallon electric water heater. When the heater went bad, I had to purchase a new water heater. At the time because we had to, I could only purchase a 50 gallon water heater. We have 5 in our family, my wife and I and a 20 and 17 year old boys and a 10 year old girl. Also a year and a half after the purchase of the 50 gallon heater we added a second full bathroom with a large soaking tub.

My wife takes a hot bath every night that just about drains the hot water and my daughter takes a bath almost everyday in the evening. My sons and I take hot showers daily. Our electric bill has been approaching 230.00 a month and wont stop climbing. Our LP furnace is off, we have a gas dryer and a gas stove. My sons have high end computers, there are alot of electronics and we have 2 outdoor security lights (25 a month). In the summertime we run a dehumidifier 24/7 in the basement, however I've airsealed the basement and am working on stopping most of the moisture. Our water heater is currently set at 150 degrees to allow to fill the tub upstairs.

We are looking at getting an 80 gallon heat pump water heater. Not only to produce more hot water, but to dehumidify the basement and eliminate the dehumidifier. What I am wondering is if anyone has any real life data on operating costs and savings? There's currently a 300 tax rebate, 150 dollar Co-OP rebate and through Mendards a 216 dollar rebate.

 

[GENECOP]

I run the Nyle Geyser year round for domestic kitchen faucets, washing machines, etc...for baths and showers, three bathrooms run off an on demand system, no storage, never runs out..

 

[andym]

A HPWH will definitely help on the humidity part. From what I've read, my understanding is that they don't have quite as good of recovery rate (on heat pump only mode). I'm sure you would still be saving money on electric tho. Filling a large tub 2x daily is a lot of Btus.

 

[brenndatomu]

I have been monitoring my electric bill the last 14 months or so since installing our Richmond 50 gallon HPWH...looks like we are averaging $15/mo less...this is with an electric rate of $0.118/kWh (that's taxes, surcharges, everything included) and 4 of us here, 2 adults and 2 kids under 10....doesn't sound like we use as much hot water as you guys though...so far we have only had 2 times where we just started to run out...and IIRC that was after 4 bath/showers in about 3-4 hours (and HPWH set on HP only mode) my wife likes it hot, and she was the last to go...if it had been me I probably wouldn't have had a problem since I only do warm showers.
FYI, Menards only charges $70 for a 10 year warranty extension on those...that's parts and labor IIRC...I don't usually buy extended warranties, but this one seemed like a fair price for what it was.

 

[NoGoodAtScreenNames]

I have a Rheem 50 gallon for 4 people. It comes with an app where you can vary the temp and heating mode on a schedule. I have it heat up to 130F during the day (while power comes from my solar panels) using the heat pump only. This to give a bump for the high demand time. During the evening, when most people shower I run in high demand mode but at 120F and then back to heat pump mode at night at 120F.

Without the solar I would pay about $10 a month.

 

[laynes69]

It feels like we are using more electricity than with our old 80 gallon heater. Our water is ph neutral and we have very good water with a softener. After 2 years I removed one of our elements and they had no buildup and nothing in the base of the tank.

It seems like because the heater is soo small, it's always trying to heat the water therefore having a constant operation of the elements. Having well water, the water is very cold going into the tank.

We are close to 13 cents a kwh with fees and taxes. Our last bill we used 1711 KWH. I have done everything, replaced an old deep well jet pump with a submersible pump, new water heater 2 years ago, new tv, new energy efficient standup freezer. We have a pool that runs 8 hours a day in the summer and have a dehumidifier that also runs in summer. But take out those 2 in the winter and we still are the same.

I cannot understand where our usage is coming from. Our woodfurnace runs 24/7 and that could be some but I know people with an all electric home and their bills are much lower. I'm trying to stop the bleeding and I'm curious if the water heater is the culprit but I've also heard of phantom loads.

 

[brenndatomu]

I'd start investigating... get a clamp on ammeter and start shutting off breakers one by one...see if the load drop makes sense for that circuit...if not, start chasing down the culprit.
The gadget geek in me would love to have one of those power monitor systems, but our bill is not high ($60 spring/fall, $80 winter, $90-100 summer)

 

[laynes69]

I've thought about it. I do know there are breakers that show some heat with the thermal cam, which I can start there.

 

[DBoon]

Just doing some simple math - if you use 100 gallons of hot water daily (not unrealistic based on what you described as your loads) and have 50 degree inlet water heated to 140 degrees, that is a 90 deg differential x 100 gallons x 8 lbs/gallon = 72,000 BTU/day or 21 kWh/day or 630 kWh/month. At $0.13/kWh, that is $2.73/day or $81.90/month.

Roughly speaking, a HPWH would save you about 2/3 of that.

 

[Solarguy3500]

My guess is you're right, and the culprit is the water heater. I have an electric water heater too and I knew it was a big part of my energy usage, but until I installed a consumption monitoring device on my breaker panel last fall, I didn't realize quite how much energy the water heater used.

I got the Energy Curb monitor which gives you CTs (current transformers) for the mains, as well as enough CTs to monitor several individual circuits too. It was pretty eye opening to see the actual usage numbers on the water heater. Curb sends you an email each week with your weekly energy usage report:

I had 3 solar hot water collectors installed on my roof at the beginning of winter, but they haven't been doing much lately since they are covered with snow. It will be very interesting to see the effect on the electric usage as we get into spring and summer and the SHW starts producing more.

I also had a HPWH at my previous house and loved it. It was a State, pretty sure it was 60 gallon and with a family of 5 there were only a few times when everyone in the house took a bath or shower on the same day that it would start to get a little cool when running in HP only mode. But, remember, you can always put it in hybrid mode and then if it needs the elements, they will kick in when the HP can't keep up.

 

[ABMax24]

Are those high end computers turned off at night? Do they spend a lot of time gaming or other intensive loads?

I built my brother a high end PC for christmas for doing CFD in University. AMD Threadripper CPU, liquid cooled, graphics, etc. That thing pulls 150 watts just at idle, and easily pulls 400 watts under load, and spikes over 500 watts. He used to joke that he could shut off the baseboard heaters in his apartment and use the computer for heat when running simulations for days at a time.

I'd be looking hard at those PC's first, new graphics cards can pull up to 320 watts alone, never mind the rest of the PC. Make sure they get shut off when not it use. In summer this issue is compounded, because the AC has that much more heat to pull from the house, using yet more electricity.

 

[laynes69]

They do game alot and I know the power supplies are over 1000 watts. Their video cards alone have 3 fans on aluminum heatsinks. They tell me they put them to sleep and they use no energy but I suspect otherwise.

 

[maple1]

We see a noticeable difference in our power bill in the summer when our 2 boys are home from school and gaming a lot.

 

[maple1]

They do game alot and I know the power supplies are over 1000 watts. Their video cards alone have 3 fans on aluminum heatsinks. They tell me they put them to sleep and they use no energy but I suspect otherwise.

That's like $6/day right there.

 

[laynes69]

I'm going to have to get some sort of monitoring tool. I had 2 breakers that were warmer than the others according to the thermal cam. They very well could be from their rooms. I'll have to do some investigating and try to figure out how to curb some usage. It's not that I cannot afford it but I hate throwing away money.

 

[brenndatomu]

You can get a half decent clamp on ammeter for under $50...unfortunately its almost impossible to find meters made in the USA anymore....I just ordered a Klein multimeter for work that was supposedly USA made...nope, chyna. (Amazon lied to me)
For plug in loads, the Kill-A-Watt works very well!
The last I checked a whole house monitor like SolarGuy mentioned was $2-300...sure are slick though...I suppose it would pay for itself eventually if it helped you to go all "electric bill nazi" easier

 

[EbS-P]

We have an 80 gallon Bradford white HPWH. We are a family of 6. 4 kids under 10. My utility company says I can save 260$ a year. I guessed we could save 20-30$ a month. It’s kind of like heating the water with wood in the winter. We have a finished basement and it makes the basement almost too cold in the winter. I got the overpriced 8” ducting kit. It’s allowed me to intake near the ceiling and put the cold exhaust down on the floor. Better efficiency in the winter and better dehumidifier in the summer. It’s taken the place of one dehumidifier. It’s about like running a 4000-6000 btu ac unit 4-6 hours a day so it does impact heat/cooling demand.
In a perfect setup I would exhaust to upstairs. I would have to run duct through my crawlspace which I haven’t talked yet. If you basement is dusty i recommend a washable pre filter as the one emits units have is just a lint filter. Cleaning the coils on mine does not look simple

Evan

 

[sloeffle]

A number of years ago I was looking at ways to reduce my electric bill. I bought a Efergy and put it on all of the 240V circuits in my panel. When three of us were here it was costing us roughly $50 a month ( .16kWh all in ) to make hot water with standard electric hot water heater. I bought a AO Smith HPHW and dropped that cost down to about $5 - $10 a month depending on the time of the year. I figured my ROI was about 2 years. The only competitor at that time was GE and the reviews on the their HPHW's were horrid.

If I was to buy one today I'd get the Richmond from Menards. It's quieter than the AO Smith, has a higher COP, and you can get connect it to your smartphone. It looks like Menards sells two different 80 gallon models. They sell the 10E80-HP530 ( 2k ) and the 10E80-HP515 ( 1.6k ). The more expense unit has a (broken link removed) than the other unit. The more expensive unit also has a better first hour rating, and a higher recovery rate which might be important for a situation like yours. According to their numbers you'd save $44 a year with the more expensive unit. If the unit lasts more than 9 years, you've got your money back. But with your usage, I'd bet your ROI will be less than 9 years.

EDIT: After looking some more, Menards sells a version of the 10E80-HP530 without leakguard for 1.6k. It looks like the 2k unit has leakguard protection on it.

 

[laynes69]

Our water heater is about 3 feet away from our woodfurnace. In the winter it would be great because of the extra heat from the flue and furnace. With that said it sounds like we would save a ton in the winter. Of course we use the most hot water in the Winter. The model 10E80-HP530 is the one I am looking at as long as it will fit in the basement.

 

[brenndatomu]

According to their numbers you'd save $44 a year with the more expensive unit. If the unit lasts more than 9 years, you've got your money back. But with your usage, I'd bet your ROI will be less than 9 years.

$44 per year? Its gotta be higher than that...

 

[Brian26]

Keep in mind the yellow energy guide sticker on HPWH's is for the unit running in hybrid mode and still using the elements. I think I read they all default to that mode when first turned on so the sticker is based on that. When I monitored mine for a year it was costing like a fraction of what the sticker said when running in heat pump only mode. I think it was using about $7-10 a month in electricity.

Also, my 2nd generation Geospring just hit 8 years running nonstop in heat pump only mode with no issues. It has been rock solid reliable.

 

[brenndatomu]

FYI, Menards puts those units on sale with rebate also once or twice a year...usually in the summer...might save you another $150-200.
Example: The 50 gall unit that I have is $1156 now...I got mine with sale and rebate for $950(ish) plus the $70 I paid for the extra 10 yr. warranty.

 

[sloeffle]

$44 per year? Its gotta be higher than that...

Between the two 80 gallon models that Richmond offers. One has a COP of 3.7 and other unit has a COP of 4.0.

(broken link removed)

 

[sloeffle]

Also, my 2nd generation Geospring just hit 8 years running nonstop in heat pump only mode with no issues. It has been rock solid reliable.

Was it the 1st generation Geospring's that had all kinds of issues ? I'm on my second AO Smith HPHW, the compressor died on the first one and AO Smith gave me a new one for free under warranty.

 

[begreen]

I'd like to put one in, but our pit basement has no drain. It makes me nervous to rely on a condensate pump down there, year after year.