Heat Pump Water Heaters Vs Gas and Electric

[pawanranta]

How efficient are heat pump powered water heaters when compared with gas-fired and electric resistance water heaters. I have read some wild claims on the internet. This Mulgrave based installer offered to replace my existing gas water heater and installer heater pump based water heating unit having energy efficiency:

6 – 7 times more efficient than gas fired water heaters and 3 – 3.5 times more efficient the conventional electric water heaters.

 

[chrisski]

I measure efficiency in cost to me. After installed, gas is significantly cheaper than electric in my area. Your quote shows the exact opposite.

For a new central AC for a house, I really think you need to buy it and have it installed to find how much it will cost you in a year. Can’t seem to get a straight answer

 

[shazam]

Actual usage for 2 people....80 gallon electric last year, 80 gallon heat pump this year....

July 1 to July 8 @ 9am.....10.1 kWh. Same period last year......20.0 kWh. YMMV

The IotaWatt is my friend!

Jim

 

[jpwhit]

Here is real world data from my install. I installed one in my lake house 11 months ago. Here's the Emporia Energy Monitor reports showing before and after. Exact same usage conditions for both graphs. Around 60 kwh per month for electric, around 20 kwh per month for hybrid.

I didn't do it so much for the energy savings, even though it's a good payback period, I did it more for saving money on hybrid inverter costs. I also installed heatpump based dryer, and lots of variable speed minisplits for the same reason. I run my whole 4000 sq ft lake house off of a 9.6k inverter. Without these changes, I would have needed double that at the cost of an additional $3.5k. Hybrid hot water heater only pulls about 600 watts from the inverter but runs over a longer period of time.

I got the heat pump water heater from Home Depot on sale for $900. After the tax break it cost me $600.

Electric Hot Water Heater



Hybrid Hot Water Heater

 

[chrisski]

I didn't do it so much for the energy savings, even though it's a good payback period, I did it more for saving money on hybrid inverter costs.

That is similar to me wanting to install the inverter AC. My payback period for the inverter AC appears to be 30 years, but now with the huge surge gone, the hybrid inverter will run it.

 

[OffGridInTheCity]

I bought a 50gal Rheeme hybrid (heat-pump capable) hot water heater in 2019. I run it in heat-pump only mode all the time.

Efficiency isn't the big point (for me) so much being 100% electric, reasonable $, no-extra-maintenance, and low wattage (400w max heat-pump mode vs 4500w for heating elements) so I can run via my off-grid solar system without strain.

From a cost perspective it's the difference between electricity (for heat-pump) vs natural gas in my case.

Natural gas ~$1/therm was running me ~$30/month on a 2008'ish 50gal model. At 15c/kwh I'm currently paying ~$20/month with 50gal Rheeme heat-pump mode.
So I save ~$120/year in dollars compared to the old natural gas fired unit.

Of course natural gas and electricity prices can change at any time and the price of the units has dramatically changed over time as well. Mine only cost $300 after rebates so I've come out ahead - but current prices are thru the roof so.....

 

[Zwy]

How efficient are heat pump powered water heaters when compared with gas-fired and electric resistance water heaters. I have read some wild claims on the internet. This Mulgrave based installer offered to replace my existing gas water heater and installer heater pump based water heating unit having energy efficiency:

I'd replace the water heater myself.

27 Kwh per gallon of propane.

Average propane water heater use in a household- 200 to 300 gallons, I use 300 gallons for calculations and based upon my experience this is about correct running washing machine and I have hot water plumbed to dishwasher.

27 x 300 = 8100 Kwh per year/ 675 Kwh per month

At 200 gallons, 27 x 200 = 5400 Kwh per year/ 450 Kwh per month

We have been using average 95 Kwh per month using heat pump water heater on heat pump only mode. all power supplied by solar system

With propane at $1.45/gallon, it would be $435/year at 300 gallons and $290/year at 200 gallons.

Heat pump water heater is $0.00/ year so far. Cost was $1500 and is reduced by federal tax credit to $1050. Payback will be 2.5 to 3.5 years.

I still have the propane in series with the heat pump water heater, this doubles the storage and provides hot water is there an extended cloudy period in winter. I figure the anode rod will last twice as long in the propane unit now.

 

[k490]

My utility was offering a pilot program install a free heat pump water heater. The only time I see a big savings over old one is during the summer our garage gets over 100F I take advantage of that heat run it on heat pump only. Also installed a mixing valve set the heater to 140F the mixing valve is set to 120F. Not sure if that saved anything much. If I had to buy one was offered electric or heat pump probably go heat pump. If I as offered Gas I would always go gas. Gas heating is the best IMO.

 

[Warpspeed]

How efficient are heat pump powered water heaters when compared with gas-fired and electric resistance water heaters. I have read some wild claims on the internet. This Mulgrave based installer offered to replace my existing gas water heater and installer heater pump based water heating unit having energy efficiency:

Heat pump performance is improving all the time, but typically the heat output from a heat pump will be multiples of the direct electrical power the heat pump uses. A lot also depend on outside temperature. If its sub freezing outside, its going to be a lot less efficient than if its hot outside, so no direct figures are possible to compare heat pump performance to direct electrical heating.
But typically you will gain a very great deal.

The problem is the initial cost of the heat pump. It will be cheaper to run, but it might take a very long time to recover the high initial cost in electricity savings.

Natural gas or propane is highly variable in cost depending on your location as well.
Electricity tariffs are all over the place too, so there is no way to answer your question directly with hard figures, as you could be located anywhere in the world.

 

[Rmart30]

We have had our Rheem heat pump water heater for about 5 months now. iirc she said its using 100-120 kwh a month.

The unit was $1700 and we had a local rebate of $650. then have the $2000 fed tax credit.

Im going to use the old water heater tank and run a panel straight to the lower element and do a pre heater tank. Im betting it will drop that 100-120 kw usage in half.

 

[Rmart30]

This guy has a great video on breakdown of cost/efficiency.

 

[Recovering EE]

Call me when there's a tankless heat pump water heater.

I write that partly in jest, as right now, I don't see *any* heat pump being able to output the instantaneous BTUs necessary for a tankless.

 

[time2roll]

Call me when there's a tankless heat pump water heater.

I write that partly in jest, as right now, I don't see *any* heat pump being able to output the instantaneous BTUs necessary for a tankless.

Do you have a tankless now? Gas or electric? Do you like it?

 

[upnorthandpersonal]

Call me when there's a tankless heat pump water heater.

Electron - iE1

Intellihot iE1 is the best tankless heat pump water heater for your commercial needs. Find out how a tankless heat pump water heater can benefit you.

www.intellihot.com

 

[Hedges]

My natural gas water heater + range cost me $8/month.
Nothing I could replace that with would save money.

Natural gas here is 1/8th the price of electricity per unit energy, so about 1/8th the cost of operating resistance water heater (haven't figured out difference in heat loss. Mine has straight flue while some have a thermostatic baffle.)

If heat pump efficiency 400%, then operating that would only cost 2x what gas does.

If I roll my own kWh with DIY PV for 1/20th of retail cost, that changes the tradeoff. Loss of net metering will mean only heat when the sun is shining. If I have surplus I can't store or otherwise use, better for me to run resistance water heater than give to PG&E for $0.02 to $0.04/kWh or pay (higher?) price for HPWH.

That said I might buy HPWH for one property while the rebate and credit gittin is good. Plumb it in series with gas, make hydronic loops and heat exchanger in central heat air handler. Two ways to heat everything, and that property will be NEM 2.0 for 20 years. I might duct the air for that HPWH outside.

Living offgrid and maybe with propane the considerations are different.

 

[Recovering EE]

Do you have a tankless now? Gas or electric? Do you like it?

Natgas. LOVE it. It's a pricey one, sometimes used commercially, or for heating. Navien. Over two grand, plus installation.

 

[Warpspeed]

Natural gas here is 1/8th the price of electricity per unit energy, so about 1/8th the cost of operating resistance water heater.

Pretty much the same economics weigh in here too.
Natural gas water storage heater, hooked up to a large capacity solar preheater are definitely the optimum solution where I am.
But in other countries/states/climates, the situation can be very different

 

[Zwy]

Call me when there's a tankless heat pump water heater.

I write that partly in jest, as right now, I don't see *any* heat pump being able to output the instantaneous BTUs necessary for a tankless.

If you want on demand, go gas. I have one in the shop, always have to wait for hot water but it works great with the pressure washer.

 

[OffGridForGood]

I ran the numbers for a Heat Pump HWT and it didn't work - the initial cost of the HPHWT was just too high for the benefit.
but paying a bit more I got a whole home ducted mini split and this has blown my mind how well it works and how little energy it is consuming.
Some time in the future a heat pump HWT may be in the cards, but not this year.
Do the math, compare, look at options and in the end do what works for your situation I say.

 

[OzSolar]

Specs state 3,500 CFM air requirement. You'd cycle all the air in 2,000 ft2 house over 5 times per hour.

https://www.intellihot.com/wp-content/uploads/2023/01/iE1-Product-Spec-Sheet-1.24.pdf

 

[Citlalatonac]

Heat pumps are nice.

-Most expensive
-Slower, no instant options
-Needs condensate drain

-No exhaust venting
-High efficiency
-Cools and dehumidifies
-Most qualify for 25C 30% tax credit

New build 100% go heat pump. Retrofitting might mean you lose some of the benefits, or have additional costs.

Important to note, the IRA has a rebate program that's just barely started rolling out. Some will be able to get 100% rebate on heat pumps, i would guess most here would get 50% rebate(not tax credit), or have too much income to qualify. Only New York is currently avaliable.No idea when your state or mine will get on board, tribes are administering a separate pot of money.

Other rebates may be avalibe.avaliable.

https://www.energy.gov/save/rebates

Household electrification incentives calculator from Rewiring America

Find out how much you could save with tax credits and rebates for heat pumps, water heaters, electric vehicles, electric stoves, rooftop solar, wiring upgrades, and energy efficiency improvements to your home.

homes.rewiringamerica.org

Product Finder — ENERGY STAR Certified Heat Pump Water Heaters

Compare ENERGY STAR Certified Heat Pump Water Heaters, find rebates, and learn more.

www.energystar.gov

 

[Warpspeed]

Heat pumps are nice.


-Cools and dehumidifies

Nice if your hot water heat pump is located indoors and you live in a hot humid climate.

If its indoors and you live in a cold climate, the extra cooling may not be welcome.
Many things to consider.

 

[Citlalatonac]

Nice if your hot water heat pump is located indoors and you live in a hot humid climate.

If its indoors and you live in a cold climate, the extra cooling may not be welcome.
Many things to consider.

Yeah, and my point about retrofitting was that most hot water heaters hookups in the south are outside the envelope, negating that benefit.

Even up north, the dehumudification can be okay in a basement.

In pretty much every case, except if I've got a nice PV array that puts out more zap than I use or I can get heat pump for significantlyless, I'd go tankless gas.

Stuff like this is generally hard because it really depends on not just local factors, but unique individual factors.

 

[Rider]

I've been running an AO Smith 50 gallon heat pump water heater for a few years, and only run it in heat pump mode. It was never about the cost to operate, although my electric bill did go down a bit after it was installed. More so, it was the amount of power required to operate it. Yes, it does take much longer to recover to 120*, but I live alone and that is just not an issue.

We had a hurricane come thru about 10 years ago, and power was out for a full week. At that time I had a 2200 watt generator which gave me basic necessities, but the lack of hot water and a shower was a problem. When it was time to replace the hot water heater, I opted for the hybrid. In heat pump only mode, it draws a mere 600 watts and can be powered by nearly any 240V source. My newer 240V generator hardly notices it turn on.

In the middle of adding a whole-house battery backup. The hybrid hot water heater can be easily powered by the battery system.

So again, for me it was self-reliance, not cost, that led me to a hybrid.

 

[Zwy]

Nice if your hot water heat pump is located indoors and you live in a hot humid climate.

If its indoors and you live in a cold climate, the extra cooling may not be welcome.
Many things to consider.

Get both weather types in IA, right now the air is so heavy, this is humid crap. We used to run a dehumidifier in summer in the basement, no need with the HPWH. Helps with keeping the house cool too.

As for winter, it gets cold. However, I've been heating my house for all but 2 months in winter using the heat pumps and not the propane furnace, this is all powered by the solar system. With my hybrid heat pump water heater, I can also use just the element and use it as a dump load and rely on the propane water heater to finish heating the water.