Heat pump water heater

I've been an advocate for hybrid water heaters for years. Along with hanging out your wash it is probably the most cost effective "green" step you can take. They use about a third to quarter of the electric of a standard electric water heater and the equivalent of adding four solar panels to your house. For some of us they have the added benefit of dehumidifying (and cooling) the space where it is located. You also need to be able to have a place for the drain hose to go. For us it is a five gallon bucket that we empty every two out three weeks. Depending on the confines of your space it may not be ideal for you. Most of this is probably not new to you.

 

We were offered a FREE (100% including installation) heat pump water heater from our state. Of course, I signed up. But after 3 months of waiting a contractor showed up with the unit and quickly determined that they could not install it in our house. We have an oil-fired boiler that heats up domestic hot water as well as whole-house heating via baseboard-type radiators. The conversion from an oil boiler to an electric water heater was not possible without major renovation in our small utility space where the current boiler sits and upgrading the electric main panel.

So I abundant the idea, at least until I decide to take it up on the upgrading of the electrical panel and renovation of the house. But in afterthought, I realized that even if they could have installed the unit, the heat pump water heater would have been more expensive to operate than oil fired boiler in our area with the very high electricity rate and relatively low oil price.

 

First, the typical heat pump water heater is a bit taller than other water heaters. One would not fit into my basement, which is about 5ft from floor to ceiling. Before going forward, figure out if it will fit. They also need more space around them for airflow, though is more a concern for installations in closets.

Basements tend to hold the same temp year around, and generally aren't directly heated. The HPWH drawing heat there shouldn't have a big impact of home heating in the winter. Cold floors can be addressed by insulation. With ducted units, it could be possible to direct output to the living space during the summer.

Mini-split units do exist that collect heat from outside. This addresses the space issue of the tank, but dehumidifying is lost. Their biggest drawback is cost. IIRC, one I found that used CO2 refrigerant was $5000.

 

You've got me curious- I've had a contractor come out to estimate the same type of conversion from the same type of oil-fired setup. They didn't suggest any particular complications. Mind you I have already modernized my electric panel.

But nobody seemed to think it would be a big deal to set up a HPWH next to the oil furnace and put a couple of valves in to let me switch from one to the other.

We don't intend to remove the oil system yet, since it can be run by our emergency generator where the heat pump is just too demanding.

 

My dryer dehumidifies the wet clothing basket air instead of heating utility room air and dumping hot, humid, expensive air out a vent. The dryer has no vent and works perfectly fine in the summer when I have left the outside door cracked open to let the small amount of waste heat out.

The hybrid hot water heater cools the utility room ... much appreciated in hot weather. When it gets too cold, it reverts to resistance heating. But living in North Alabama, we rarely get more than a couple of days below freezing.

The installation and owner's manual shows adding ducting to draw hot air from other spaces and releasing cold air into another duct. There is a realistic probability I may add ducting between the utility room and separator wall with the TV room for auxiliary A/C during the long warm periods in Alabama.

Bob Wilson

 

We have had a Heat Pump Water Heater for going on 10 years now - ours is located in the basement which is ideal for us.

I would recommend you read this article and look very closely at the specification for location of these units - they are located on the water heater or manufactures website as shown in this article. These units do typically generate condensate.

I would also say an important consideration is that these units pull large amounts of air through a filter and then through condenser coils. The filter requires cleaning every so often and a filthy environment of any kind will cause problems with the filter and eventually the condenser coils plugging up. Wherever you put the unit keep in mind you will eventually and periodically be climbing or crawling into the area to change/clean the filter assembly.

Where to Install a Heat Pump Hot Water Heater In Your Home - Attainable Home

 

Does this mean you've sprung for one of the newfangled heap-pump dryers?

I like the idea. But then pretty much the only time I run my dryer is for towels or pillows and such. Other stuff dries easily enough by hanging.

 

I've come to understand that using CO2 as a refrigerant requires significant overbuilding in the compressors due to the higher relative pressure involved. I can't find it now, but I'd read about a scheme where a German company wanted to leverage the skills and experience of high performance engine builders to manufacture these tougher compressors.

 

We also have a heat pump dryer in our in-law quarters which we have rented. We still have our gas dryer, but similarly to you only use it a very few times a year. We almost only use our solar/wind dryer.

"Newfangled...." We had one while living in Germany in the 90's.

 

Yeah, that was what the contractor had in his mind before seeing our house and where the oil boiler and electrical panel were. When applying for the FREE heat pump water heater, the only two home requirements they listed were: 1) Basement space with a 6-foot ceiling and 2) Water heater in the basement. Ours cleared those two requirements. They approved the application and arranged for the contractor to install a new heat pump water heater without making a pre-installation site visit.

In our house, the oil boiler is sitting in a corner of the house on the lowest level which I considered to be a "basement" within a utility closet where the boiler and a 50 gal hot water tank are. Since there is no existing electric water heater there, there is no 220V outlet there. The main panel is located in the other corner of the house the furthest away from where the boiler room is. And, the entire "basement" is 100% finished with flooring, walls, and ceiling. Actually, it is probably not considered to be a "full basement". It is a partially earth-bermed house. One side of the foundation is completely below grade bermed by earth, but only half grade on two sides and at grade level on one side as typically found in a raised ranch. Due to this configuration, even if the panel gets upgraded, pulling the wire to the other corner of the house would require knocking down walls, and ceilings through multiple rooms. Not the job ordinally plumber/electrician would tackle.
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Gotcha.

Fortunately I don't have to stretch any definitions.

The only needle I'm trying to thread is maximizing the tax rebate.

Next year we will enjoy an $2,000 federal tax credit for the heat pump I had installed on Wednesday. Then we intend to install a second heat pump (for a different area of the house) in January, to get a similar credit in the following year.

It is not clear whether we can claim the credit associated with a HPWH in the same year that we claim credits for either of the HVAC systems. And I may need to put it off anyway, plenty of other upkeep & expenses...

 

New IRA and associated tax laws seem to separate an HPWH and house heat pump for tax credit purposes. But in our case, if successfully installed, HPWH would have been FREE, so no tax credit consideration there. I haven't paid income tax for the last 4 years out of 5 using the EV tax credit effectively canceling all of my tax liability. I have not done anything this year for the tax credit yet. Solar panel with battery storage is likely to be the most bang for the buck for us. Even though with the new program, we can now qualify for a whole house heat pump rebate/tax credit up to $10,600, it is not a cheaper option for us for it will cost close to 30% more on operating costs compared to keep using the aging oil boiler.

 

Resurrecting an old thread.

Our home have been slowly moving away from fossil fuel dependency. We installed 15kW solar, then replaced the oil-fired boiler central heating with heat pumps. That alone reduced our annual heating oil consumption by about 500 gallons. Unfortunately, our hot water still uses the oil-fired boiler (see my quoted comment from 2023. We could not do the electric conversion with a hybrid heat pump water heater then. But I am in contact with an installer of solar assisted heat pump water heater now. If all goes well, that will reduce our oil consumption by additional 250 gal.

Anyone here has experience with this technology?

Switching to a BEV and ditching our plug-in hybrid eliminated gas needs for our transportation. That was roughly 120 gal of gas/yr eliminated.

After home heating, water heater, and automobile, next big ticket item is a back-up generator. We use on average about 50 gallons of gas per year for the generator for multi-days outage. But the cost of converting the gas generator with battery and solar generator is now too expensive without the 30% tax credit.

BTW, I still own a few small engine yard tools that requires gas. Some are just not replaceable with electric, like chainsaw, tiller, and chipper. But at moment, they are not my priorities. Those tools collectively use less than 10 gal of gasoline a year total. They are just too low impact to prioritize.

 

I don't have experience with the solar water heater.

...but you mentioned additional projects ...

We purchase a Samsung Ventless Heat Pump Clothes Dryer in November, and it made a big impact on our electric bill.

One of the most overlooked features of a Ventless Heat Pump Clothes Dryer is that in the winter it is not pulling out and exhausting your homes heated air and then pulling in cool air from outside the home to replace the exhausted conditioned air -... and vice versa in the summer.
A clothes dryer exhaust system can remove up to 200 cu ft/minute of conditioned air from the home - if the dryer runs 60 minutes that's 12,000 cu ft of conditioned air removed from you home that you have paid to condition and 12,000 cu ft of outside replacement air that had been pulled into your home that you must now pay to condition.
It might make economic sense to investigate that if it fits your lifestyle.

We do have a hybrid heat pump water heater and it made a tremendous difference on the energy bill and am sure your solar water heater project will do the same!

 

Thanks for the info on the heat pump dryer. I have not researched much yet, because it is not yet widely available from all brands. LG and Samsung seems to the only brand readily available in the US. But certainly, when it comes to time to replace our cloth dryer, I will look into it. We switched oven-range to IH, but that did not cut electric bill much. Our cloth dryer sit in a unheated utility room separate from our main living part of our house, so vented or ventless I don't think it affect the house. But lower electric consumption is always a good thing.

As for the cost comparison, unfortunately in our region, in general, the conversion from fossil fuel to electric does not save. One estimate given by an installer of the solar assisted heat pump water heater is about 2000kWh of electricity for a year. That is $780 a year at our current electric rate of $0.39/kWh. Compared to that oil-fired boiler uses about 250 gallons of heating oil. At average cost of $3/gal, it cost $750 a year. But... At moment, oil price has increased to $5/gal, so yeah, if it stays that high, I will save $470 annually. But, even with that saving, it will take more than 10 years to recoup the initial cost.

 

No experience, but it isn't new.
When I first looked into heat pump water heaters, there wasn't anything available in the US, but did across an Australian company selling these solar water heaters. So they have been on the market for over a decade now.

 

Although I had not seen or heard of the system until recently, my understanding is that system has been available and widely used in Europe. On paper it is as efficient or better than the hybrid heat pump water heaters which are now widely available in the US. COP 3.5 to 5.0 are usually listed.

What makes the system attractive for me is that with the evaporator installed on outside, I think it can be installed in a very small utility room in living space of the home (i.e. not in largely empty basement) without causing surrounding area getting cold. That limitations caused the regular hybrid heat pump water heater no go in our home 3 years ago.

I'm hoping this system will allow the conversion without costing us for the major addition/renovation to our current home.

 

I'll look into it when it is time for a new water heater, as the current ones are too tall for my basement.

 

I went with:

• Front loader washer - less water and energy
• Ventless driver - lower electricity, 120 VAC, and heat/AC loss
• Stacked - less floor space

Bob Wilson