Heat Pump Water Heaters - any experience?

Bendy_House

These are new to me. They are water tanks with a built-in heat pump (like a fridge in reverse).

They are designed only to heat this tank for DHW use, not to provide actual room/house heating.

https://www.energy.gov/energysaver/heat-pump-water-heaters

Any idea of cost? Effectiveness? Worth it?

Cheers.

BUFF

No personal experience but strangely enough yesterday i was reading a blog from a guy in the US waxing lyrical about them.
https://cleantechnica.com/2020/04/26/heat-pump-water-heaters-game-changers-in-efficiency/

Bendy_House

Ha-ha - that's the same link I was sent by my bro!

Gerry1

> "Heat pump water heaters require installation in locations that remain in the 40º–90ºF (4.4º–32.2ºC) range year-round."

Good luck with that if you're a right-ponder...

BUFF

Bendy_House said:

Ha-ha - that's the same link I was sent by my bro!

Actually that may not be the link as the one that I read mentioned how high  a % (majority) of water heater installs in Maine & another state  ( Iowa or Oregon?) were HWHPs & neither is a warm state! Of course the water heater tends to be inside the building so hopefuly above 4C.
Like ASHPs they do have a backup (electric element) & can run in hybrid mode or on the element only.

QrizB

I came across them last year.

Looks an interesting idea if you've got electric heating, and in the summer you get local cool air as a possible bonus.

More expensive to run than HW from GCH, though, uness you've got much cheaper electricity than most do.

Reed_Richards

The question that always worries me is why you would want to heat your hot water with a heat pump but heat your rooms with something else.  If you heat with wood or coal in ordinary stoves or fireplaces (without a back boiler) then a hot-water-only heat pump might come in handy.  Otherwise I don't know.  

Bendy_House

Absolutely, RR.

I'm really just trying to become as informed as possible, with my bro having to look at a new heating/energy method in his home. Pretty much a blank slate, although there are rads currently fitted, so changing to UFH, unfortunately, would not be cost-effective.

This HP DHW was just something he came across and asked me about. I hadn't heard of them before, so was curious.

No, if he goes biomass with its thermal store, it wouldn't make any sense at all. Cheers.

Gerry1

BUFF said:

Bendy_House said:

Ha-ha - that's the same link I was sent by my bro!

Of course the water heater tends to be inside the building so hopefully above 4C.

Not sure that's valid because you'd be heating your hot water by sucking expensive heat from your room.  You'd be robbing your own till.

Bendy_House

Yes, it would have to be a room with a naturally adequate temp, or possibly even one that would benefit from being cooled in summer months

BUFF

QrizB said:

I came across them last year.

Looks an interesting idea if you've got electric heating, and in the summer you get local cool air as a possible bonus.

More expensive to run than HW from GCH, though, uness you've got much cheaper electricity than most do.

As an example it looks like current domestic electricity costs per kWh in Maine (which apparently is an expensive state, 33% above average) is ~ 1/2 of our SVR rate & I don't know if they even have a standing charge (edit; they apparently have "delivery charges" which I guess are a similar idea)

.Reed_Richards said:

The question that always worries me is why you would want to heat your hot water with a heat pump but heat your rooms with something else.  If you heat with wood or coal in ordinary stoves or fireplaces (without a back boiler) then a hot-water-only heat pump might come in handy.  Otherwise I don't know.  

US heating systems are traditionally quite different from the UK's - wet/hydronic ch (our norm) is relatively rare there. The majority of US household systems are ducted warm air.