[moooo99]

It does. However, the hotter the water becomes, the less effective the heatpump becomes. With anything beyond 60C becoming very inefficient.

With hot water tanks, they are unfortunately pretty badly insulated as well, with some of them loosing heat very quickly. Depending on how you plan on using that water, you also have to make sure the temperature never dips below ~60C to avoid legionella from spreading.

I actually think that heating your home slighly higher than you‘d usually do is the simplest and most effective approach, assuming it is properly insulated. Just rise the target temp for 1-2C when the energy is cheap and reset it once it isn‘t. Probably not as efficient, but extremely simple to implement.

[ProllyInfamous]

I have two heat pump water tanks, one Rheem and one AO Smith (our local utility heavily-subsidizes these, with a net-cost less than a standard tank water heater).

They both are rated for annual kWH usage less than the US EPA yellow label can display (for their category of tanked water heaters, i.e. competing mostly with resistive heating models).

Annually water heating is about 3% of my energy consumption.

[stratosmacker]

Do you prefer one to the other? I’m in the market

[IneffablePigeon]

The legionella thing is a little overblown fwiw. 50 degrees is perfectly adequate, and you can go lower with very little risk if you set it to briefly bump up to 60 every week or two. Even that is not hugely necessary in a domestic setting.

https://www.heatgeek.com/articles/legionella-and-water-tempe...

[moooo99]

This is a heavy depends. Primarily on how well insulated throughout your home your waterlines are and how frequently they are used.

If you only have 50C in your tank and badly insulated lines, your temperature can dip below 50V very easily where legionella feel really comfortable.