zlacker

I don't know what it's like where you're living but here in Switzerland it's completely normal to have one heat pump that does both. Here there's a lot of floor heating, which also uses water, so you usually just run one loop to the "boiler" (a water tank with a copper loop for the water from the heat pump to circulate through) and one through the floor and have a valve to switch which is running through the heat pump.

I have one of these: https://cta.ch/en/private/products/ah-i-eco-innen

I got it in October so most of the time I've had it has been <10C. It's produced 806.3 kWh of heating for hot water and 6587.2 kWh for the floor heating. It consumed 302.7 kWh and 1801.4 kWh respectively, for a COP of 2.66 and 3.66.

>>Youden+(OP)
That's a different kettle of fish entirely, largely because with the heat pump water heater they're pulling the heat from the inside of your house, forcing you to move it twice when it is cold out. With a combined unit you only move it once, as the other side of the unit is outside.

That's why they're so great for warm climates though. The water heater also cools your house, especially as that heat is then lost down the drain. Everybody in the south should be jumping on these.