Home Assistant is great for power management

Posted May 18, 2025 8:40 UTC (Sun) by Wol (subscriber, #4433)
In reply to: Home Assistant is great for power management by marcH
Parent article: A kernel developer plays with Home Assistant: case studies

> For the simple reason that every house must have a water heater anyway, and that many already have an electric one.

Except that's a non sequitur. Just because you have a water heater, doesn't mean you can turn up the storage tempature - most European installations no longer have hot water tanks.

Pretty much all new European installations are "on demand" combi systems. Although they're now slowly being replaced by heat-pump systems, which brings back the water tank.

Cheers,
Wol.

Home Assistant is great for power management

Posted May 18, 2025 11:00 UTC (Sun) by zdzichu (subscriber, #17118) [Link]

Actually, most Europe use central heating with heat generated in cogeneration or other centralised heat plants.

Damn, I've took the bait and answered to Wol's comment :(

Home Assistant is great for power management

Posted May 19, 2025 10:01 UTC (Mon) by paulj (subscriber, #341) [Link] (6 responses)

UK and Ireland surely are still water tank? Lived in a new build in 2016 which had a big water tank, could be heated either by gas or electricity.

Home Assistant is great for power management

Posted May 19, 2025 13:15 UTC (Mon) by excors (subscriber, #95769) [Link] (5 responses)

No, in the UK reportedly 80% of all gas boiler sales are combi boilers, which provide hot water on demand with no tank (https://www.gov.uk/government/consultations/raising-produ...).

I think system boilers with tanks are mainly recommended for larger homes, because a combi boiler won't have enough power to supply more than 1-2 bathrooms simultaneously, but otherwise combi boilers are preferred since they're more energy-efficient and save space. (But much less efficient than heat pumps, which do need the tank.)

Home Assistant is great for power management

Posted May 19, 2025 15:16 UTC (Mon) by Wol (subscriber, #4433) [Link] (3 responses)

If you want a boiler, it's actually very hard *not* to have a combi.

We had our "gas fire and back boiler" replaced shortly after moving into our current home 25 years ago, and were lucky as they were in the process of banning them. Then maybe 10 years ago when heat-pumps were "new" I had one put in, but unfortunately I think we fell foul of the cowboys, and when it broke down we couldn't get it repaired, so combi was about the only option we had.

(That broke too, and our boiler guy had disappeared, a family friend of all people, so that gave us grief, too ...)

Cheers,
Wol

Home Assistant is great for power management

Posted May 19, 2025 16:22 UTC (Mon) by knewt (subscriber, #32124) [Link] (2 responses)

> If you want a boiler, it's actually very hard *not* to have a combi.

So late last year my absolutely ancient, totally energy inefficient traditional boiler failed.

Now, if I had been sorting out a replacement on my own schedule, I would almost certainly have replaced it with a combi. That was always in the plans. However, this was at a time of year where I certainly needed something quickly. And such a combi replacement would have required a *lot* of extra installation time, because there is no mains water anywhere near the boiler, and there is no (currently accessible) gas anywhere near the mains water. And I'm a mid-terrace, so can not just run pipework around from front to back.

Could have covered the extra cost, I had plenty budgeted away for an eventual boiler replacement. It was the time issue, plus getting someone in. I very quickly came to the conclusion that I would need to replace with another traditional boiler. Which was disappointing, but hey, what can you do. At least it's a *much* more energy efficient unit now! And due to being a much quicker process, I was able to get someone in less than a week after it failed. Failed on a Wednesday, was replaced the following Monday.

Home Assistant is great for power management

Posted May 19, 2025 16:52 UTC (Mon) by Wol (subscriber, #4433) [Link] (1 responses)

> At least it's a *much* more energy efficient unit now!

And if it's replaced the existing unit, at least the waste heat is probably warming your house (nice in winter, less so in summer).

One of the drives - aiui - for combi boilers was EU regs based on the assumption that the boiler was located in a non-living area of the house (basement, loft, whatever). Most UK boilers were in the living area - we had a back-boiler in the lounge - so much of the "wasted" energy provided extra heat in our main room ...

Cheers,
Wol

Home Assistant is great for power management

Posted May 19, 2025 17:15 UTC (Mon) by knewt (subscriber, #32124) [Link]

It's located in a hall cupboard next to the front door (along with the gas & leccy meters), so *possibly* a little bit?

Home Assistant is great for power management

Posted May 19, 2025 16:00 UTC (Mon) by paulj (subscriber, #341) [Link]

Interesting. The 2016 new-build was in a part of the UK with larger homes by default (Scotland, land is much cheaper there than England for a start), so maybe that's why. Current house is older, so it has the typical immersion heater water tank (electric, and circuit also goes past the back-boiler on the fire-place - Irish houses were typically coal/peat fire heated till around the 80s).

With domestic solar it can make a lot of sense to have reasonably decent hot water storage, so perhaps that trend away from electric water tanks will change.