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Comment by infecto | Hacker News Reader

The OP did a bad job but here are my guesses.

Most traditional UK homes do not have central air, they use boiler/radiator systems for the winter. Retrofitting these homes do have central air with a heat pump probably does not make sense.

I don't think the product the OP linked was a very good example either. It's just an electric boiler that somehow stores offpeak energy to be used during the day. Don't know a lot about boiler systems but I cannot imagine these are that revolutionary and there are other similar systems out there, it is just an electric boiler with a smart energy/battery storage system to capture the off peak energy...seems like you could do something similar with a standalone electric boiler and a battery backup system.

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No, that isn't accurate. Air to water heat pump systems can be incredibly efficient and effective, even if the insulation isn't great. Flow temperatures are usually lower than gas boilers, so sometimes radiators need to be upgraded to larger ones but with a good quality heat pump and proper setup (weather compensation being a big one) there actually are few problems.

There is a huge education gap unfortunately, since there are grants to install them so you get dodgy installers doing crap jobs. Even with a high quality heat pump, if it's not set up correctly you can get COPs as low as 2.5 or so and pay more than having gas. There are some good channels on YouTube of people with the proper training making fairly minor changes to these systems and acheiving SCOPs around 4 which is cheaper than gas.

I think you are replying to the wrong thread? I never argued that they would never work, I am a big proponent of heat pumps. Just taking a stab at why the OP thinks they are not good for UK. Retrofitting older UK homes probably takes more steps than what the government grants are providing.

Thanks for the information though.

Heat pumps work perfectly fine with radiator systems.

They do indeed, same with heat pump style water heaters used in America.

Can you link a drop-in heat pump replacement for my Vaillant gas boiler mounted in tiny apartment bathroom, which heats the radiators in the winter but also provides hot water year-round?

Talk to your local gas/water/heating instalation company, they are the experts.

Yes. For example Daikin Altherma, but I'm sure that every brand has a compatible system

It seems like it requires an external unit. I cannot easily mount an external unit. The bathroom is far from external walls, boiler is connected to the shared air intake in the wall that leads to the roof. So this doesn't look like a drop-in replacement.

Outdoor units are pretty flexible in the sorts of places they can be mounted and the insulated refrigerant lines can be run to the interior of buildings fairly easily. Don't just assume a solution can't work until an expert says no.

And even if you can't hook into your existing radiators wall mounted mini splits don't require extensive interior changes to function (plus you get cooling as well)

I do have a mini-split AC which can also provide heat. It is OK for autumn and spring but it is a no match for a radiator heating when it's really cold outside in the winter. Yes, of course I can run the lines through the whole apartment but this is a much costlier proposition.

Thermal storage bricks are a lot cheaper than batteries and chargers. The bad part is that it's resistance heating, which throws away a lot of exergy.

Agreed! I just said battery to cover any type of energy storage mechanism.

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