I have one of those and it really isn't the same as AC.

I trust that you mean it doesn’t have the same effectiveness as other AC units you’ve used.

From a pedantic point of view, it is quite literally the exact same as an AC. Air conditioners are literally heat pumps.

Air conditioners are heat pumps. Not all heat pumps are air conditioners.

Common installations reuse the wet systems we have and are air to water, which was until recently the only thing the grants covered (and now it’s still lower for a2a).

And AFAIK the grants still don't cover something that can also be used as an AC, though maybe that's changed.

I have one and it is? We keep our house very cool in the summer using it and it works just as well as an in window AC that we use in the bedroom. Maybe what you have is different somehow.

An AC is literally a heat pump

So is a refrigerator; all the other considerations make saying "I have a heat pump therefore I have AC" in this context a bit like a Mexican saying "I am American".

Like, sure, but the word has a specific and a general meaning, conventional use is only the specific meaning.

How is it not the same?

Look, I know that actuuuualy and technically it's the same type of technology working on the same principle. The thing I have ( Daalderop 5G WPU) mainly works as floor heating (and great at that), but it's the size of a fridge and has it's own utility closet and a pipe underground for whatever thermal medium it uses and it's own separate meter (for reasons of regulatory kind). And it's a district wide deployment where I don't even own the thing.

Most importantly it's not the same in the way of me not feeling the chill. It's stupid, as I know the house is cooler than the outsides, but the actual split system delivers the cold air right to where I feel it and this thing just makes the ambient temperature down to 25c without me even noticing.

I don't want to know what it costs to install (I got it with the house), but split system costed lol nothing in eastern european dollars and took some guys less than half a day and zero permits to install too. For better or worse the heat pump doesn't live in the same locale I had that.

A water/water heat pump is absolutely not the same thing the other commenters are talking about. They're mostly talking about an air/air heat pump, where it's literally all the same parts but has a reversing valve so it can either be hot/cold or cold/hot among the coils with fans blowing through them.

This is more like what they're talking about, but they do come in a lot of shapes and sizes and can be more or less integrated into central systems.

https://senville.com/mini-split-heat-pumps/

It's almost like there is more than one thing called heatpump

UK typically uses air-to-water heat pumps with convection radiators. The passive radiators are useless for cooling, and condensation on pipes in walls can be a problem.

With a heat pump asked central heating system run in cooling mode condensate can form at your pipes in the wall and your radiators or floor when using under floor heating. So you have to limit its cooling power to prevent that.

With an AC the advantage is that the condensate is forming inside the AC when cooling the air.

I guess the issue is that American heat pumps use central air handlers. There is a coil inside and outside the house a fan that blows air across each coil. The inside fan pulls air from around the house and then blows hot or cold air through vents. It sounds like British heat pumps just push hot water through pipes. We use insulation over the refrigerant pipes to prevent condensation from forming in the walls. The length of the run is also kept as short as possible to reduce losses.

Most British homes haven't been built to support AC. Retro-fitting a heatpump for heating is relatively straightforward, as the heating delivery mechanism (pipes to transmit hot water to wall-mounted radiators) is already in place.

Although you could pipe cool water through the radiators, it's an ineffective form of cooling compared to blown-air systems, and retro-fitting a blown-air system is much more costly than a heating-only heat pump.

You can't pipe cold water through radiators, all you'll get is a very wet floor. Think of an ice cold bottle of beer.

You need a radiator with a built-in electric fan, this will all but eliminate the condensation.

However it will not cool like an A/C unit, only something like 5°C reduction. This can be enough to get a decent night's sleep during a summer heatwave.

We're talking about retrofitting to existing typical UK radiators. If I was buying new radiators (and paying an electrician to run electricity to them!) then I would want a better return on investment than cooling from 35C to 30C.

I visited a building once that had "cold panels" covering about half of the drop ceiling. Supposedly they made a difference in summer but I suppose they needed the massive surface area.

You can't just pump the cold water through the heating elements, because of condensation. The correct installation, requires special heating, cooling elements that include fans (it helps with the cooling) and drainage for the condensation.

I have "cooled floors", so basically heated floors but you can reverse the circuit in summer. Condensation really isn't an issue unless the temperature difference is massive, say room temperature being 28 degrees C and then kicking the system into high gear trying to get to 20 degrees C.

Once room and floor temperature match, condensation doesn't occur anymore as long as you keep it running.

I've had a cooling/heating heatpump fitted. Adding a couple of wall units bumped the price by about £1500, although the whole thing was softened by the grant for getting rid of an oil fired boiler.

While our house is relatibvely small and we kept the units (which also do heating as well) confined to the main living space, it wasn't especially burdensome. The bulk of the work was installing the behemoth of a hot water tank!

Did you consider going with instant hot water at the sink/basin/shower/bath? My house is also relatively small and has little room for a huge hot water tank.

That can’t practically be done electronically. Needs to be gas. The power demand is too high for electric water heating

Original comment mentioned £ so they are in the UK. It's possible and not super uncommon to have electric showers in the UK because the 230V provides enough power for water heating unlike the US.

I'm currently investigating options for kitchen sinks and such. It feels quite silly to have a long length of pipe leading from a central source for a small amount of warm water to wash my hands.

Boiling water taps like Quooker and similar are pretty good.

There's a limit: you can fill a medium saucepan with boiling water, but large/industrial-kitchen pans will exhaust the boiling water and you'll need to wait for the next batch.

It's fine for general household use.

Belatedly, no, but I think our installer may have (possibly as a result of the free money!) wildly overspecified the tank which I suspect we will never empty even if we actually tried.

Daikin (and presumably others, but they're the ones we went with) do have integrated tanks/heatpump internal units. It might be worth having a think about your actual needs and it may be that there is a solution.

My experience with electric hot water taps is that they've been universally awful and only a last resort, but equally the state of the art may have moved on since I last looked!

They can be, and in many places that get both too hot and too cold they're built that way as standard, but in places that are usually too hot or usually too cold, they're often built one way to save a bit of complexity.