Wet underfloor heating with no air source heat pump?

[bootsyjam]

Any advice gratefully recieved!
We were planning on having all electric power (we have no gas anyway) with solar panels, electric radiators and wet underfloor heating in the kitchen and bathrooms. My sister has a similar set up albeit with no underfloor heating.
She has a well insulated house, and while outs isn't now it is getting upgraded, although existing internal brick walls will most likely not be upgraded/insulated due to cost.

Was talking to the builder last week and he said that to have wet underfloor heating without an air source heat pump would be a very bad idea. He didn't really say why, I'm guessing that it would be expensive to heat? But then so would be installing an air source heat pump with all new pipes in the walls, and assuming it is installed correctly in the first place, and assuming our house will be well enough insulated to make it effective!

Are we really nuts for trying this without an air source heat pump?

We have wet underfloor heating downstairs and an oil boiler as we are rural.
We would be able to switch the oil fired boiler out for ASHP fairly easily - except that we'd need to upgrade the upstairs radiators to get the grant fo rthe ASHP adn its a very old house and a lot of upheaval involved, so we've chickened out for the moment.

Underfloor heating is great though

It will be very expensive to run if you're using electricity to heat the water. Wet ufh is also more expensive to fit than dry ufh so you're getting the worst of both worlds - high fitting costs and high running costs. What's the reason for using wet rather than dry in this situation? How are you planning to heat the water?

ASHPs are sometimes problematic in houses that aren't well-insulated because they don't heat the water to as a high a temperature as a traditional boiler, which heats the water to 60-70C. But you won't be able to heat the water for your ufh to the same temperature as for radiators because it would be too hot to walk on/damage the floor. So if you'd have issues with an ASHP you're likely to have issues with your set-up too.

I think you mean you are considering electric UFH

Unless you have more money than you know what do do with, a bad idea.

In most cases, people switch off their electric UFH the day the first bill comes in.

A heat pump can supply warmth at low cost, but I gather you won't be getting one.

Solar panels can provide useful energy on sunny summer days, so are suitable for air-conditioning. In winter, hardly anything, so will not help with heating.

Hi there, thanks for the replies so far.
So from the responses, would it be accurate to say WUFH might not actually work too well with an ASHP as it doesn't heat the water enough?
Or that it works fine with an ASHP, and that any form of underfloor heating that runs on a purely electric system with no ASHP will be prohibitively expensive?

Or that UFH is just crazy expensive no matter what you do:)))

UFH is expensive. Electricity is expensive. The combination is very expensive.

UFH can run with warm water that is not as hot as radiators and taps need. So a heat pump can supply it. Subject to the power output of your heat pump bring equal to or greater than the heat demands of your house.

If a gas or oil boiler isn't an option then you're stuck with electric heating. This is going to be more expensive whichever way you look at it. Standard electric heating i.e. panel heaters or storage heaters will have the lowest installation costs but high running costs. Electric ufh will cost more to install. If you use dry then it will cost less to install than wet with the heating supplied by some sort of electric boiler. The latter would be a very unusual set up.
An ASHP will likely be the most expensive to install but cheapest to run to a reasonably comfortable temperature.
You probably need specialist advice about what's going to work with your budget.
The worse your installation, the greater your running costs with any system.

A friend of mine installed EUFH in her house with solar panels and batteries. Aside the initial investment, the heating is really cheap to run.

Sorry I don't agree with those points: Wet UFH is not more expensive than dry electrically powered - quite the opposite.

UFH is ideal for ASHP precisely because it doesn't heat water up that hot - so a large surface area heated a bit such as a floor is fine compared with a smaller surface area as radiators have. That's why the radiators need to be bigger for ASHP - because they don't get as hot

The second!

Wet UFH is not more expensive than dry electrically powered - quite the opposite.

I said it's more expensive to fit. I agree that an ASHP is likely to be the most long-term economical way of doing ufh in the OP's case. If the house isn't well-insulated then any electric system is likely to be expensive to run.

Thanks for the replies, I forgot to add we will be adding solar panels but are not going for a battery at the moment. I don't like the idea of something that can catch fire and then be impossible to put out being in the house!