Please, someone, tell me how to work the underfloor heating!

[Catabogus]

We had (wet) underfloor heating installed in a new kitchen 2 years ago. The installers told me it’s best to leave it on low all the time, so we tried this for a few months but the gas bill seemed to be through the roof. So I changed it to come on for a few hours in the early morning and a few in the evening, winter only (same as the radiators in the rest of the house, in fact).

Was this the right thing to do? I’m asking because last winter our kitchen seemed freezing over breakfast, even when I’d set it to come on at 4am and we weren’t eating until 8am. It was set to 18 degrees but the thermometer was telling me our kitchen was rarely above 15 degrees!

What am I doing wrong? Do I need to go back to having it on all the time? I can’t escape the feeling this is really wasteful and expensive - but also can’t face another winter of shivering in 2 jumpers while eating our toast.

Basically, if you have underfloor heating, please tell me how you set it. Thank you!

@PigletJohn

is the floor (under the tiles) wood or concrete?

Concrete

@Stiltonlover

We have porcelain tile flooring. The room is quite well insulated although big windows/skylights must let some heat escape. It’s a big room with a high ceiling in case that makes a difference.

This sounds exactly like our kitchen, and it's the warmest room in the house! So something definitely isn't right - have you ever had a plumber round to look?

No - is that what we need to do? I do resent paying for a plumber if it’s something I can sort by just adjusting the timing. I may have to take the plunge though if we can’t figure it out.

We have ufh in kitchen extension and it is great. We have on in the winter, on a timer not all the time. It is on longer than rads would be though, somthing like 5am-9am and then 3-8pm. As a new room it is well insulated and holds heat well but it does take a while to heat up, hence coming on at 5am!

Did the builder properly insulate when installed? We had full insulation where it was new build but only minimal in the existing hall and it is much colder.

We had underfloor heating in one room. It felt lovely. Then we got a smart meter. I checked it with & without the UFH on. It used a frightening amount of electricity compared to everything else in the house. A couple of hours of it cost way more than a couple of days of gas central heating. I was sad, but had to be sensible and stop using it 😔

Is the thermostat in the same room saying it reaches 18 degrees? If it cools down to 15 degrees it will need several hours to get up to 18.

We have rads on separate controls in rest of house and from my experience the ufh does need to be on longer, but we haven’t found our overall bill increased.

I think elec ufh def more expensive but not necessarily for wet ufh.

It's all in the thermostats. We have it in most of downstairs and a thermostat for each zone. It's on all the time but only triggered by the thermostat ( which is up high) when the air temperature drops. We have ours set to 18 mostly. 15 if we're away. So on all the time but thermostat low. We have multi fuel stoves for evenings etc.
Our are wireless thermostats. Check the batteries of you have similar because no signal means it just keeps on heating.
If it's never worked properly then you might need your system balancing. Get someone on for that

You can vary the target temperature on the thermostat over the day btw. So ours is set for 16 overnight then 19 from the time were getting up and out then up again in evening. But the system is on all the time just not being "called" by the thermostat

@OnceUponARainbow

Is the thermostat in the same room saying it reaches 18 degrees? If it cools down to 15 degrees it will need several hours to get up to 18.

We have rads on separate controls in rest of house and from my experience the ufh does need to be on longer, but we haven’t found our overall bill increased.

No, the thermostat says something like 14 or 15 degrees (and confirmed by thermometer)!

@OnceUponARainbow

We have ufh in kitchen extension and it is great. We have on in the winter, on a timer not all the time. It is on longer than rads would be though, somthing like 5am-9am and then 3-8pm. As a new room it is well insulated and holds heat well but it does take a while to heat up, hence coming on at 5am!

Did the builder properly insulate when installed? We had full insulation where it was new build but only minimal in the existing hall and it is much colder.

Those timings are exactly what I tried last winter - but in the mornings it never got above 15. In the evenings it was usually a lot better (but then we were cooking in the kitchen and it would be generally warmer).

It should be all insulated properly, yes. We asked for it to be as well insulated as possible.

@Catabogus

Concrete

Then it will take several hours to warm up and (roughly speaking) about as many to cool down

Wnen winter draws on, experiment by timing it to come on at 4am, and see what the room is like at 8am

Time it to go off 4 hours before you leave the house or go to bed.

4 hours might not turn out to be correct, but try it, and move forward or back half an hour at a time.

If you are heating it every day, it will not be so cold to start with, so after the first week you can reduce the heating time.

@AnnieSnap

We had underfloor heating in one room. It felt lovely. Then we got a smart meter. I checked it with & without the UFH on. It used a frightening amount of electricity compared to everything else in the house. A couple of hours of it cost way more than a couple of days of gas central heating. I was sad, but had to be sensible and stop using it 😔

This is quite typical for people who have electric UFH installed.

[quote PigletJohn]@Catabogus

Concrete

Then it will take several hours to warm up and (roughly speaking) about as many to cool down

Wnen winter draws on, experiment by timing it to come on at 4am, and see what the room is like at 8am

Time it to go off 4 hours before you leave the house or go to bed.

4 hours might not turn out to be correct, but try it, and move forward or back half an hour at a time.

If you are heating it every day, it will not be so cold to start with, so after the first week you can reduce the heating time.[/quote]
Lovely clear advice - thank you! I know from last year that having it come on at 4am would still mean it was nowhere near 18° by 8am. So presumably I should try 3am?

And when you say it should go off 4 hours before I go to bed, you mean it should be on all day from (say) 3am to 7pm, if I go to bed at 11pm?

What temp is it before it comes on? Eg if it is 13 degrees then I’m not too surprised if it is only getting to 15 after a few hours. We find it takes longer to warm up in the mornings than evenings, like you said.

I remember when we went away one half term and switched it off completely, I checked the temp via hive and it was 13 degres, we like 20 and it took about 8 hours to get to that temp!

@OnceUponARainbow

What temp is it before it comes on? Eg if it is 13 degrees then I’m not too surprised if it is only getting to 15 after a few hours. We find it takes longer to warm up in the mornings than evenings, like you said.

I remember when we went away one half term and switched it off completely, I checked the temp via hive and it was 13 degres, we like 20 and it took about 8 hours to get to that temp!

Oh, interesting! Yes that is exactly like ours.

I expect it has some kind of thermostat to turn it down as the room warms up. I don't know much about UFH, but it has a blending valve to cool down the water circulating in the floor, and a room thermostat and a timer as well. There may be some juggling required.

If the person who installed it was skilled in UFH, they should be able to provide operating instructions. You haven't put down rugs and carpets, have you?

@PigletJohn I didn’t know there was any other kind!

Energy from elecricity costs around four times as much as energy from gas.

I just checked the price per kWh that I am currently being charged for gas and electricity. Electricity is 5.6 times as much.

Your tariff may vary.

@Catabogus we have wet UFH and we have experimented with it to find what works for us. Having it come on and off is expensive ime it takes a while to heat up so uses more gas etc. We found the best thing was to set it at a constant temperature and if it dips below it will fire up. I tend to set ours to 16 degrees from 18.30 with a nudge up to 18 degrees from 4.30am. Ours seems to retain the heat well so we don't find it fires back up at 4.30am all the time usually only if it's very cold. Ours is a large space with a lot of glass so we find it takes a few days when switched on to "settle". Feel free to PM if I can help.

@PigletJohn

I expect it has some kind of thermostat to turn it down as the room warms up. I don't know much about UFH, but it has a blending valve to cool down the water circulating in the floor, and a room thermostat and a timer as well. There may be some juggling required.

If the person who installed it was skilled in UFH, they should be able to provide operating instructions. You haven't put down rugs and carpets, have you?

No, no rugs or carpets. And in theory yes we should be able to get hold of the installer, but in reality they’re a big building firm who are booked up until about 3 years from now and don’t prioritise answering the phone!

[quote mommybear1]@Catabogus we have wet UFH and we have experimented with it to find what works for us. Having it come on and off is expensive ime it takes a while to heat up so uses more gas etc. We found the best thing was to set it at a constant temperature and if it dips below it will fire up. I tend to set ours to 16 degrees from 18.30 with a nudge up to 18 degrees from 4.30am. Ours seems to retain the heat well so we don't find it fires back up at 4.30am all the time usually only if it's very cold. Ours is a large space with a lot of glass so we find it takes a few days when switched on to "settle". Feel free to PM if I can help.[/quote]
This is helpful - thank you! I might give this a go.

Yes behave wet ufh in two rooms (extension), both have their own thermostats. Love it.
As others say, it’s on low constantly. I nudge it up on really cold days and it responds quickly.
I don’t have rads in those rooms, no need.

I have electric ufh in one room, I knew it would be expensive but chose comfort over cost.
It does take several hours to get fully up to temperature but once it does it's lovely.