Thoughts on wet underfloor heating.

[Imtoooldforallthis]

Considering putting underflow heating in our renovation build. Had a price through our builders of 11k for 60 sq Mt's. So lots of questions, does this price seem about right, is it an efficient way of heating a house. Would you recommend it?

My Dad has it and it's great, costs are about 1/4 of ours

I have the electric version and would never do it again - if something goes wrong under our 40m2 of tiling you cannot find it to repair! Also costs a fortune

I have one big room and I find it expensive compared to the rest of the house which is radiators.

Is that wet or electric?

Wet. In the past I’ve switched it off for 24 hours and it was costing about the same a day as the rest of the house!

I have it set low and on all the time. It’s more efficient to keep it on but have the heat vary but my controls can’t manage that

In a well insulated house it's brilliant. We have it throughout the house under tiles and it's economical to run, keeps the house at a lovely ambient temperature and keeps all the walls from radiator clutter.

We have it in our house and it is brilliant and I love it. No wall space taken up by radiators and the house feels warm even if you keep it on a low level. 11k sounds pricey though. We paid about the same just pre pandemic but that included a full heating system for the whole house (5 bed) including boiler and hot water tank.

Thank you I am going to see if we can get another quote to compare.

I have it in my kitchen, and it's no trouble at all.

What flooring are you planning though?

I have the same concrete (lumpy, impossible to clean - the previous owners made a poor choice there) floors throughout the kitchen/hallway/laundry, but only the kitchen has the heating. I've had to put rugs down everywhere else because the concrete floor is so cold in winter (unbearable in bare feet - unlike the wood floor in the living room, which is fine), but the kitchen, with the underfloor heating is lovely to walk on. The kitchen would be thoroughly miserable if the floor was freezing like in the rest of the house.

We have wet underfloor heating under new extension, I really like it, it isn't burning through the oil, we've got a Nest for that bit of the house and keep it at 18.5 in the winter and it feels pleasantly warm all the time with the boiler on just a bit in the morning and evening for the rest of the house and just put it up when really cold. The cat loves it.

You need space for the manifold which is quite big.

It's very nice. Warmth drifts up evenly from the warm floor and makes the room feel perfect. It's a nicer set up than radiators, which take up wall space and give the room warmer/cooler areas.

As you have found out, it is expensive to put in. It's takes more effort and materials to turn the floor into a big radiator.

I can't see it working well with anything other than hard ceramic/stone flooring.

It takes noticeably longer to heat up a room than radiators do. If you are at home a lot and tend to leave your heating on for hours, then it will work well. If you have irregular hours and would like fast heat without a timer, it's not so good.

oh, and I think the running costs are not so different to radiators. perhaps a little cheaper.

I'm hoping i just don't understand it but we are finding it hugely expensive to run. We have big expanses of windows though. In the contained rooms (like the laundry it is lovely and warm)!

Hi op, out of interest what did the 11k include? I've been looking at wet underfloor heating covering 50 sqm in my house but I'm still waiting on someone to come and look at it. I was expecting anything up to 10k including insulating the floor underneath, but not supplying or refitting flooring on top.

What @jimjamy writes is very true.

Wet underfloor heating is great for consistent gentle heat. Works well if you have a large thermal mass in the floor with insulation underneath, and good insulation in the rest of the house.

We have it throughout our stone, single-glazed farmhouse - it's great. Not cheap to run, but nothing would be given the nature of the house. What makes it so much better than radiators is that it is pervasive as the whole floor in each room is lightly warm.

For spot heat when we need more (or in summer when the underfloor is off) we have a wood-burning stove in the living room.

It includes all the insulation, fitting and screeding ready for floor fitting on top. Area about 60 sq mtrs.

thanks @Imtoooldforallthis :)

We’ve only had ours down for about 6 weeks so we are still getting used to it. We find it expensive to run because unlike wall rads we need to have it on for 3 hours before we feel it (admittedly it’s a big floor space), so you can’t really use it to take the chill off. We find the best way with ours is to set it to 18 in the morning for 3 or 4 hours (9am to 12) it never makes it to 18 but over the next couple of hours it continues to warm up and by the evening our rooms are 20. It works well but that means planning ahead by hours… which we don’t always do. We can’t get home after a day out and stick the heat on because by the time it takes effect we are in bed, so we end up either heating the rooms for hours or leaving it off. So mixed review from us so far.

We installed an air source air conditioning unit in our conservatory. It heats as well as cools and has a 4 to 1 coefficient (we get 4kw worth of heat out of it for 1kw of electricity used). It can be set on a timer and controlled from phone. We can heat both the conservatory and the lounge if we leave the connecting doors open.

We just leave ours on at 18 (you could probably do 16) all the time which I think is the best way to do it - as with the insulation it stays at that temperature for ages without the boiler coming on and then if we do want it more comfortable in the evening than we whack it up to 19/20 and it heats up really quickly. You need I think to avoid having to heat up the whole floor space again every day...that's when it gets costly. The idea is to have it on an even temperature the whole time.

I have it in an open plan kitchen/living area . It was installed when the house was extended and knocked through. I really like it. I can't make a cost comparison because the area hasn't been heated in any other way. Insulation was installed St the same time
It's great not having radiators and the heat is a lovely overall ambient temperature- no hot or cold spots and no feeling of draughty cold air at your feet.
I am home based and it works really well as the heat is retained well during the day.

We had wet underfloor heating installed as part of out new extension, which was finished about 6 months ago.

Cost wise it was itemised as £2,900 plus vat for 28 square metres in the quote for the extension.
However there was no seperate item anywhere in the quote for the concrete floor screeding so its not clear whether this was included in the £2,900 or elsewhere. Also the extension took a long time to get from the quote stage to building (dont get me started!), so these were prices that were agreed April 2021. They may well have increased significantly since then.

We havent it had long enough to assess how much its costing to run. I do like the form of heat it produces, its a much more ambient gentle heat than you get from radiators and its much more persistent, so after it goes off at 10.30 or so it remains warm for the rest of the evening.

It does take a long time to warm up though, we find it takes an 60 to 90 mins or so from the time it switches on until the time you start getting benefit of it within the room.

As others have said, you do need to think about where the manifold will go (at 60 square metres presumably it will have a few different zones and be quite sizeable). Its an ugly looking thing so you'll have to box it in - our quote didnt include any allowance for this. It also restricts what flooring you can use, and if you have lots of rugs this will also reduce the efficiency.

We were faced with the choice of radiators vs underfloor and so far we're glad we went for underfloor.

Approx how big is the manifold, we are having a double hall cupboard making so hoping the consumer unit, boiler and manifold will fit in one half?

Hi OP

Our manifold is in a small cupboard that our decorator built for us, measuring 50 cm wide by 20 cm deep and 70 cm tall. However the size will depend on how many zones your underfloor heating is divided into. Ours is only 2 covering 28 square metres, with 60 square metres yours may well have more zones, in which case it would be wider.

If you google underfloor heating manifolds you can see examples of different sizes. Presumably when quoting your builder made a decision on how many different zones you would have and would be able to advise on how big the manifold would be.

They should also be able to advise about where it can be placed. My understanding is that it should go close to the area where the the underfloor heating is actually installed. We were fortunate that it could go the other side of our extension in our utility room and not in the extension itself. Its probably best you clarify that in advance where its going as otherwise you might find your builder takes the easy option which might not look great.

Hope that helps!

We’ve got it throughout in a house we recently moved into, so I’m unsure of the installation cost. The boiler is in the roof, and there’s a manifold in the upstairs airing cupboard and a second one under the stairs on the ground floor. It took me a while to get my head around leaving it on all day at a low temperature. I set it up like a traditional radiator system initially, so on for a few hours in the morning and then again in the evening. The house was cold. I then played around with it and realised it takes 3-4 hours to warm up the floor from cold, so setting it to on from 6am-9pm at 18° has been a lot more efficient. There are thermostats in each room so I can turn off areas we’re not using.
There’s deep pile carpet upstairs and it takes a long time to warm up there, so we’re actually replacing the carpet with something with a lower tog rating (it was knackered carpet anyway).

We’ve been in the house a few months and had an issue where a valve in the roof was leaking onto a motor for the upstairs heating. So the circuit breaker kept going off, luckily we’re in touch with the vendor who sent his plumber mate around and he identified the problem and isolated the motor quickly. I literally had no idea what the issue was. I feel like I need to do a short course on how underfloor heating works!

I have wet underfloor heating from a gas boiler and I love it. It’s the most efficient and economical heating Ive ever experienced. I have a three bed barn conversion and all the downstairs floors are stone. I have the thermostats downstairs set at 17 degrees 24/7. If I want it warmer it doesn’t take long to get from 17 to 20. The thermostats upstairs are set at 10 so the heating doesn’t come on. It is warm enough from heat rising from downstairs.

My gas consumption 1st Jan 22 to 31 Dec 22 was 817 cubic metres, or 9283 kWh. That is for heating, hot water and gas hob