has anyone got underfloor heating?

I don't have underfloor heating in my house but I design UFH systems for a living! The cost would depend on the floor construction of the house. Timber joisted floors are more expensive to retro-fit but a lot less hassle than digging up an existing concrete floor! You can get overlay systems but they still raise the floor level by a couple of inches so not ideal in a modern house which doesn't have high ceilings anyway.

Cost is based on square meterage rather than number of rooms as it can vary so much (unlike with rads where you have 1 in each room)

It's VERY unlikely that a pipe will burst once it is in the floor. We've never had one. With UFH you have no fittings in the floor either so you don't have a problem with leaky fittings either.

Thank you so much. It has timber floorboards throughout. Forgive me for being so incredibly dense, but what is it connected to/controlled by?

Ok, for timber floors you would need to have insulation laid between the joists. You would ideally then have aluminium diffuser plates (which spread the heat). The pipe is laid in channels on the plates, then the floorboards go back down on top. With timber floors the temperature needs to be higher than for concrete floors (around 60degC) as timber isn't a great heat conductor.

What you would need is a boiler - same as for a conventional system. You would then have a manifold for each floor. This has a pump pack attached which sends the warm water around the system. In each room you would have a thermostat which is wired back to a wiring centre to which the pump pack is also wired. Then each room can call for heat individually depending on what's required.

This makes the heating more efficient as you can have room which are rarely used set to a lower temperature than heavily used rooms. Bear in mind that a UFH system is designed to be on all the time (apart from summer obviously) and would be set to automatically knock back 5deg at night. This makes the system more responsive as the whole house acts like a thermal mass and you don't have the extremes of temperature that you get with conventional systems.

Personally - I'd go for UFH downstairs and have rads upstairs - mainly so I've somewhere to dry stuff when it's wet outside! Also I'd want carpets upstairs and that would restrict the heating even more (meaning it would have to be run at a higher temperature and cost more to run).

Hope this helps. Feel free to ask any more questions.

My inlaws have ufh in their kitchen and it has proved to be a problem, as they have found that the rads in other parts of the house aren't balanced properly (apparently the installers didn't suggest to install a stainless steel tank and so the pumps aren't working correctly - or something like that!) when they turn the ufh off at the mains bit, the rads work properly. It's going to cost 1k to fixm so if you are going ufh and rads, make sure that the installers check that everything will balance properly!

We have underfloor heating (most unusual in Oz) and it was set into the concrete slab when the house was built.

It is controlled by a thermostat in the same way as any heating system. With ours we also have isolation pipes- if you want to close off heating to any particular room- in an airing cupboard.

The system we have are not pipes as such- they seem to be heating coils and in the 20 years the house has existed, no problems have arisen.
The only prob we do have is that there are much warmer patches on the floor- most seem to be in doorways- so the cat lays in places where we trip over her constantly in winter.?

We're rebuilding our house at the moment and have installed UFH, run using a ground source heat pump, as part of the rebuilding of the concrete floors which had to be removed as they were very badly constructed. I won't go into the ins and outs of the construction as you are looking at different floors. We laid the UFH tubes ourselves (our builders did the rest of the floor construction) and it was very easy to do.

We aren't living in the house yet (well we are camping in there at the moment as we are living in a summer static caravan in the garden and the temp in the caravan was down to -2 deg C during the day, everything froze etc) but the lack of rads and the warm floor is most pleasing. UFH/ground source heat pump is usually run to provide a long lasting background heat so we intend to have a wood burner or two eventually.

Having slept in a very, very cold caravan for the last nine months, sleeping on a UF heated floor last night was lovely. Infact I was far too hot!

Whitty1 - do you work for the well known UFH company starting with U?

No I don't. I work for one of their competitors ? GSHPs are the bane of my life!

Ah sorry ! ? We're still in the early stages with our GSHP but impressed with it so far (although you should see the state of our garden!). I understand your frustrations though!

My biggest problem with heat pumps is that people (in general - not you) expect them to work miracles and they don't! If you want to get the 4:1 ratio out of them then the heating can only run at about 35deg. Generally not enough to even run UFH let alone rads. Obviously it depends on screed depths, building heat loss etc but even so - I can't imagine that they are always successful. One of the companies we have dealings with (Kensa) say that they tell people not to bother having one if there is mains gas in the area as it's just not as cost efficient. Although if the price of gas KEEPS going up - they may well change that stance!

Yes, totally understand (I'm an ex-chemical engineer so understand more than the average person does about heat transfer etc). Interesting to read your comments. We bought our GSHP from Kensa, they're just up the road from us. We only considered it as an option as we have had new external walls and new ground floor built to above building regs specs in terms of insulation. We wouldn't have bothered with it if we'd not done all this.

I still think they are a nice little bit of sensible and neat engineering, but then I'm quite dull like that ?

Ah well, if you've had Kensa involved I'm sure you'll be fine. They are a great company to deal with. Unlike others I could mention..... ?

That's reassuring to hear. They have been very good so far. We chose them because they are local so that if things go wrong, we can go and sit on their desks until we get it sorted. They have provided really good support too and our govt grant application went through very quickly.

They are lacking in their installation instructions though. Faced with 2 x 1.2m diameter coils of 300 metres of poly ethylene piping to be buried 1.2 metres deep, horizontally in the garden, it would have been useful to have some better hints as to how to handle them than 'first bury your coils...' ? - you should have seen the pickle we got into with the first coil. The second we managed better with!

We have under floor heating in our new house and I love it. It's great not having radiators everywhere.

The only problem I've heard of (from our neighbour) is if you have problems with varicose veins it can be uncomfortable. Not sure if this is true or not as not been affected so far!

That would most likely be caused by having it on too hot. The idea temperature for the floor is around 21-22degs. Not like at my mums where the floor was set to 30deg - made me feel incredibly sick. And my mum said it made her ankles swell. (That was electric though)

[craash!] Can you help me? Our system is an electric one, and it's under a wood floor in one room and tiles in another. The wood room never seems to get quite warm enough underfoot and the thermo has a setting on it where you put in what floor surface you have, so when it's set to wood, the max is 27degreesC which just doesn't seem to be doing the trick. Is it working properly or do I need to just over ride it and turn it up? It goes up to 35degrees and under tile we only have it on about 18degrees.

Thanks! x

I've never understood why electric ufh companies tell you to have it lower under wood. Definitely up the temp on the wood. Tiles need to be lower as they conduct heat really well. Wood has a higher thermal resistance so needs to have higher temp for the heat to get through. I would suggest upping it to the maximum temperature and see how it feels. It should feel too hot. Gradually bring down the temperature to a level that feels comfortable and see what the setting is. The maximum floor temp we work to is 29degC. Usually it works out at about 26 as a comfortable level on a wood floor. If it still isn't working properly you'll need to get it investigated. It maybe that there was no insulation under the heating mat in which case the heat is going down as well as up. Bad news!

We just installed it in an 1860's house over 4 floors. Love it! It replaced an old steam radiator system which was ugly and had scalding hot radiators & pipes.

We were doing a major renovation, and since we had the ceilings down but didn't want to rip up the floor we used a staple up system from Rehau with pex tubing and alminum plates for 3 floors. We went in from above rather than below on the tile bathrooms since we were replacing the floor anyway. We have the radiant in the ceiling rather than the floor in the bedrooms, as we did not want to pull down the ornate ceiling below. We have mostly refinished wide plank subfloors, but a couple of new wood floors.

The trade-off is your flooring material all needs to be low R-value s we hav only thin area tugs wirh mesh non-slip backing (no underlay or wall to wall carpeting). I couldn't use the cork floorng I wanted in the kitchen, and our contractor highly recommended only using quarter-sawn oak on the new floors as expansion/contracton is minimal.

Comfort wise its amazing. The thermostats are all set at 68 degrees but it feels much warmer, and its a comfortable heat. Efficiency is about 40% less gas than the old system but we know that was 30 yeard old and inefficient.

Look at Viessman for boilers and water tanks -they are expensive but realy are the dogs whatsits in effciency and controllability. We have gas fired boilers with water circulating - cheaper to run than electric.

Give me a shout if you have any specific questions based on this.

Oh and we paid about $50k (US) for a 3500 sq foot house over 4 floors with about 10 zones.

Just read Pud'sposts... I would have loved a heat pump, but couldn;t justify the cost. I agree about them being neat engineering...I used to work for a company that made heat transfer systems!

I have Warmup under our ceramics and it is brilliant. We have a moderately sized kitchen and have 1200w of elements. I have it set to do 26c in the daytime and weekends and 21c dormant. The natural temp of the floor is 18c so only 3c increase overnight, in the day etc. In the morning the (TRV controlled) rad does sometimes kick in if it has been cold in the night and pretty much never heats up during the evening. So, overall they definitely can heat the room.
Power Supply Cost - doesn't seem to be massive in anyway for our 1200w. I have a lot of power hungry kit that is on for a lot of time and our electric bill is never more then £50 in winter a month.