Experience of underfloor heating?

[Zech]

I'm not sure whether this belongs here or in 'energy' - I hope this is OK.

We're looking to replace our (broken) LPG central heating with something powered by a (salvaged) wood burning stove with back boiler (we did see this working before we scrounged it) and (possibly homemade) solar panels. I like the idea of underfloor heating, but my husband isn't convinced, and neither of us has any experience of it.

We have suspended floorboards throughout with excellent access underneath, and we understand that installing UFH that way would involve drilling a lot of holes through joists. We'd like to avoid lifting all the boards, and don't have much headroom for raising the floor level.

Husband's concerns are:

Is UFH unsuitable for use with a wooden floor (either inefficient or damaging to the floor)?

Is UFH very slow to warm up a room from cold, e.g. if we came back from a week away in winter, would it be the next day before we could get warm again?

If not slow, is UFH very hot on the feet?

We have many other questions, but I'll save those for now. If anyone has experience of UFH with wooden floors and could answer these questions, that would be very helpful.

Thanks

[oldjerry]

Rachel,I'm not sure what you mean by 'underfloor'.Firsly,I'm not a plumber,but I have fitted a few CH systems over the years,and modified/converted others.Years ago you used to get underfloor blown air heaters,but I'm sure you arent refering to them.D'you mean the pipes are undr the floor and the rads are on the wall?
You might be able to utilize at least part of your knackered LPG system (thats what we did here) while converting to your wood burner.
What sort of wood burner is it? You'd struggle to heat more than 2 or 3 rooms with most WBs with a back boiler (thats why people love Rayburns).
For me,sad,old,biased etc,if was looking to heat a house of say min 4or5 rooms I'd look round for a SH Rayburn (oil are cheap,then convert back to solid fuel with bits bought on line) run that on wood with a few buckets of coal to keep it in overnight,or when you go fishing,and if you want to stick water heating panels on your roof for the summer,or a nice cosy looking WB in the sitting room to impress your guests(they're cheap SH too),then alls well and you arent going to be spending shed loads to keep warm. ..Oh , and isn't LPG central heating crap ? betcha glad it broke! Best Wishes.

[Green Aura]

Can't answer Zech questions but I can OJs

Underfloor heating is made up of zig-zagged pipes, laid on some sort of insulation, throughout the ground floor - no radiators or anything above floor level.

As far as I know it's OK with wooden floors but if you look at the different types they recommend one thing for wood and another for tile so you need to be careful what you get. I don't think you can put it under an already laid flooring no matter how good the access, although I might be wrong there.

I'm also not sure how it would be efficient running it from a wood burner, my understanding of underfloor heating is that it's little and often - so it's on more or less constantly but at a much lower temperature than radiators would need to be to warm to the same degree. They run well off something that can also work constantly like a ground or air source heat pump (or leccy or gas boilers).

Oh, I did manage to answer a couple of them

[wulf]

I love standing on bare floor boards above where the central heating pipes run! That's not quite "underfloor heating" but does give a couple of spots that are good to stand on in the winter!

Wulf

[grahamhobbs]

Once you get used to the warm feet syndrome, underfloor heating is usually concidered more comfortable than radiators. It can be used under timber flooring and takes a little longer than radiators to heat a room but not excessively so.

The problem though is it would not be practical to install without lifting the floorboards. The pipes have to be installed with insulation under them to prevent heat being wasted downwards (remember the under floor space is ususally ventilated to the outside). Also with a timber floor the heat of the pipes needs to be spread over the entire floor, this is done usually by either burying the pipes in screed or by using metal spreader plates (into which the pipes sit). In both cases the timber floorboards should sit in direct contact with the screed or metal plates. All this is only practical if you lift the floorboards.

[Zech]

Thansk for the answers. We've done a bit of research into whether it would be possible to install UFH without lifting the floorboards. There's a Thermoboard system advertised as, "Can be installed from above and below."
http://thermoboard.wavin.com/master/mas ... ervice_sub

We also had a quote from a plumber who'd be willing to install from below - as I mentioned, this involves a lot of drilling. It's obviously not easy - the quote was high - but it is possible.

My question was really about what this sort of system is like to live with, but if no-one here has such a system, I guess I'll have to ask around elsewhere.

Comments are appreciated, though.

Maggie - To make UFH work with a woodburner, we'd have an accumulator tank between the two, so the once-a-day use of the woodburner heats up the water in the tank, which then provides a relatively constant source of hot/warm water for the UFH.

OJ - the woodburner we have was heating a hotel bar in its old life. I reckon the area of that bar is about the same as the area of our house, and the ceilings there are much higher too, so I'm reasonably confident the woodburner will be up to the job. One plumber who looked at it was mostly worried that it would provide too much heat, not too little. Our LPG central heating was certainly crap! That same plumber looked at the pipework in horror and told us it was no where near adequate to get enough hot water to the end of the house. That would explain why that end of the house was always cold, then! A different plumber asked if we'd be wanting to keep the pipework - I was less impressed with him. I'm more likely to strip out the pipes to make a solar panels out of them

Wulf - the joy of warm floorboards over the pipes is my main reason for wanting UFH!

Graham - when I said there's excellent access underneath our floorboards, I should probably have been more specific. Our house is effectively an upstairs bungalow. Downstairs we have garage, storeroom and workshop. Between the two we have floorboards only - you can see straight through the gaps from upstairs to downstairs. It's not going to be difficult to insulate under the heating pipes after they've been installed. At the moment we're wasting plenty of heat downwards - we've been holding off on the insulation until we get the new heating in place. As for ventilation, that's also lacking, and something we need to deal with.

Thanks, all

[fruitcake]

We have underfloor heating, but set in concrete with wood or tiles over the top - love it. It's a really efficient way of heating the house - partly cos the concrete acts as a heat sink. It takes a wee while to get used to if you like the way radiaters come on and off, cos it's a more constant, mellow warmth. Am not too sure how it would work between timber floors.

[george]

We have underfloor heating too. In fact, pretty much everyone in Korea has it. I like it as it gives a nice warmth and the floor is warm too. We have vinyl (wood effect) floors. Here in Korea most people sit and sleep on the floor so they sit on the warm area too. It used to be run from fires heating water but these days it runs on gas. We have a controller which allows us to set how often it comes on and the water temperature. Our previous apartment was warm so we had it on every 4 hours at a low temp (40C). It also has a setting for when you are away to keep the minimum temperature to about 16C. This helps prevent the pipes freezing which is needed here as temps often get down to about -15C at night. It is pretty cold here but the underfloor heating is our only heating source and we have no problem staying cozy and warm.

A few minor problems are that it does take a while to warm up so if you want a short burst of heat (such as after a shower) a direct heat source (electric heater) might be a good addition. The other thing is that it is quite drying so many people here also run a humidifier during the winter to keep moisture in the air.

I like it and like the way it feels and would happily have it as my heat source again. If you have any other specific questions, please ask.

[grahamhobbs]

Zech, the system you have found looks ideal, with the diffuser being integral with the insulation. I don't think that there needs to be that many holes drilled in the joists, although installation from underneath could be very fiddly, you've got to get the pipes into the channels in the insulation and then push up under the floorboards and the piping has a mind of it's own. However the installation of the pipes and insulation is not a skilled job, you could save money by doing that yourself and just have the plumber connect up the manifold and controls.

[Zech]

Thanks very much for the replies - husband is now happy to go ahead with UFH

As we struggle to dry out our old, damp, Welsh cottage, I quite like the idea that we might need a humidifier

[Green Aura]

As we struggle to dry out our old, damp, Welsh cottage, I quite like the idea that we might need a humidifier

I think you might need a dehumidifier, zech! Make sure you get the right thing of you might turn your cottage into a swimming pool

[Milims]

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