Underfloor heating - how good is it?

EvilMonkey

I'm in the process of planning out 2 bathroom refurbs. Both will end up with stone flooring, so I thought underfloor heating might be the way to go.

How good is it as I'm getting mixed reports from the local people, some say it's only good enough to take the chill of the stones, others say you could use it as a source of heat (IE no radiator). I did see one site which indicated it was dependent on the wattage of the heating, but gave no indication of what a "good" wattage would be?

1 of the rooms I'm converting has no external walls (and no windows) and is on the ground floor, do your reckon I might be able to get away with no towel rack?

Any thoughts?

E.M.

EliteHeat

Underfloor heating is extremely good for predicatable heating paterns - 'cos it is really slow to react.

Electric is good, gas is better.

Do not install it in major population areas if you want instant heat.

Hope that helps. :cool:

benood

I think it depends a lot on the installer - we had it in the conservatory in our previous house and it was dreadful - expensive and imperceptible, my parents have it in a bathroom where it's great. Both are electric.

Fulham_Mark

As i understand it there are two types of underfloor heating.

One is used with a condensing boiler (i think) and uses partially heated water which circulates in a mesh of pipes. The other is a kit type that is a mat of an electric element that you put down under tiles.

I'm no expert but I imagine these "kits" are pretty awful, expensive to run and more for amateur DIYers like me who want this heating for the pose-factor!

The other type is much more interesting. Physics (newton's third law i think) would lead you to think that heating a room with a small very hot think is not as effectient as heating it with a bigger but less hot thing.

If you combined an underground bore-hole with underfloor heating you would nearly get free heating and cheaper hot water for life.

I believe in scandinavian countries this is the standard way to heat homes now. It's also the norm in Korea but i don't know if the the bore-holes are involved.

iamcornholio

Underfloor is a very good system, but you must be aware of its differencies to typical systems like radiators.

You get no perceptible points of heat emision, and no radiant heat like from radiators or fires. So you can't feel the room heating up. This is the main reason why people think underfloor is not as good as normal central heating radiators - basically the room can be just as warm, but it 'feels different'.

Also the heating takes a longer time to heat up the floor and give off the heat, so it is not like radiators clicking on and off and heating the room up in half an hour. So although you have to set the underfloor to come on sometime before you need to use the room, it is actually more efficient once the room has heated up.

You also get fewer or no convection currents so comfort is greater. Radiators move air around as the heat rises and cooler air is drawn towards them - causing draughts in the room. You don't get this with underfloor as the whole room is heated, and not just areas of it.

The important thing is to make sure the system is correctly sized for the room. Floor area, area of any doors and windows, external walls, insulation and heatloss, all make a difference. So the underfloor has to be able to heat the room and allow for any heatloss through the walls. If it is not correctly sized, then it will never heat the room up enough during the coldest times of the year.

Electic mats may be less efficient and not as good as a wet underfloor system. You need to calculate the rooms heat requirement ( in watts or BTU's) and then see if the system can deliver this. If a wet system, check if the boiler has the extra capacity

missile

I have (wet) underfloor heating in my lounge and it works rather well in conjunction with a room thermostat. Obviously stone flooring will be cold, underfloor heating may make it feel a little but not much warmer. In a bathroom you may like the convenience of having a radiator as a convenient way to dry towels.

EvilMonkey

iamcornholio wrote: »

Electic mats may be less efficient and not as good as a wet underfloor system. You need to calculate the rooms heat requirement ( in watts or BTU's) and then see if the system can deliver this. If a wet system, check if the boiler has the extra capacity

I'd planned to use an electric system (mat or wire), are they hideously inefficient?

Also how would I go about calculating a rooms heat requirement?

Thanks for all the replies, not sure now whether this is a worthwhile investment or just the latest fad...

E.M.

iamcornholio

For calculating heating requirements, look at www.myson.co.uk , or just google for " heatloss calculator ".

I've no connection with www.allbriteuk.co.uk , who sell electric underfloor systems, but I have debated with the owner on another forum in the past, and he sounds genuinly knowledgeable about the product, and not just after a sale. In anycase, the site has lots of useful info

economiser

Electric heating in any form is expensive. I would not recommend electric heating unless you rooms are very well insulated or very small. Probably OK for a bathroom.