underfloor heating, suitable to heat a room or will i need radiators aswell!!

andrew-b

Having been destructive to your plan i'll be a bit more constructive for a change!



Changed the position of the door slightly but you could probably get away without (sort of inspired by all the diagonal walls in our house! I think it adds "character"). Thought as you might as well show off your induction hob in the middle (Paint isn't the easiest of tools to draw diagonal parallel lines with - much prefer Google sketchup!)! My plan makes the rerouted waste pipes in completely the wrong place though. But the main point is i've seperated the room into functional parts with the creation of space.

Anyway might gives you a better idea of what i mean! Kitchen design isn't rocket science. Oh and my plan your free to have!!

Andy

brig001

To your original question: if the extension meets building regs, you should be fine with underfloor heating. Back of an envelope calculation says roughly 30m2, 100W/m2 with tiles = 3000W, down to 70W/m2 with laminate (use thin underlay) or carpet = 2000W. As a guide, our entire house (100m2) only needs 3000W to get 20 deg C inside when it is 0 deg C outside and it doesn't meet modern building regs.

If you are in during the day, I would use pipes in screed, if not, fit a timber floor. We did pipes in screed and it takes a while to get going, but then it is brill.

HTH,
Bri.

stolt

thanks for all the replies, didnt get a notification so wasnt aware anyone else had replied lol!! andrew-b, i've forwarded your picture onto the missus and see what she says.
brig001 - yep house fully complies with building regs, and apparently is actualyl a better save rof heat than the house!

Had a plumber round at the weekend just to price up laying some pipes into the extension floor before the floor goes in, he wants £200.00 to lay them only! priced on a days work but did say if he can get it done sooner then it wont charge as much.

stolt

heres a couple of pics knocked up with the google sketch, starting to get the hang of it so might have a better go lunch
time.

MontyCarl

Ok, this very nice of floor heating and if you any help of floor heating please conceder warmyourfloor..

stolt

just want to ressurect this thread again, building inspector mentions if it was him he would put two rads in and i'm trying to work out the BTU's needed for the space i have. I was thinking of two 4000 BTU's rads which would cover a room of 20ft by 20ft roughly. plus i would have the underfloor heating....

cooked my brain so im struggling to work the maths out....help


just tried lots of online calculators with both feet and meters and well they are all showing different results.

andrew-b

stolt wrote: »

just tried lots of online calculators with both feet and meters and well they are all showing different results.

indeed they do..because they are all based on different assumptions about the constructions materials used and make assumptions on temperature you want and temperature differences between adjacent rooms. There's so many variables you can't possibly expect an online calculator to get it right. Many seemed on the high side to me so probably aimed to make you buy a radiator bigger than you need!

There's a calculator produced by stelrad which saves some paper..downloadable software but i forget where i got now and it's on my other pc..think canucklehead posted the link somewhere.

Anyway if your rewind to my post in post #5 i gave a link to how to work it all out and if you follow it there are links to tables of figures of U-values.

It doesn't matter greatly if the radiators give a bigger output than you need (other than expense of the rads) as you can just whack a TRV on to control them. You don't want them too small an output. As you are having UFH as well don't forget to subtract the output for that before you work out the rads required.

Also you'll find the outputs of rads are often quoted as being based on a temperature difference different to what your own calculations are so sometimes you have to make adjustments to the figures to match your heat loss calculations. Think there is guidance in that article. Recall doing these calculations in A-level physics at school a long time ago. I usually stick to watts/celcius/metres rather than BTUs/ft/fahrenheit as it makes the numbers a bit more intelligible to me - doesn't really matter which units you use so long as you stick to the same throughout.

Andy

stolt

Thanks andy, it was all getting a bit too much for me last night (too late) was going to try again in my lunch hour. I will need to speak to the extension people to find the output of the underfloor heating. The trouble is i may not have the underfloor heating on all the time, the company that are fitting it said that it would be fine to just have that and no rads but i think sometimes it will be nice or if i just need to take the chill out of the room i could put the rads on for an hour or so. Never had underfloor heating so not sure what to expect. will try lunchtime to work it out again when i did it in feet the btu's came out to about 12000 and in meters it was near on 15000!!! (i didnt know what i did wrong the rads i was going to install were only 5000 BTU each and I only wanted two.

Idiophreak

Just my two cents worth - I've just moved in to a new build with wet underfloor heating, never having had it before in my life. We spent a while testing it when we moved in, thought our experiences might be of value to you:

The thing that took me a while to get my head around is that the system works more on "constant heat", than on heat-up, cool-down - completely different to normal radiators. The underfloor heating can take several hours to get up to temperature, as it has the whole floor to heat, rather than the small bit of metal heated up with a radiator.

This being the case, to get the most out of the system, you can't think "It's chilly today...I'll pop it on for an hour...", you have to think of it more as "i'll have it on from 1-7 so the house is warm in the morning, then from 12-6 so it's warm when I get home from work" - it's all on thermostats etc, so it's not going to make the place too hot or use more energy than it needs to. Obviously we've not been through a winter yet, so can't really comment on the costs of this, but other people have assured us that the cost isn't substantially more than "normal" central heating - and our tests (making the room 30' for a couple of weeks...) didn't seem to sky-rocket our bills.

Final thought: Personally, I hate radiators. They take up wall space, look ugly and wilt the christmas tree - so I think by installing radiators you'd somewhat defeat the point of the thing...If you really want something to take the chill out, on a really cold morning, why not get a little fireplace installed that you could fire up, just to give a little radiant warmth...

stolt

thanks for the reply Idiophreak, ours will be the electric system so i dont know how much of a difference that will make plus the room is large. I agree about the rads thats why we were going to buy a couple of the desinger bisque radiators that are very nice looking. I just dont want to mess this room up, its the heart of the house and I would hate to have aharsh winter and everyone decides that they would rather be somewhere else other than that room.