Have been working out some sizes for my house using different calculators /formulae.

There is a vast range in the results which bothers me.

Example

Lounge - no double glazing - one outside wall
size L 5.36 W 4.7 H 2.4 mtrs

Results in BTU's are:

1) 9432
2) 11016
3) 11185
4) 8400 - 10075
5) 8948

Can someone give me a clue?

Thanks

No idea on rad sizes matey, but these people are very cheap for systems and rads
http://www.mrcentralheating.com/

Good luck
Jason

[Edited on 19/11/06 by Deckman001]

nip in to B&Q and grab one of there radiator booklets, there free and theres a guide in the back to the size of rad u need in comparison to the room

John

thats not much variation considering how unexact a science it is, picking a radiator. Remember, you can always turn it down! So id just pick the biggest, and make it a double convector to keep the width down.

Although I'm not a domestic plumber, for commercial premises we work out rads at 5Btu / cubic feet. New builds obviously less, depending on the u value of the building.

I would always suggest going slightly over as the rads are tested in ideal conditions ie top and bottom connection not both bottom. And as said, you can always turn them down.

I agree with Joel. Those double rads are excellent.

Where did you get the formulae? You should be taking into account wall construction, floor and ceiling/ roof construction, windows, doors, orientation etc etc. Try plumb center website, dont worry too much about variance, look at actual rad size to satisfy your btu's, go slightly on the higher side as already posted. Good luck mate!
Tim