BTU for bathroom

[John]

Can anyone give me a quick idea on the BTU requirements for a radiator for a bathroom - approx 2metres square. insulated ceiling - 1920's walls - double glazed window.

Thanks

[John Rumm]

Not without knowing how many walls are "outside" walls, and what rooms adjoin it to the sides and above and below.

[John]

================================================================/

Two outside walls - two internal stud walls. Bedroom and landing.

Thanks

[Mike Hibbert]

have a look on the B&Q website - they have a BTU calc on there.

[John]

Done it - thanks

[Nick H]

Using a "mears" calculator, a 6'6" x 6'6" bathroom, 7'6" ceilin hieght, 2 outside (solid 9")walls, on the first floor, design temp o

72 degrees, gives a BTU requirement of 3200

-- Nick H

[The Natural Philosopher]

About 500W.

[Andrew Gabriel]

I calculated 875W for a bathroom 1.2m x 2.4m, 9" brick walls (two external), insulated ceiling, small double glazed window, using the Myson calculator. In practice, the Myson calculator seems to have over estimated throughout the whole house (it was a beta version), although that has meant I can run the boiler at only 45C once house has warmed up, making the condensing boiler very efficient, so I'm not complaining.

[Andy Hall]

I'm sure Myson aren't either ;-)

[Andrew Gabriel]

I didn't use their radiators. Most of mine are Ultraheat ones. I needed a few low height triple panel ones to go under some low windows, and I liked the Ultraheat 6 range with bottom connections. There's one Stelrad too, where appearance didn't matter so much.

[John Rumm]

That reminds me... I did a set of calcs for our place prior to doing the loft conversion etc. The existing bathroom came out thus:

Surface Air Area Tdelta u-val Loss Change Vol

Land wall 4.83 6 1.2 35 0.50 10 office wall 4.6 4 1.2 22 side wall 4.6 25 2.2 253 rear wall 2.83 25 2.2 156 window 2 25 2.9 145 floor 4.2 4 1.5 25 ceiling 4.2 4 1.9 32 Total 668 43 711

So 711W for a simlar sized room - two 10" solid exterior walls, two internal stud walls, kitchen under, loft over.