Advice on new radiator??

[gg]

Hi

I have a largish house and the radiators I have just dont seem to cope with a couple of the larger rooms...

I have a new boiler (condesning 28i Worcester) so I think its time to 'upgrade' a radiator or 2

The main room is 16ft x 15ft (high ceilings) and currently has one radiator (I dont know the output) - from cold (around 16 degrees) - it takes approx 4 yo 4.5 hours to reach 21/22 degrees (the point when the room thermo cuts it)

Another room (slightly different problem) is a 12x13ft bedroom, NE facing, and 3 x external walls. This bedrrom suffers from condesation in the cold days (in the corners) - as the radiator is offset on the opposite wall to window...and the room never seems to get above 16/17 degrees no matter how long you heat it!! (especailly the corners!)

So, can anyone advise on (for the main room) - on what type of radiator to buy. I notice on Screwfix they have a range of rads that are higher price the higher BTU...can I go TOO high, or not good for the Boiler?? I wouldnt need a TRV and the main room is the room with the thermo

Current rad is approx 1300 x 660 mm and is approx 10 years old (still gets piping hot though!)

Ive seen this one a 600 x 1800 (longer would heat more evenly?) - for about =A380

this be suitable?

For the bedroom, is this just a case of a larger / high output rad also?? I cant get the rad under the window and I just would like the room to get warmer!

I would like to buy the rads, then get a plumber/handyman to fit the, (presume its case of rehanging and altering/extensing the pipework?)

Any advice on what to buy what not to buy would be most appreciated. I suppose I could just ask a plumber, but Im actually interested in the differences of rads...

You DO learn so much here!

I work in IT, so quite far from the skills of DIY....but Im happy to try to answer any questions!

Many many thanks again

[Stuart]

Have a look at the radiator calculators here .

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[Ed Sirett]

Ideally you should try to get some estimate of the heat requirements by running the numbers through a Heatloss calculator. (Doubtless there is one on line).

If the main room were to warm up more quickly and thus cut the thermostat would this be a problem for heating the rest of the house?

Are the radiators in the problems rooms fully hot?

Essentially you will need to add extra radiators and/or replace the existing with higher output units.

If you exceed the capacity of the boiler all that happens is that all the radiators cool down a bit and the boilers run full on continously when the heatign is on. Hopefully the 28kW boiler will be sufficient. If it isn't it will almost certainly make more sense to reduce the heat losses and excess draughts than to increase the output.

With a condensing boiler there is no such thing as too many radiators. The TRVs will simply cut the flow to balance the heating needs.

[gg]

Not really, at the moment, the rest of the house seems to heat up a lot quicker than the main room (the main room unfortunately being a semi attached to an empty property and with 3 external walls)

Yes, very hot, slightly not as hot at bottom but generally very hot to touch

Yes, seem to be the case! - The cals online I tried suggest 7000 BTU!

We dont have draughts (well no big ones!) - and have new loft insualtion. Problem is our house is old has solid brick walls (no cavity to fill) - the outside walls are quite cold and noticebly colder in the corners where the radiator currently is 'offset' and so doesnt heat that well. We have floor/ceiling curtains that do a good job of blocking cold air from UPVC window

Ok, many thanks

Is it best just to buy the radiator that has the highest BTU rating (for the size that fits the room!)