#### diybristol

Has anyone found a really good guide to BTU on the net?, I am trying to work out how many more Radiators I can add to my system, I want another 3 really.

Also does anyone know if you can get special ones that use less BTU but pump out more heat?

I understand what a single rad is and a double convector but what is a P+

???

[code:1]special ones that use less BTU but pump out more heat[/code:1]

Hmmm, like having your cake and eating it.

BTU is a unit of energy, or heat if you like. Eg if you have a 50,000 Btu/hr boiler and you want to get all the heat out of it, you need rads capable of losing that amount of energy between them, into the house.
The BTU rating of a rad is the emount of energy it can shift from the water in it to the room. Does that make sense?

WHat you need to do is work out how many Btu's/hr your new rooms need, add to what your existing rads are rated at, and compare with your boiler. Not a simple task first time when you aren't familiar.

To "visualise" how much energy you need it might help to think of electric heaters, which are usually 1 or 2 Kilowatts. 1 kW = 3412 Btu/hr.

A P+ rad is usually one with 2 panels, but with convector fins on only one of the 2. It makes a thinner rad

Also does anyone know if you can get special ones that use less BTU but pump out more heat?
The Btu/hr rating is a measure of the rate at which the radiator gives out heat. You can't get something for nothing......unless you're Corgi I suppose.

I do actually have a 50,000 BTU boiler only new last year then I did an extension and want to add 3 new rads to 3 rooms.

Not going to put rad in kitchen as no where to go, thinking of a plinth heater???? any good???

A P+ is what dodgy plumbers do ,and get caught on camera A plinth heater is a good but expensive idea.You need to know the actual heat requirements of the whole house...the heating may have been installed before the cavity walls were insulated..and/or double glasing fitted. Therefore your existing rads may be too big...if they`re fitted with thermo valves, they will modulate down as room reaches required temp. The worst case scenario is that you will end up with a house that never quite reaches it`s design temp.Also the hot water. Due to too many rads. You could go to a plumbers merchant and buy a Mears Calculator, then work out the heat requirements...it`ll cost about the same as a callout from a plumber Use it, learn. and then flog it on eBay to a DIY er The output of rads is printed in the manufacturers literature, or trade guides from the merchants.. if you can identify the manufacturer you can get an exact result for your existing ones.

There's a heat loss (radiator) calculator on the Barlo site.

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