What Does The kW Rating Of A Radiator Tell you?

[charliegolf]

I've seen rads rated at 3kW. If I fit one on my CH system, will it heat a room as well as a 3kW electric heater?

I have a conservatory, and in he deal (not free!) was 1.6kW of electric u/f heating. If I stick a 3kW rad in there, will it be twice as toasty in there; and much cheaper? Probably not, but I thought I would ask experts. Ta.

CG

 

[big-all]

1 kw off electric heat costs around 3 times as much as a 1kw on gas
are you sure its 3kw thats a huge size??

 

[ScottishGasMan]

3kw is large for a radiator, but maybe its a large radiator?

3kw will be its maximum heat output given a set room temperature, a set water flow rate supplied at a set temperature to the radiator with the correct temperature difference between the flow and return to the radiator.

All in all alot of variables.

3kw realistically will be the maximum the radiator "could" give out. But in short yes, a 3kw will have you a lot warmer than a 1.5kw rad, as long as your pipes are big enough to feed it, conservatory's/garage conversions are notorious for someone piping in some thin microbore into a massive radiator and just not being set up right.

A conseravtory generally has a massive heat loss so if you are to heat it in the winter then you do need quite a decent output of rad or underfloor,

 

[charliegolf]

Thanks for that. I'm under no illusions about heating a conservatory in the winter, but my wife likes it, especially when there's a houseful. The discussion came up because I was having a routine service on the boiler, and I asked if a rad could be fitted without pulling the house about too much, and sure enough it can. My questions were to see if it's worth doing- we would certainly be using it a lot NOW, even when the evening temps round here are getting low. Bright winter daytimes would be my wife's heaven too, so I don't mind exploring it.

On piping, mine is all 10mm. Would going from the manifold in 15mm improve efficiency? Ta.

CG

 

[ScottishGasMan]

For a 3kw rad, I would go for 15mm. 10mm can supply 3kw but only in correct circumstances as outlined above.

15mm will work for def, just make sure you are taking it from a manifold/primary pipe and not stealing the heat/water from a smaller feed to other rads.

Def worth doing IMHO, it will be noticably warmer. Obviously bills will increase at same time, but gas is cheaper than electricity so you shouldnt notice a massive difference, make sure to fit a TRV on the radiator so when the room is not in use in the cold weather so it doesnt waste loads on it but will still open if it gets "too" cold.

Ive fitted a radiator in my conservatory, wouldnt be without it, but its a pretty small conservatory, probably less than 2m x 2m

 

[JBPHS]

Remember that radiators were and still are if I'm not mistaken sized so that they are installed as top and bottom opposite ends (TBOE). Where the flow enters a top connection on the radiator and the return is at the bottom on the opposite end.

Even though you can do a thorough calculation to give a good estimate of the heat loss of your conservatory through the building fabric and ventilation, approximately 30% is added to the estimation for the radiator sizing.

James.

 

[St0rmer66]

Most installers will ignore this but... Technically a new radiator (existing ok) in a conservatory should be on a separate zone valve with its own thermostat. Often ignored and never checked up on but to be correct it's more hassle than you originally think.