Correct size of radiator for size of room

[gordonv101]

Hi

A bit of advice please regarding the size of a radiator for my lounge.
The room is approximately 18' x 12' and it has three outside walls. There is a double glazed sliding patio door on one wall and a fairly large double glazed window on another wall.
It currently has a 600 x 1450 double rad with double convector and it does not get the room sufficiently warm in cold weather. We have to put on the coal effect gas fire to get the room warm enough.
MY QUESTION IS.... If I replace the radiator with a larger 600 x 1800 double with double convector will it make much, if any difference. That is the largest size rad that will fit.
All info greatly appreciated and many thanks in advance.

 

[SimonG]

How high is the ceiling and do you have a wall where you could position an additional radiator rather than just a bigger one. Sometimes it can be about position rather than size.

 

[Atouchofgas]

It will not improve the heat out by much, if your walls can cope you could look at stelrad k3 600x 1600/ 1800 which will give you more than k2 600 x 1800

 

[gordonv101]

Hi
Height of the room is 7' 9" or 2360 m. The only other place to put another rad would be the opposite wall to where the rad is now which would be under the window but as the curtains are full length down to the floor it is not an option I wanted to consider.

 

[Gray0689]

You will need approx 4kw at minimum
So look at a radiator sizing chart for rad sizing to suit

 

[GrahamM]

As mentioned, look at a radiator sizing chart for more accurate estimate, but as a rough estimate you will be looking for at least another 600x1800 to give sufficient heat.
The difference fitting a slightly bigger rad would be negligible.

 

[erpkid]

I would look at the possibility some form of additional insulation in the room if the budget and appetite for disruption allows.

 

[turnpin]

Firstly check if your system is balanced correctly possibly look into verticle radiator had to fit one of these on a job due to lack of space sorted their problem hope you sort yours regards turnpin:8:

 

[lame plumber]

is there anything on top of your lounge ie more rooms or is it a roof/flat roof, if so you need more insulation not bigger rads.

 

[ggman]

I had the same problem but I found the spaces to put 3 vertical rad at the side of the windows and it works really well.
Another option that I was considering was to replace the inefficient gas fire with the Smiths Hydroflame Classic Inset Flame Effect Hydronic Fan Convector Heater,expensive but efficient 2Kw on fan boost it will warm up quickly.

 

[gordonv101]

Hi
It is a bungalow so there is just roof space above which is insulated although I dont know what thickness of insulation. I suppose it is something I need to check. Thanks

 

[michael c]

hi gordon, i know you have mentioned you wouldnt like a rad under the window due to your curtains but even a small radiator would help to a degree. Your windows and patio doors although double glazed are designed to allow a small amount of airflow around the frames, this is to facilitate air change/circulation in the room. From what you have said the rad is away from windows and patio doors? Therefore the air coming in is hitting the warm air in the room cooling it. Basically by having radiators near windows etc the cold air is warmed as it enters the room instead of cooling th the air already there.

 

[Best]

I had a similar sized room (approx 18ft 8" x 13ft) to calculate a few months ago for a bungalow.
Eventually opted for 2 rads (replacing just one old rad that was at one end of the room). Has to be better to spread the heat on largish rooms.
I used a 500 x 1600 double & a 500 x 900 double approx.
A little extra output is a good thing for living rooms when temperatures outside go well into minus numbers, as long as you have TRVs fitted.