Plumbing Question

My house gets very cold in winter - should i change my radiators?

My house gets cold in winter although I have a combi boiler powered central heating system (approx. 13 years old), double glazing (15 years old) and have cavity wall and loft insulation.
When the heating has been on for over an hour I can generally only feel the heat around the immediate area of the radiator and not the rest of the room. The radiators are generally very hot however. All the radiators are singles and vary in length and there are six in total (1 living room, 1 hall, 1 dining room and 1 in each of 3 bedrooms).

So I have a couple of questions:

Could it be that the radiators were not sized up sufficinently to heat the rooms?
Should the radiators be replaced to those with a higher BTU?
Should any replacement radiators be double sized or can singles (which would look better in my house) achieve as high a BTU as a double?
If new radiators with a higher BTU were installed how do I know my boiler would be able to cope?
How much would this be likely to cost approximately for supply and fit of new radiators (assuming this is a recommended course of action)?
Any other advice?

Thank you.

3 Answers

Best Answer

Before you start looking at increasing sizes of radiator you need to check the BTU of KW of your Combi Boiler. Then divide this by the number of Radiators you currently have (this will give you a rough idea what size Radiators you can fit).

Once you have done that, if you can try an work out what the current BTU's or KW of the Radiators are and this will tell you how much more KW you have to add larger Radiators.

It does sound like from what you have said is that the Radiators are not powrrful enough for the job required. I think the Boiler is big emough for current Radiators if they all get very Hot.

Now take measurements of your rooms, showing windows, outside walls, etc. and take these to your local plumbing merchants and get them to tell you what the correct size of the Radiators should be for each room and the total BTI's or KW. Now check if your Boiler is Large enough to supply that total.

If not then new Boiler and Radiators or live with waht you got. But if big enough then you can add new Radiators.

Approximate rule of thumb for costs is;

Approx £100.00 per Radiator
Approx £18.00 per Set of new Valves
Approx £40.00 per Radiator to be fitd
Approx £7.00 per Radiator Materials for Adjusting Pipe Work

Pipe Dreams Plumbing Services

Answered 9th Sep 2011

Pipe Dreams Plumbing Services

Member since 9 Sep 2009

The best way to check that your radiators are suitable is to find a BTU calcualtor online. You will need to size up the rooms, determine areas of windows, and provide information such as insulation, rooms above, floor types. Once this information is in you will then be given a BTU rating for that room.

Next, you will need to determine the BTU of the radiators in the room, this can be done by measuring the height and width of the radiator and then finding a similiar one online. They will show you what BTU's they are, if they are single panel make sure you are looking at singles and not doubles.

You will now know if the radiators are suitable enough for the room size. If not then larger radiators will need to be installed, one piece of advice is to always get a larger BTU rated radiator than is needed, as this will then allow you to at least turn the radiator down if the room gets to hot, better to have more than less.

Once you have done this for the whole house, you can add up all the BTU's of the radiators in the house, with this total figure you will then need to convert it into Kilowatts (KW). Your boiler will have a KW output and quite possibly a BTU output, check the manual or model number. A Worcester 24i for example gives an output of 24KW's. If your total KW's for all your radiators are less than that of the boiler happy days, if not then you may need to upgrade your boiler.

Cost wise, is a little harder to say. You'll find approximate costs of radiators online, if you don't have Thermostatic Radiator valves (TRV's) then you'll have to allow extra for these (£10-£20 each). If your changing radiators then 90% of the time the pipework will need to be adjusted, this takes time and of cause costs in labour. Realistically a plumber should comfortably change 4 or 5 radiators in a day.

Hope this (a) makes sense and (b) helps

Answered 10th Sep 2011

Pure Building and Plumbing

Member since 31 May 2010

you have hit on several reasons for your problem i would size every room and see if rads are correct size your combi is 13 yrs old and if you havent had to change many parts on it you have had a good innings out of it most boilers nowdays manufactures state 10 yrs shelf life you could do with a flush on your pipework and rads and inhibitor added thermostatic rad valves on every rad also helps as you can control temp room by room also pipesize to rads 15mm comming of a good run of 22mm circs is the only way all these remedys cost money and i would be more inclined to put this money towards a a new "A"rated condensing boiler with new properly sized rads which will put out more heat than a 15 yr old rad that has been painted a few times if you have the money i would be recomend you be proactive with a new heating system rather than reactive as its sods law it will be the coldest day of the year when it does pack in its not the best news i know best part of £2000-£2500 on an average 3 bed house ,but this is your best option but you will always get cowboys who will happily let you through money at it hope this has been helpfull .on the bright side the price of scrap is right up regards damian regards damian jwc property services

Answered 10th Sep 2011

JWC Property Services

Member since 25 May 2011

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