Adequate radiator for living room?

Discussion in 'Plumbers' Talk' started by Possom, Nov 21, 2020.

  1. Possom

    Possom Member

    What temperature would you want a radiator to allow a living room to be able to get up to when the rad and boiler is set to max?

    That is, in order to allow for exceptionally cold evenings/nights.

    For example, I set the boiler to max (stated 85.5 degrees on boiler for heating system) and turned a vertical radiator up full, was able to a room temperature of 27 degrees when there an outside temperature of 12 degrees.

    The room temperature before heating was turned on was 15 degrees.

    Do you think this radiator is providing enough heat for the room to allow for exceptionally cold temperatures (e.g. beast from the east)?

    It didn't get up to this 27 degrees quickly though as it's a column rad, possibly took a couple of hours or more. It reasonably quickly got up to 22 degrees in the room though.

  2. nigel willson

    nigel willson Screwfix Select

    Theree Ed as the online calculators that you can use . You need to find the total heat loss of that room. Rad is then sized up to make up the losses
    Jord86 likes this.
  3. Jord86

    Jord86 Screwfix Select

    Look up BTU calculators online.
    Muzungu likes this.
  4. Wayners

    Wayners Screwfix Select

    Seems everywhere I go these days I see large k22 radiators vs k21 which I feel are better. Recently was working in a lounge and they had 2 large k22 radiators recently fitted and apart from this lack of space to fit furniture and with all the wall space covered, and the thickness of the radiators I have to ask why. As for temperature grab hold tight while on and if you can hold for 4 seconds they ain't hot enough.

    For size use the guides online and personality I'd buy the next size down as I think the size quoted is generous. Most ignore anyway and buy bigger it seems. Think plumbers don't want complaints so go bigger. Crazy
  5. Jord86

    Jord86 Screwfix Select

    Nothing to do with the OP but it amazes me the amount of people who complain about the cost of the heating bills yet never consider putting a dressing gown, jumper or blanket on now and again.
    sparky steve likes this.
  6. Possom

    Possom Member

    Is Theree Ed a typo, or the name of a website?

    The living room in question is relatively small at just 2.90 m x 3.14 m.
    I am using a WB 30i combi boiler:

    with one of these vertical rads in the room (2411 W), and a TRV fitted.

    Mid terraced house with cavity wall insulation in the exterior wall.

    If I have the heating temperature on the boiler set to the "e" setting i.e. the recommended setting, this is 59 C on the boiler. With the rad turned up full I get a max of 21 C in the room. I'd really want to get it to 25 C so that that's available if it's ever needed for any reason.

    I expect the boiler is adequate in size, so presumably I'd simply need a larger rad in order to get increase in temp?
  7. Possom

    Possom Member

    So I tried this again yesterday evening as it was only 4C outside, so it was a good opportunity to get an idea as to how high a temperature can be achieved in this 9 sq m room with the following 2.4 kW column radiator and 30i Worcester Bosch combi boiler

    I set the boiler setting for the radiator heating to the "e" setting which is the recommended setting and this gave a heating temperature on the boiler of between 57C and 60C. Radiator was turned up full.

    The unheated room was at 12C, the maximum temperature I could get the room to was 22C but it took literally 4.5 hours to get to this temperature. In my opinion, this is an excessive amount of time in order to get up to 22C. Perhaps I should consider a convection radiator?

    There is no open fireplace, nor draughty floor, nor open window. I kept the room door closed throughout.
  8. Muzungu

    Muzungu Screwfix Select

    Just out of interest, what would you consider to be a comfortable temperature when relaxing?
    sparky steve likes this.
  9. sparky steve

    sparky steve Screwfix Select

    Have to agree. Lost count of the times i’ve been carrying out work at a property during the winter months and the occupants have the heating blasting and they are dressed in shorts and t shirts.:confused::eek:
  10. Possom

    Possom Member

    The 22C which it got up to seemed fine. Though since it's a small room, I'd like it to get up to this temperature much quicker than the 4.5 hours which it took. I'd also like it to have the ability to get to 25C in case this is ever required, for example, for elderly relatives.
  11. sparky steve

    sparky steve Screwfix Select

    Have you considered not letting the room temp getting so low? Set the temp to a more comfortable level & maintain via thermostat at selected level.
  12. Muzungu

    Muzungu Screwfix Select

    Ok, it's all personal preference. We never set ours to higher than 19.5 and then only in the evening, it will then overshoot to 20.5 which to us is warm. Everyone is different.
    Possom likes this.
  13. Possom

    Possom Member

    Yes, that is an option on occasion, though next winter (after many of will have been vaccinated) and I get back from work late and the room is at 12C, then with the current setup it will take 4.5 hours to get up to 22C, by which time I'll already have gone to bed.

    As far as I'm aware, convection radiators are known for heating rooms up much quicker than column rads?
  14. Muzungu

    Muzungu Screwfix Select

    Given the size of the rad it does seem to be taking longer than I would have thought. I have a much smaller column rad in the back living room which is about the same size as yours and it is fine, ancient combi boiler.

    How hot is the rad getting? As another post says, you shouldn't be able to hold onto it for more than a few seconds when it's on full, not exactly scientific but indicative of how efficient it is.
  15. Possom

    Possom Member

    Yes, it was warm enough that I wouldn't be able to hold onto it for more than a few seconds, and the rad was warm all over.

    If the rad is an adequate size for a 9 sq m room, then I think I shall put the issue down to the single glazing. It would appear that there must simply be large heat loss through this.
  16. Muzungu

    Muzungu Screwfix Select

    Sounds as though it's working fine though I am still surprised how long it is taking to warm the room. The single glazing will make a big difference.

    Stating the obvious perhaps, but you could also try bleeding it?
    Possom likes this.

Share This Page