Rad size and attic requirement

[marsaday]

Two questions here. I have bought a double rad with single fin which is 1800 x 600 and it produces 10k BTU's. When i boughti it ages ago and thought nothing of it, but since then i have come round to thinking single fin rads cant go that high. Or am i wrong here. It did say on the packaging the output so it must be right. Just wondered if anyone can clarify.

This rad is supposed to go in our attic which is 3.6m x 6.5m, but i reckon i can use a much smaller rad up here. What do you think ? I ask because our didning room rad is under sized and this big 1800 rad would fit a treat in here. so i am thinking of swapping the bed rad for the dining rad. I will do it, if you think we dont need 10kBTU in the attic bedroom. We already have a 6k BTU rad in ther hall and a bathroom rad up here as well.

 

[AWheating]

the size of radiator needed will depend on many factors, heat source, size of room, the u values of all walls (including ceiling,floor,doors and windows), Air change rate and so on..... once you have this information you can calculate the required output.

 

[diamondgas]

marsaday, check out this site Radcalcs radiator btu sizing site Should help you with sizing...

Regards SCon rads and 10k btu's ... 2600x700mm K1 gets you there ... Wouldn't like to carry it up to the loft though!!!

 

[marsaday]

Well this rad is very heavy. But isnt a loft area different to the other areas of the house. These calcs only have options for lounge/kitchen/bedroom etc.

I thought the loft area will need much less heating based on the height of the space - top of house- and the overall height of the room. The room is in a simple pitched roof, which goes up to 3m in height, but the rest of the space is sloping downwards.

So i was thinking use a bedroom option on the calculator and then just divide the outcome by 2 because the room space is half that of a normal room of the same size.

The roof is insualtaed to 125mm celotex and the walls have been insulated up here as well - not like rest of house as an old solid brick building.

the calculator says i need 10k BTU, but i thought 6k would easily be enough.

 

[diamondgas]

I'd most likely be looking to half what the calc kicks out because of the shape. So you'd be right at 6k... End of the day you only need that amound in the dead of winter...! I know there's an exact science to sizing which you could go down. If it were my home I'd be happy with a single convector knowing that if it doesn't do the job in the coldest of winter I can swap it for something bigger!! lol .... If you hang on I'm sure someone will give you better advice regards actual heat requirements...

 

[marsaday]

That sounds about right i reckon. Basically the 2 rads i have have a difference of 1.5 Btu and so i think it wil be better to have the bigger one in the dining room and the smaller in the attic bedroom. The smaller one is still pretty good and gives 8k btu so i reckon it will easily be enoght for the attic.

 

[AWheating]

the volume of the space may be smaller but you have a much larger heat loss to outside through the roof, try using the heat loss calulator on city plumbing website and put in uninsulated roof as ceiling, let us know what you get?. you could try and save money and insulate the roof? but make sure you vent.

http://www.trademate.co.uk/Services/HeatLoss/default.asp?_brand=CP

 

[diamondgas]

the volume of the space may be smaller but you have a much larger heat loss to outside through the roof, try using the heat loss calulator on city plumbing website and put in uninsulated roof as ceiling, let us know what you get?. you could try and save money and insulate the roof? but make sure you vent.

Hi AW, see post (5) ... He's insulated the whole loft by sounds of it. Good thought regards ventilation! :cool4:

 

[AWheating]

ah.... good spot steve, you are paying more attention then me then!

 

[marsaday]

It gives me heat loss of 2650 btu,s , but i have put down the room height as being 1.5m (3m divided by 2). Also the insulation only goes up to 100mm and i have 125mm, so i think heat loss will be even less.

this means an 8k btu rad will be fine. So i will fit my dining room rad up here and use the 10k btu new rad in the dining room.