Heat loss calculations

[joe brown]

Any experienced plumbers that understand heat loss and u values that could help me out.. I am trying to work out a heat loss calc on the kitchen, I have done the lounge which is 21 degrees and i understand that if the outside temprature is -1 degrees then it makes it 22 degrees...im total aware of that and also the temprature diferences between rooms... but what happens if i am calculating my kitchen at 18 degrees and the living room is 21 degrees, does this become a -3 diference or just a 3 degree diference... when i did the lounge it was 21 and the kitchen was 18 so there was a 3 degree difference...but what happens in reverse.. also what happens when the bedroom and the bathroom are both 18 degrees and im doin a calc on the bedroom... as soon as i put 0 degree diference in my calcs everything times by a zero becomes a zero...

 

[Nostrum]

2 - equals a + so 2 - -2 becomes 2 + 2 = 4.

Your kitchen will gain heat off the living room (and living room losing heat to kitchen) so the difference is as you say -3 giving you a gain on the calculation rather than a loss.

as for the zero, thats fine because if the rooms are the same temperature then you will neither gain or lose any heat because of it.

 

[dancinplumba]

as an aside -3 outside is used and bathrooms are 22c

 

[AWheating]

the outside temp can differ, dont forget your air changes

it becomes a zero because if its the same temp on both sides of the wall there will be zero loss or gain.

 

[Nostrum]

as an aside -3 outside is used and bathrooms are 22c

Depends where you are in the country, we are supposed to use -1 down here in Devon and if you are really accurate you can take into consideration altitude as well :euro:

 

[joe brown]

Thanks everyone thats really appreciated.