Cold room - Move radiator?

FreeBear

Doozergirl said: There is a good webpage here to calculate and recommend the size of radiator you should have and it gives you options depending on the insulation in the room.    

https://www.bestheating.com/btu-calculator

I would concur with greensalad. That particular calculator is not the best...

This one from Stelrad, although not perfect, asks a few more questions including delta T (Δt) which is important if you are using low flow temperatures - https://starsapp.co.uk/basic-heat-loss-calculator/

ComicGeek

None of the calculators are any good - they never allow for correct ventilation rates, for heat up periods, for correct internal design temperatures etc. Are they assuming 18 degrees maximum for bedrooms (which should be 21 degrees if not just used for sleeping), external air temp of only -1 degrees, no allowance for heating up from cold etc.

I'm not convinced that any of them are any better than just applying a W/m2 rate to rooms. The calculation may look more sophisticated by asking lots of questions, but a more complicated calculation that uses incorrect inputs is still wrong - every now and again it might get the right answer by having 2 errors cancel each other out.

Proper heat loss calculations are simple, I really don't know why those online calculators can't ask better questions to get a more accurate result. Calculate ventilation heat loss, sum up all individual heat loss elements, then apply the heat up margin.

Doozergirl

ComicGeek said:

None of the calculators are any good - they never allow for correct ventilation rates, for heat up periods, for correct internal design temperatures etc. Are they assuming 18 degrees maximum for bedrooms (which should be 21 degrees if not just used for sleeping), external air temp of only -1 degrees, no allowance for heating up from cold etc.

I'm not convinced that any of them are any better than just applying a W/m2 rate to rooms. The calculation may look more sophisticated by asking lots of questions, but a more complicated calculation that uses incorrect inputs is still wrong - every now and again it might get the right answer by having 2 errors cancel each other out.

Proper heat loss calculations are simple, I really don't know why those online calculators can't ask better questions to get a more accurate result. Calculate ventilation heat loss, sum up all individual heat loss elements, then apply the heat up margin.

There's a job for you there! 

ComicGeek

Doozergirl said:

ComicGeek said:

None of the calculators are any good - they never allow for correct ventilation rates, for heat up periods, for correct internal design temperatures etc. Are they assuming 18 degrees maximum for bedrooms (which should be 21 degrees if not just used for sleeping), external air temp of only -1 degrees, no allowance for heating up from cold etc.

I'm not convinced that any of them are any better than just applying a W/m2 rate to rooms. The calculation may look more sophisticated by asking lots of questions, but a more complicated calculation that uses incorrect inputs is still wrong - every now and again it might get the right answer by having 2 errors cancel each other out.

Proper heat loss calculations are simple, I really don't know why those online calculators can't ask better questions to get a more accurate result. Calculate ventilation heat loss, sum up all individual heat loss elements, then apply the heat up margin.

There's a job for you there! 

I currently get paid quite well doing heat loss calcs for large schemes, so no real incentive for me to create a tool that does it for free. But perhaps when I eventually retire to a Caribbean island...