Mears Heating Calculator

[OhGord]

Can anybody explain to me how I get the radiator output in btu, from the room heat requirement in btu, using the Mear's calculator, on the instruction manual page 5 it shows a temperature difference of 108f , I did try using their example's page 8 just could not get same figure. some assistance truly welcolme.

Thanks

 

[Agile]

No only do they work in outdated units that we dont use now but they are usually seriously over sized ( like 20% ).

I would always recommend the whole house method which seems more accurate.

Tony

 

[D_Hailsham]

on the instruction manual page 5 it shows a temperature difference of 108f

A difference of 108°F That's 42°C

I don't know of any boiler which required that differential.

 

[Agile]

I expect he is quoting a Mear's booklet and that refers to the differential between mean rad temp and the room.

Tony

 

[D_Hailsham]

I expect he is quoting a Mear's booklet and that refers to the differential between mean rad temp and the room.

If, so that's a very low differential. Rads specs are based on a 50°C differential. A 1kw rad (75/65/20) will reduce in output to 800w (67/57/20). So you would have to install a 1250W rad to give the 1000w actually wanted. This would explain the 20%+ oversizing that you mentioned earlier.