Btu size?

[willp2]

how do I size the btu needed for heating conservatory, 4m x 7m standard 3m ceiling hieght

 

[gas4you]

I would treat it as a normal room add the extra area of the glass then add 50 %.

 

[Space cat]

1) Work out the total area of glass in square metres. Anything else will be trivial by comparison.

2) Decide how warm you will want it on the coldest day of the year, eg 20° inside but -10° outside = 30°.

3) Multiply the results of one and two by 2.5 - or 5 if single glazed!

4) You now have the answer in kilowatts. Be prepared for a shock, eg 60 sq m x 30° x 2.5W/sq m/deg = 4.5kW!

5) Divide by three and multiply by 10000 to get the answer in btu per hour.

 

[giblets]

Easier to multiply kW's by 3412 = BTU/hr

 

[Space cat]

Easier to multiply kW's by 3412 = BTU/hr

Fair comment (and more accurate too) if you're using a calculator.

 

[John M]

Tiz a lot easier to stick to Kw's ....... Decimalisation wasn't a complete cods up ya know

 

[chrishutt]

Tiz a lot easier to stick to Kw's .......

Better still kWs. Small k, capital W and no apostrophe.

 

[John M]

Tiz a lot easier to stick to Kw's .......

Better still kWs. Small k, capital W and no apostrophe.

 

[Space cat]

Decimalisation wasn't a complete cods up ya know

This is true. SI units have a lot going for them. When I first learnt physics we had to work in grams, dynes and ergs - and calories too! There were BTUs of course and also CHUs (centigrade heat units before you ask). As if this wasn't confusing enough, we learnt that a food calorie was worth 1000 of our calories!

But that's nothing compared to what my father had to put up with. He was doing a part time degree in physical electronics at the time and he learnt that there were two different kinds of volts and amps!