I am converting a garage to a usable room and am researching different options when it comes to insulation. I know more insulation is better, however there is a point where adding more insulation will never reduce the heating bills by enough to pay for itself.
Assuming the external dimensions of the room is 5.5m long, 3.5m wide and 2.5m high, this would give a surface area of:
- 5.5m * 2.5m * 2 walls = 27.5 m2
- 3.5m * 2.5m * 2 walls = 17.5 m2
- 3.5m * 5.5m * 2 (1 roof and 1 floor) = 38.5 m2
The total surface area would be 83.5 m2
If 75 m2 had a 0.33 w/m2k and 8 m2 has a 1.5 w/m2k (windows and doors), would I be right to assume that this would give a 37 w/k for the entire room?
If the difference between the internal and external temperature was 10 degrees C, I assume that I'd need 370 watts to heat the room. If the walls/ceiling/floor had a 0.22 w/m2k, then without listing all the calculations I'm assume this would be 270 watts, therefore a saving of 120 watts or about £0.03 of electric per hour.
Firstly, I was wondering if someone could please confirm if I'm at least on the right track please?
Secondly, any recommendations on how I can work out the division of lost between the walls, floor and ceiling please?