DIYbanter - View Single Post

wrote:
120w wont achieve anything in any building.

If youre going to go with electric, and just happen to have a big stack
of old fridges and freezers, building them into one wall would pump
external heat in as well as getting the heat from the leccy.

It's a Wendy House.
I'm bored.

Let's say said wendy house is 2m*1m*1.5m.
So, walls 9m^2, roof 3m^2 (pitched), floor 2m^2.

Starting with the floor, we have a perimeter of 6m, and an area of 2m^2.
Call it a U value of 2. (extrapolating off the end of a table.)

Walls.
I'll assume it's not got plasterboard/celotex/..., but is 1/2" timber.
Inside and outside R values total .17, and the timber is about .1, for
a total R value of .27, or a U value of about 4.

Roof.
Inside/outside Rs = .14, wood = .1, total = .24, or again about 4.

So, total roof+walls area is 12m^2, U value of 4, I make that 48W/K.
And the floor will take 2W/K, totalling up to a nice round 50W/K.
Or 2.4K above the outside temp.
While not exactly toasty, this is certainly usually noticable, and will
be significant in terms of keeping things dry.

Taking the shed to an average U value of 1 (120W would heat it by 11C)
would need about 4cm of polystyrene/...