Insulation value of plasterboard, without insulation?

[vexille]

I have almost finished fitting plasterboard in all the house. Everything apart from the bathroom has mineral wool insulation in the walls.

The reason wall insulation was not used in the bathroom, was because it was my first room to renovate. Read that because it was a timber frame building, that I should not use insulation at the time. I now know this to be incorrect and only applies to some historic buildings.

When I moved in, none of the walls had insulation and had holes in the walls.


My thought now is. The bathroom is fairly small, but three of its walls are outer walls. Over all how will this effect the heating bill in winter? Also what are the insulation values of standard plasterboard?

 

[PrenticeBoyofDerry]

A standard 12.5mm PB has a thermal resistance of 0.7m²K/W
and the 9.5mm equals 0.5m²K/W
15mm =0.8m²K/W
If you have cavity wall, get the wall injected, you may get lucky and get it free of charge.

 

[freddiemercurystwin]

The insulation values of plasterboard on its own are in real terms pretty rubbish. The room will be freezing in the winter. Its not just about the heating bill though, you are likely to get problems with condensation especially in a bathroom. Unless you have tiled and finished i would be ripping the boards off and adding insulation if it cannot be done from the outside. Or maybe adding insulation to the inside and re-boarding though this is fraught with issues aswell.