Several of my customers I go to for work are insulation companies like SIG and Minster etc, so have a plethora of stuff available.
I don't want to lose too much inside space, and have door surround only an inch from the wall in most cases, so is it worth using the 25mm thick polystyrene covered plasterboard or what and how much does anyone suggest I might gain in heating loss savings?
Personally I wouldnt use polystyrene. In a fire its deadly, and you get a good bit more insulation by using hard faced PIR foam sheets.
Savings will be whatever you've been losing thru the walls minus what you'll continue to lose. You'll need to know the wall construction type & area, then calculate as explained on the wiki.
NT
If you use PIR foam boards, then their K value is about 0.025 W/mK. So even an inch would give you a U value of around 1, which is less than half the heat loss of a normal 9" non cavity solid brick wall.
So add that to such a wall, and instead of losing energy at 2.2W for every square metre and every degrees C difference, that would come down to about a third of that. (if you estimate 30% - 45% of your total heat loss is through the walls that could translate into 10% to 15% reduction in space heating fuel use)
Oh dear! Puts it into perspective doesn't it :-) Must do something about it. Well, in the Spring maybe....
W/mK. So
1" of PIR bonded to plasterboard (overall about 35 mm) on the outside walls only will make a noticeable difference to the room. Did the end wall (just two 8x4 sheets) of the lads bedroom and that room was instantly warmer and more comfortable.You'll get most benefit during the winter when the temperature gradient across the wall is highest and thus the heat loss highest.
HomeOwnersHub website is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.