Replace old windows with energy efficient units.
Insulating old roofs.
Attach 1 inch foam board insulation.
Install siding over the insulation.
They are often advertised as a diy option but those who have done it suggest that it requires skill and experience to do well.
The other option is loose fill or blown insulation.
U value 0 38w m.
With an assumed pre existing u value of 2 23w m the best options are as follows.
Suitable insulation includes natural fibre based products made of sheep s wool or hemp as well as mineral wools.
There is a good deal of controversy around these systems.
Permeable insulation works well with old buildings that breathe.
Available in both foam and rigid form choose the board type.
If you want to avoid internal changes you can do so by insulating externally.
Equally the reverse is true.
If you do have existing roof insulation the first thing to do is to check the depth.
Plasterboard 50mm pur insulation in 50mm timber stud with 50mm vented cavity to the existing wall.
If there is only 25mm of insulating material then this is likely to date back to the 1970s as this type of.
Alternative options for insulating old roofs one modern option for existing buildings is sprayed foam.
Insulation board should be added between the old and new roof systems to ensure proper insulation and to reflect heat from the outside.