I live in Southern California. My house tends to lose heat pretty fast and does not stay very much warmer than a couple degrees outside overnight.
The attic looks like it has 2.5 inch fiberglass insulation blankets R 7.4. The coverage is maybe 85% covered. Some areas are thinned or missing completely and all blankets are pretty dusty up there. We have a lot of ceiling lights and speakers which probably leak air.
My impression is R7.4 is too low for this area. What is a good R value to use instead? Should I layer or completely replace?
When I eventually do this I’ll try to seal air gaps if I can identify them and roll out the blankets myself.
I know the walls are not insulated so I’ll have to hire for that job.