My house has no insulation. It is brick on the first floor and wood on the second floor. The inside walls are lathe with expanded metal and cement plaster on top
Hi Maria,
That is a great question with a couple of different answers, primarily dependent upon budget and if other projects are scheduled.
The principles of building science tell us to address insulating a home in a specific order.
First, you must create an effective air barrier (more on this later), because insulation does not function well unless it is directly in contact with an air barrier.
Then, you want to upgrade the attic first, crawl space second, and only address walls/windows/doors if needed.
I live in a mild climate (Santa Barbara), where windows/walls can usually be left alone, but I believe it gets much hotter in your neighborhood. Given that is true, wall insulation and windows would generally be good investments for you.
However, if over-heating is a problem, it would certainly be worth looking into shading strategies (like overhangs, trees, trellis, etc.) first.
http://greenhomeguide.com/askapro/question/how-should-i-add-insulation-to-my-87-year-old-house