I have now received the first empirical evidence that replacing your old windows & doors can have an impact on your utility bill.
Our house is one of the standard, ranch-style houses that were popular in the SF Bay Area in the late 1960s. It had the original, single-pane aluminum windows, and hollow-core doors.
We replaced the exterior doors a couple of years ago, but we just completed last month the installation of new, double-pane windows throughout the house. We also replaced the large sliding glass doors in our living room.
It’s a large expense, and while you are comforted somewhat that the money will come back to you when you sell the house, that seems like it will be very hard to prove. As a result, I’m really glad to see that our heating bill (our kerosene heater is gas-driven) for the first cold month of the year is actually quite a bit lower than last year.
Of course, the low gas bill could also be the result of us doing less cooking at home around the birth of my second son on October 30th. I’ll keep monitoring, but hopefully, the energy savings promised around this type of improvement turn out to be accurate.