Customers always ask us about the potential energy savings from doing the various energy efficiency upgrades to their homes (adding more insulation, duct sealing, air sealing, shade screens for windows, radiant reflective house paint, flat roof radiant reflective paint, etc.). This is a great question but one that is sometimes hard to answer directly.
There is a lot of data on each of these products but that data can often be a bit misleading. If you added up all the potential savings from each product, according to the manufacturers, you could easily save over 120%. That number is obviously incorrect. Even websites from the utility companies and energystar don’t always see eye to eye on the potential savings.
From all my years of actually doing the work, researching various data sheets, and tracking the energy savings we have seen from our customers, most homes can expect to see about 20-35% reduction in their energy bills by: 1) making sure your duct work is sealed properly (most homes are losing 20-30% of their heated or cooled air through the duct system), 2) have a proper air seal from the attic space to your living space in your house, 3) bring your insulation levels up to at least a R-38 rating for the Phoenix, AZ area (for suggested r values in other areas, see energystar.gov), and 4) have shade screens or a good window film to block the extreme heat.
We’ve had some homes save over 40% just by painting their flat roofs with a radiant reflective roof coating. We’ve had some homes save 15-20% by painting their house with a radiant reflective paint. We’ve had some homes save over 50% just by sealing their ducts and adding insulation. Now how much of that savings was because of the product vs some external factor that caused a change in energy consumption (like change in temperature or lifestyle change)? I have some idea but it is nearly impossible to measure it exactly.
Where will your home fall on energy savings, I have no idea. The best I can do is give you an estimated range once we do an Energy Audit. The one thing I can tell you with certainty is if anyone tries to tell you exactly what you will save, run… and please run to us!