Will a comibination, solar hot water system, duct sealing system and radiant barrier for the attic worth the investment?

Asked by Felicia Corbett
Laveen, AZ

We live in Arizona, specifically the Phoenix area, also known as The Valley of the Sun. Our two-story 3,300 square foot home is nine years old. The salesperson says we can save approximately 50% off our utility bill by purchasing the package which includes Solar Hot Water System, Duct Sealing System, Radieant Barrier for the attic and a 10 year AC tune-up program. I'd like to be more green; however, I don't want to lose money on this investment. Is it worth my while?


Answered by Doug Garrett

Jarrell, TX

Building Performance & Comfort, Inc.

April 29, 2014

Interesting package. I doubt the 50% claim, but it will likely get you to 25%-30% depending on your usage pattern. First, what type of radiant barrier are they proposing? If it is the spray on paint type, don't do it. The effectiveness of RB is a function of the emissivity. Real foil RB's have an emissivity of 0.05, blocking 95% of the radiant heat transfer. Paint on RB's are usually only 0.60. Not nearly as good and that is with perfect application, which doesn't happen in the field. The track record of these retrofits is just plain bad. Duct sealing if your ducts are in a ventilated attic is almost always cost effective. You might first have your ducts tested. Good duct sealing has been a building code requirement in many areas for years and yours may already be tightly seaqled. Solar thermal water heating can be a good idea in your climate zone. But the payback depends on how you heat your water. If it is with electricity, then you will get a pretty fast ROI, but if it is with gas, the ROI gets much longer due to the greatly reduced cost of gas. Ask you local utilit6y or the Governors Energy Office for advice. I've done some consulting with both in the past and they are knowledgeable.

Tagged In: solar water heater, radiant barrier, ductwork

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