Real world example #1: Duct testing/sealing and payoff

Up until now we’ve been telling you that an energy audit and subsequent weatherization will pay for itself in 2-3 years. We have years of data from Energy Star and the Low Income Weatherization program to back this up. But now it’s time to give you real examples of ways that our clients have saved and will save money from applying the results of an energy audit to make their homes more energy efficient.

Real world example #1: Joe Suburban Homeowner Guy from Cary

The client in this first example owns a 3200 square foot home in one of the most densely populated suburbs of Raleigh, built in the 90s. It’s one of many in a neighborhood of homes built at the same time. These homes were not built to Energy Star standards and probably went up very quickly. It’s unclear if one builder built all of them or if a number of builders participated in this subdivision.  If you live in the greater Raleigh area you know that there are many neighborhoods like this in Cary, Apex, North Raleigh, Wake Forest, Holly Springs, and other suburban pockets.

We did a comprehensive home energy audit and were also contracted for follow-up weatherization. This customer’s energy company is Progress Energy, so he qualified for the duct testing and duct sealing rebate.

One of our suggestions for weatherization was to seal the home’s HVAC ducts. We did some other weatherization as well, but for this case study I want to focus on the duct testing and sealing.

Here’s what the homeowner paid for the audit + duct sealing, minus the rebates from Progress Energy:

$570

Plus, he’ll also get a $30 tax credit from the federal government. 

We calculate that his heating and cooling costs were $2600/year.

When we tested his HVAC ducts we found that they had 26% leakage. That’s right – 26%. What this means is that 26% of the heated or cooled air wasn’t reaching the house.  Every time the heat pump kicked in – either to heat or cool the home – only 3/4 of what should have been going in was going in.

Unacceptable, right?

Believe it or not, most homeowners experience 20-30% leakage in their home’s HVAC ductwork, and some research even puts it as high as 43%. So our homeowner, at 26%, was experiencing average energy loss through his ducts. But who wants to be average? Especially when it comes to wasting energy!

After sealing this homeowner’s ductwork, we re-tested his ducts for leakiness and found that we’d reduced the leakage to 4%. 74% capacity to 96% capacity. Not perfect, but darn close.

From his ducts alone, he should save, very conservatively, at least 10% on his  energy bills. We’ve looked at many reports that state duct testing/sealing can save more like %20-%30 on heating and cooling costs. 

We estimate that with the money this homeowner will save in energy costs from his HVAC system alone he will have a 100% return on his investment in the audit and the duct sealing within two years. This doesn’t count the other energy efficiency work that we did on the home, and it’s using today’s energy costs. If rates go up, the return on his investment will be even faster.

Finally, it’s worth pointing out that we’re using the savings on the duct work to calculate the pay back for the price of the entire audit – an audit that pointed out many other ways the homeowner could save money. 

A win-win for the homeowner, no?

Tags: apex, cary, chapel hill, duct sealing, durham, energy audit, pittsboro, progress energy rebates, raleigh, return on investment duct sealing, weatherization contractor

This entry was posted on Sunday, February 28th, 2010 at 1:36 pm by Adrienne Bashista and is filed under all blog posts, ducts, energy audits, home performance, real world example, saving energy/saving money, tax credits and rebates. You can follow any responses to this entry through the RSS 2.0 feed. Both comments and pings are currently closed.