Habitat’s Weatherization Program:  Small changes make a big difference

By Rocky Font-Soloway

“Brrr, why is it SO COLD in my house?  Why is this room colder than that one?  Whew, my gas bill is through the roof this month!”  If you’ve heard yourself saying something similar this winter, your home might benefit from weatherization upgrades.   Habitat Philadelphia’s Weatherization and Home Repair Program (WHRP) does something similar, partnering with low-income homeowners to provide them with critical weatherization upgrades that they’re unable to pay for themselves—and which lead to lower energy usage and utility bills, and a more efficient home.  We’re nearing WHRP’s two year anniversary, and to track our progress we recently compiled data showing how successful our upgrades have been for homeowners and their wallets.

In the WHRP’s very first round of projects (Spring 2012) we provided a standard home weatherization package for four Habitat homeowners who have lived in their houses for between 10 and 20 years.  These improvements ranged from identifying and sealing air gaps, to insulating and optimizing the home’s heating system, to upgrading fixtures and appliances to be more energy-efficient (installing low-flow showerheads and aerators on faucets, or replacing incandescent light bulbs with CFL bulbs).  We then compared the change in the homeowners’ energy usage before and after the improvements were made (determined comprehensive energy audits done before the work began and after it was finished).  What we found was that these weatherization improvements helped families save significant energy—and significant money.   Here were a few highlights:

  • Homeowners reduced their heating (natural gas) demand by an average of 25%
  • One homeowner reduced heat demand by 36%
  • Homeowners reduced electric demand by an average of 5.5%
  • One homeowner reduced electric demand by 36%

(Note:  Scroll to the bottom to see the full results and details about our methodology.)

We were thrilled to see such big results, which were the results of our WHRP team’s four central focuses.  Let’s look at how each focus makes homes safer and more efficient—we’ll also list easy, effective ways to weatherize your own home.

  1. Thermal improvements: 

Do you ever notice a cold draft getting through your front door or windows?  This is a good example of air leakage—when exterior air enters the home or conditioned air escapes.  Our goal is to find and seal these gaps, and to add insulation to key cold spots in the house, like the attic.

-Weatherize your own home:  install weather-stripping around doors (including door sweeps) and around windows; use caulk or spray-foam to seal gaps; add extra fiberglass insulation to the attic.  These inexpensive changes often have a big benefit.  For example, a single-pane wooden window (common in older Philadelphia houses) tends to be a significant source of air leakage.  Replacing it with a new double-pane vinyl window can cost hundreds of dollars—or, you can buy weather-stripping (typically costing no more than $10) from the hardware store.  When installed correctly, weather-stripping around windows blocks air leakage almost completely—meaning that the air that you pay to heat will stay inside, where you want it.

Adding extra insulation to the basement walls. Rigid foam insulation is inexpensive, mildew resistant, and keeps heated or cooled air inside your home.


Insulating basement walls with rigid foam

Adding extra insulation to the basement walls. Rigid foam insulation is inexpensive, mildew resistant, and keeps heated or cooled air inside your home.

  1. Repairing/replacing heating and air distribution systems:    Because we live in a relatively cold climate, heating our homes and water is a large chunk of our energy bills—so it’s important that heating systems function well and are appropriate for the size of the home.  Our WHRP team tunes old furnaces, boilers, and hot water heaters, or replaces them when needed.  We also seal leaks in duct work and insulate hot water pipes, so that hot water and hot air can travel from the furnace/boiler/heater to the faucet or the vent without losing heat on the way.

Weatherize your own home:  insulate the hot water pipes that you see in your basement and under sinks.  You can find inexpensive pipe insulation “sleeves” at any home-improvement store.

A volunteer wraps basement hot water pipes with insulation–an easy, inexpensive and effective way to save on gas bills.

wrapping hot water pipes with insulation

A Habitat volunteer wraps basement hot water pipes with insulation–an easy, inexpensive and effective way to save on gas bills.

  1. Upgrading energy-using equipment:

From turning on the air conditioning to taking a hot shower, we’re using energy in our homes almost every waking hour.  WHRP installs upgraded fixtures and appliances that reduce the amount of energy we use in daily life, such as programmable thermostats, dual-flush toilet mechanisms, and Energy Star refrigerators and stoves.

Weatherize your own home:  replace incandescent light bulbs with CFL bulbs; install low-flow aerators on faucets; and install low-flow showerheads.


  1. Education to the homeowner:  This is our biggest investment.  We build strong relationships with homeowners, explaining how their home works and where it’s losing energy.  Homeowners work with us on almost all of the weatherization projects in their home, and this is a perfect opportunity to explain how each of the above tasks saves them money and energy.  We also supply them with educational materials about how best to save energy in their homes—because no matter what improvements are made, individual lifestyle choices are just as important for lower bills.

Weatherize your own home:  Sign up to volunteer with us at weatherization workdays, when you can work on these tasks with us in homeowners’ houses.  You’ll be able to practice the techniques, see the materials and skills you need, and ask any and all questions about weatherization and home energy use.   Come join us!  Visit our website at www.habitatphiladelphia.org/get-involved to learn more.

A Habitat volunteer and homeowner discuss an energy-saving programmable thermostat that they’re about to install.

Green building techniques - Installing a programmable thermostat

A Habitat volunteer and homeowner discuss an energy-saving programmable thermostat that they’re about to install.

One of our primary goals is to identify the weatherization techniques that are cost-efficient and result in big energy savings.  Lowering the total time and cost of each home weatherization project means that we can partner with more homeowners and complete more weatherization packages with our existing funds and resources.   We are thrilled with the growth of our Weatherization and Home Repair program over the past two years, and we look forward to providing critical repairs and improvements to many more Philadelphia homeowners in need in the coming years.  Learn more about our Weatherization and Home Repair Program here, and see how we incorporate energy-efficiency into all of our new homebuilding projects here.


More information on our home energy-usage study:

Each of the four homes we measured received a standard package of weatherization items like those listed above along with a few items specially tailored to the needs of that home, determined through a comprehensive energy audit.  We tracked the family’s energy usage (natural gas and electric) for the year prior to the Habitat weatherization package, and for the year following.  Then we normalized the seasonal numbers—that is, we calculated the energy used and compared it to weather patterns for that year.  What this means is that the savings you see below are represented as if the 2011-2012 year had the same exact weather as the 2012-2013 year.

Using a special “Blower Door” device to measure the air leakage inside a house. Looks a little like E.T. but it sure is useful!

Conducting a blower door test to measure air leakage

Using a special “Blower Door” device to measure the air leakage inside a house. Looks a little like E.T. but it sure is useful!


Gas Usage (ccf) Electric Usage (kWh)
2011-2012 2012-2013 Change Adjusted change 2011-2012 2012-2013 Change Adjusted Change
Family 1 778 750 -4% -22% 4372 5132 17% 23%
Family 2 549 480 -13% -28% 4224 4486 6% 11%
Family 3 541 420 -22% -36% 5900 4465 -24% -20%
Family 4 115 122 6% -13% 4272 2612 -39% -36%
HDD 3567 4358 22% -25% 1383 1321 -4% -5.50% CDD


Some questions you might be asking:

Why are gas bill savings so much higher than electric bill savings?

Because Philadelphia’s winters are harsher than our summers, residents generally spend more money on gas heating in the winter than electric cooling in the summer.  Therefore the money saved during the winter due to the lessening of conditioned air leakage is typically much greater than the electricity saved in the summer.  The biggest electric savings was in a home in which we upgraded the hot water heater from a regular electric to a hybrid electric.

Why did some usage increase?

Ultimately, energy usage is based in homeowners’ lifestyle and decisions.  We can speculate that perhaps energy usage increased because another person moved into the home, and therefore lights were used more often.  Or it’s possible that someone in the household retired and began spending more time in the home, using the heat more consistently.  Those changes are not taken into account in these numbers, but as we track homeowner energy usage over more households and longer periods of time, the numbers may become more consistent and the savings more apparent.

Can I see these numbers in my own electric and gas bills?

For most gas providers, the second page of your monthly bill includes a graph that shows your gas usage over time.  Unfortunately, the information does not normalize last year’s usage to this year’s (it doesn’t take changing weather patterns into account), but you can see the patterns of your usage and the months when you are spending the most money.

How can I learn how to do those DIY weatherization tasks?

Volunteer with our Weatherization and Home Repair Program and practice all sorts of weatherization techniques first-hand!  Visit our website at www.habitatphiladelphia.org/get-involved to learn more.


About Habitat Philadelphia

Habitat for Humanity Philadelphia is an independently chartered affiliate of Habitat for Humanity International (HFHI), the largest nonprofit homebuilder worldwide. Locally, Habitat Philadelphia is on a mission to transform lives and our city by building and repairing quality homes in partnership with families in need, and uniting all Philadelphians around the cause of affordable housing. Our Vision is a city where all Philadelphians live in safe, affordable homes.
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