Replacing Leaky Windows

Energy-conscious carpenters trades old windows and doors for more sophisticated, airtight alternatives.

Jeff Wilson could feel the cold air blowing in through his old single-pane windows. When he touched the glass in winter, the surface was freezing cold. Warm air from inside would form beads of condensation on the windows, which dripped down to the painted sill and caused mold growth, even in the dead of winter.

"If it was windy, you could actually feel breezes coming through," Jeff describes, adding that the leaky windows ushered in southeast Ohio's stagnant summer humidity, causing the air conditioner to work overtime.

Several years ago, Jeff replaced four windows, opting for double-pane glass. "Double-pane is fairly standard now, and those are good," he says, defending his first window replacements. "But the question is, are they going to be good enough in the long haul?"

Jeff will keep those double-pane windows and enhance his home by replacing the rest with the industry best: triple-pane, gas-filled windows. That includes nine more antiquated, leaky windows, plus the front door — and seven windows and three more doors in the new garage/addition.

"I feel strongly that you shouldn't rip out something you did just five years ago and redo it," he says of his thrifty-green approach. "Instead, I built on what I had already done."

Tighter Windows and Doors

As their name suggests, triple-pane, gas-filled windows provide three layers of glass with krypton or argon gas between layers. This gas serves as insulation, reducing heat transfer between panes. The frame material is also important. Jeff opted for vinyl-framed windows, which provide better insulation than metal-clad wood frames. Additionally, the windows have a warm-edge glazing, meaning high-density foam and high-grade silicon sealant is applied between the window and frame rather than a simple metal spacer. This prevents condensation at window edges.

"If I put my hand on the window, it feels only slightly cooler than the temperature of the room, which means the bitter cold air outside is not sucking the heat out of my house," Jeff explains, noting that the layers of glass spaced with krypton gas prevent this air exchange.

Proper window installation is as important as buying the best window. Follow window manufacturers' instructions for how to install, caulk and tape windows to prevent any gaps, Jeff advises.

Jeff replaced three doors in the original house, and installed three doors in the new garage/addition. He opted for fiberglass, foam-filled doors that will maintain the air seal he worked hard to accomplish through window replacements and insulating the walls. The front door is wood-framed with triple-pane, gas-filled art glass detail — a custom piece that is airtight and aesthetically pleasing.

Replacement on a Budget

Replacing every window in your home might not fit your budget, so split this project into chunks you can manage.

  • Identify windows in the worst condition. That's often those on north- and west-facing sides of the house that take a beating from Mother Nature. "Replace windows one wall at a time," Jeff suggests. "Make a plan and break it down based on what you can afford. You don't have to do everything all at once."
  • Install with care. Follow manufacturers' instructions carefully to get a tight air seal. Or rely on a professional for this task.
  • Buy as much as you can afford. "Look at warm-edge glazing and triple-pane, gas-filled windows," Jeff advises. "Aim for as high-quality windows and doors that you can, because you don't want to replace them anytime soon." The windows Jeff chose have a 50-year warranty.

Boosting Efficiency With Windows and Doors

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Jeff Wilson replaced half of the windows in his 70-year-old Cape Cod home just five years ago, upgrading from single-pane glass to more efficient double-pane windows. Meanwhile, as Jeff greens his home top to bottom with a Deep Energy Retrofit (DER), he addresses nine leaky windows and a front door, choosing today's gold standard: triple-pane, gas-filled windows.

Triple-pane, gas-filled windows provide three layers of glass and are filled with krypton or argon gas. The gas serves as insulation, preventing heat transfer between panes. This cross-section view shows the technology Jeff chose.

The home's bay and dormer windows are replaced with triple-pane, gas-filled windows that have a warm-edge glazing. This means high-density foam and silicon sealant is applied between the window and frame rather than using a simple metal spacer. This technology will prevent condensation at the window ledge, which leads to mildew and rotting.

You can choose the most efficient windows on the market, but if they aren't installed correctly, you've just wasted time and money. A tight air seal is imperative. Windows must be caulked and taped to prevent any gaps.

New windows are installed in the garage addition using proper sealing methods to ensure a tight air seal and optimum efficiency.

Eco-friendly doesn't have to mean ugly. Jeff chose custom decorative glass with the same triple-pane, gas-filled construction as other windows in the home. This helps retain the Cape Cod charm of the home.

These foam-filled fiberglass doors provide a tight air seal.

Next Up

What It Costs to "Green" an Existing House

From building an addition with solar paneling to laying new shingles for the roof, Deep Energy Retrofit is not cheap.

Retrofitting an Existing Roof for Energy Efficiency

The lid of Jeff Wilson's Cape Cod was leaking big time. A new roof bolstered with insulation more than doubles its energy efficiency.

Air Sealing a Drafty House

Learn techniques to more than double your home walls' energy-efficiency rating.

Home-Energy Audit Saves Money

Find out how a professional inspection can reduce a home's energy use and utility bills.

Replace Old Heating and Air Unit With New Efficient HVAC System

A superior HVAC unit balances humidity and boosts efficiency.

Why R-Values Matter in Energy Efficiency

R-value measures the ability to prevent the transfer of heat; the larger the number, the harder that insulation is working at preventing heat conduction.

Repel the Sun's Heat With Radiant Sheathing

Improve energy efficiency by putting insulation beneath roofing material.

Solar Panels Help Save on Power Bills

Harnessing electricity from the sun will help cut utility costs.

Building an Energy Efficient Home Addition

A homeowner makes sure his retrofit of his 70-year-old home addition saves energy.

Home Energy Audits and Surveys

When doing an upgrade, start with a solid home energy survey or a professional audit.
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