Will New Windows Actually Lower My Energy Bills?

What Does ENERGY STAR Say About Window Energy Savings?

ENERGY STAR reports that upgrading to ENERGY STAR certified windows lowers household energy bills by an average of about 12%.

That is useful as a national benchmark—not a guarantee that every homeowner will save exactly 12%.

ENERGY STAR also emphasizes that window performance requirements vary by climate and that homeowners should compare actual performance characteristics rather than assuming a more expensive window is automatically more energy efficient.

Think of published energy-savings percentages as a reference point, not a promise for your individual utility bill.

Why Is It Impossible to Promise an Exact Energy Savings?

Consider two Quad Cities homes.

House A has old single-pane windows with noticeable air leakage.

House B already has relatively modern double-pane Low-E windows that are properly installed and tightly sealed.

Installing the exact same replacement window in both houses would not necessarily produce the same energy savings.

Other factors include:

• Square footage
• Number and size of windows
• Attic insulation
• Wall insulation
• Air leakage elsewhere in the house
• Exterior doors
• HVAC efficiency
• Thermostat settings
• Sun exposure
• Tree shading
• Weather
• Utility rates
• Occupant behavior

Windows are one part of the home's energy system.

How Do Windows Lose Energy?

Energy can move through and around a window in several ways.

Conduction

Heat moves through the glass, spacer, sash, and frame materials.

Convection

Air movement within insulated-glass spaces and along glass surfaces can transfer heat.

Radiation

Radiant heat can pass through glass. Low-E coatings are designed to reduce this form of heat transfer.

Air Leakage

Air can leak around operating sashes, frames, weatherstripping, and poorly sealed installation joints.

A good replacement window needs to address more than just the number of panes.

Does Low-E Glass Really Matter?

Yes.

Low-emissivity—or Low-E—coatings are designed to reduce radiant heat transfer through window glass.

During a Quad Cities winter, an appropriate Low-E glass package can help retain indoor heat.

During summer, the correct glass package can help control unwanted heat entering through the windows.

Suburban Construction offers multiple glass-performance options, including double-pane Low-E glass with argon and upgraded triple-pane configurations.

Compare Suburban Construction Window Glass Options

What About Argon and Krypton Gas?

The spaces between panes of insulated glass can be filled with insulating gases to reduce heat transfer.

Suburban's window options include argon-filled double-pane glass and higher-performance triple-pane configurations, including a krypton-filled option.

The gas is only one component of the complete glass system. Pane count, Low-E coatings, spacer design, frame construction, and installation all contribute to performance.

Do not buy a window based on one buzzword. Compare the complete glass package.

Are Triple-Pane Windows Worth It for Energy Savings?

Triple-pane windows can provide better thermal performance than a comparable double-pane configuration, but that does not automatically mean every homeowner should purchase triple-pane for every opening.

Triple-pane deserves stronger consideration when:

• You are replacing very inefficient windows.
• Winter comfort is a major concern.
• You have large areas of glass.
• You regularly feel cold sitting near the windows.
• You want higher overall thermal performance.
• You expect to remain in the house for many years.
• The upgrade cost makes sense within your budget.

But do not judge triple-pane solely by trying to calculate how many months it will take to “pay for itself.”

The benefit can also include warmer interior glass surfaces and improved comfort near the windows during cold weather.

Sometimes you feel the benefit of better glass before you see it on the utility bill.

Explore Double-Pane & Triple-Pane Window Options

Why U-Factor Matters

When comparing replacement windows, ask for the U-factor.

U-factor measures how readily a window transfers non-solar heat. In general, a lower U-factor indicates better insulating performance.

This gives you something measurable to compare instead of relying on marketing phrases such as:

• Premium efficiency
• Ultimate energy saver
• High performance
• Maximum insulation

Ask for the number—not just the adjective.

What Is Solar Heat Gain Coefficient?

Solar Heat Gain Coefficient, commonly abbreviated SHGC, measures how much solar radiation passes through the window as heat.

The appropriate balance between U-factor and SHGC can depend on climate, orientation, shading, and the specific glass package.

That is another reason to compare actual ratings rather than simply choosing the window with the longest list of features.

Can New Windows Reduce Drafts?

They can when the existing windows or installation are allowing unwanted air leakage.

But there is an important distinction between an actual draft and the sensation of feeling cold near a window.

Cold glass can cool nearby room air and increase radiant heat loss from your body, making you feel chilly even when the window is not leaking significant outside air.

Higher-performance glass can help by maintaining a warmer interior glass surface during winter.

Installation Can Affect the Energy Performance You Paid For

You can purchase an excellent window and still end up disappointed if it is poorly installed.

Suburban Construction's installation process includes custom measurement, proper fitting, shimming, fastening, perimeter insulation, flashing, sealing, trim work, operation checks, and cleanup.

Why does that matter for energy efficiency?

Because a high-performance glass package cannot compensate for significant air leakage around the window opening.

A quality window still needs a quality installation.

Review the Suburban Construction Window Installation Process

Will Replacing One or Two Windows Lower My Energy Bill?

Possibly, but the change may be difficult to see on the utility bill if those windows represent only a small portion of the home's exterior.

That does not mean replacing a few windows is pointless.

If one bedroom has a badly deteriorated window, replacing it can improve comfort and address that specific problem even if the effect on the whole-house utility bill is modest.

Whole-house energy savings and room-by-room comfort improvements are not the same thing.

Should I Replace Good Windows Just to Save Energy?

Not necessarily.

If your existing windows are relatively modern, tightly sealed, operating correctly, and already have good insulated glass, replacing them solely to chase a small improvement in energy performance may not provide the best return on your home-improvement dollars.

Replacement deserves stronger consideration when energy concerns are combined with other problems such as:

• Air leakage
• Failed insulated-glass seals
• Single-pane glass
• Poor operation
• Damaged frames
• Recurring condensation concerns
• Cold rooms near large windows
• Water infiltration

Do not replace a good window simply because a salesperson says every old window is wasting money.

Energy Savings Are Only Part of the Return

Replacement windows do not have to pay for themselves entirely through lower utility bills to provide value.

Homeowners may also benefit from:

• Improved winter comfort
• Warmer interior glass surfaces
• Reduced air leakage
• Better summer comfort
• Easier operation
• Easier cleaning
• Improved appearance
• Better ventilation
• Reduced maintenance
• Updated curb appeal

The utility bill is important, but it is not the only measurement of whether a window project was worthwhile.

Be Careful With “Your Windows Will Pay for Themselves” Claims

This is where homeowners should be skeptical.

Nobody can look at a window across your kitchen table and accurately guarantee exactly what your future utility bills will be.

Weather changes.

Energy prices change.

Families change thermostat settings and energy habits.

HVAC equipment ages.

Instead of asking for a dramatic savings promise, ask for measurable product information.

See and Feel the Glass Before You Buy It

Energy-efficient glass is difficult to understand from a brochure.

That is why we recommend visiting the Suburban Construction showroom at 3602 North Harrison Street in Davenport before deciding which glass package to purchase.

Our showroom features full-size replacement windows and an interactive “Feel the Difference” demonstration that allows homeowners to physically compare temperature transfer between standard glass and higher-performance window glass.

You can also compare:

• Double-pane glass
• Triple-pane glass
• Low-E glass packages
• Window frame construction
• Single-hung and double-hung windows
• Casement and awning windows
• Sliders
• Bay and bow windows
• Frame colors and grids

If energy efficiency is one of the main reasons you are replacing your windows, compare the glass before you compare the colors.

Plan a Visit to the Suburban Construction Showroom

A Better Way to Think About Replacement-Window Energy Savings

The Bottom Line: Will Replacement Windows Lower Your Energy Bills?

They can.

Replacing old, inefficient, poorly sealed windows with properly installed, higher-performance replacement windows can reduce energy loss through the windows.

But no reputable contractor should promise that every house will experience the same percentage reduction in its utility bills.

The greatest opportunity generally exists when you are starting with inefficient windows and replacing them with a substantially better glass system and a quality installation.

Do not buy replacement windows because someone promises a magical utility bill. Buy them because the product, glass package, installation, comfort improvement, warranty, and long-term value make sense for your home.