House Energy Site

Improving window energy efficiency

Windows provide light, solar heat gains, ventilation and views, but that may come at a high price: windows are a common cause of heat loss, overheating, glare and air leakage.

Windows Energy Improvement

Windows are responsible for high air conditioning costs in hot climates; and for huge energy loss and energy costs in cold climates.

To prevent it, choose the right type of windows, taking into consideration your climate.

windows and climate change

infographic house energyMore Animated infographics that you may use freely:

See a list here: List of Energy & Infographics


In New Construction, Pay Attention To the Size, Type and Placement of Your Windows

In new construction consider high energy-efficient windows, but also their size, according to the side of the house (N-S-E-W) and your climate.

Window sizing

Why So Many People Feel Disappointed With Their New Windows

Windows are not all equal. Having triple or double-pane windows, with gas between the panes and low e-coatings, doesn't necessarily guarantee much of anything.

You have to take into consideration your climate and the energy coefficients of the windows. And you may have to improve the insulation of your walls, attic and floors.

Energy efficient windows in poorly insulated and sealed homes will not reduce significantly your energy bills, or enhance your comfort.

New Windows Should Be Properly Chosen; Climate Matters

Prefer high-performace windows, but do not forget the basics about overall insulation and airtightness. There are issues about the type of glass, frame, edge spacers, or type of opening that should be properly addressed.

Typically, Energy Star windows worth the price, but there are better standards.

The best Windows for cold, hot and mix climates
New Smart Glazing Windows

Windows clipFiberglass, vinyl, wood, clad, composite and aluminum windows

Fiberglass and vinyl windows are two excellent alternatives to wood or to aluminum windows..

In very general terms, windows with foam-filled fiberglass frames perform better, with foam-filled vinyl windows coming second, followed by wood-frame windows.

Aluminum vs Vinyl vs Fiberglass vs Wood vs Clad window Frames and Sashes

Protect your Windows

Windows must be shaded during the summer, using overhangs, vegetation, devices; and they should be protected from the cold winds through landscaping or by other means.

Landscaping for Energy Efficiency
Cooling with Shade Guide for Energy Efficiency

What about the Use of Windows and Dark High-Mass Floors to Capture and Store Solar Heat Gains?

It's part of passive solar design, in cold climates: properly sized windows on the sunny side of the house, working in conjunction with dark high-mass floors or interior walls to capture and to store solar heat, during the cold weather period of the year.

Clerestory windows are often part of these strategies.

Unfortunately, these strategies are not easy to implement. Their effectiveness depends a lot on design and climate issues.

Passive Solar Design and Passive Solar Houses
Thermal Mass Principles
Thermal Mass Guide
Clerestory Windows for Ventilation and Passive Solar Buildings

Window Films Can Reduce Summer Energy Bills by Hundreds of Dollars

Spectrally-selective window films can be a very effective and low-priced choice to reduce cooling bills, in homes with poor quality windows.

See: Window films for energy savings

Casement windowCasement Windows for ventilation and Airtightness

If you're looking for the best window option for ventilation and to block air leakage, than casement windows is probably the best choice.

Types of Window Operation
Casement Windows Energy Efficiency
Sliding Windows Energy Efficiency


Natural Ventilation and Cooling With Windows

Breezes can be found almost everywhere, even if for short periods of time; and windows can bring them into our homes for free, in hot climates.

See: Cooling with Natural Ventilation

Weatherstripping and Caulking your Windows

Windows Caulking
Weather-stripping your windows
Window weatherstrip materials

Foggy Windows?

Many homeowners often feel disappointed with new windows.

See: Water Condensation & Windows

How Good are Storm Windows?

Storm windows can be very effective in cold climates, in homes with low-energy efficient windows. Exterior storm windows can reduce energy loss through windows up to 50%, if equipped with low-E glass.

Storm Windows Pros, Cons and Alternatives

Window Costs and Payback

According to the National Association of Home Builders new windows cost about $6.000 on average, that is, about 3,3% of the overall cost of the house.

See: Energy-efficient Windows: Costs and Payback

See also:
Top Double and Triple Pane Window Manufacturers
Daylighting & Windows
Online Resources on Residential Windows


101 Ideas

About to build a new home?

Read our book (Print and Kindle ebook versions);
Save thousands of dollars;
Avoid costly mistakes and pitfalls.

HOUSE ENERGY BOOK, available on Amazon:
101 Ideas To Improve Your New Home: Home design, energy efficiency and green construction.


Videos on Windows

Using Windows for Energy Efficiency
Replacement vs. Improving Windows
Window Selection Criteria for Energy Efficiency





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