A Brief Guide to Choosing Energy-Efficient Windows for Your Home

According to the Department of Energy, an estimated 10-25% of household heating and cooling bills are lost through window leaks. Choosing to install the right windows will help you cut back on these leaks and reduce utility costs.

For many energy-conscious homeowners, installing energy-efficient windows is an excellent investment. Energy-efficient windows are designed to provide all the benefits of traditional windows but with the bonus of helping you save more energy.

If saving energy and money is the focus of your next window replacement project in Maryland, this brief guide will help you plan for your energy-efficient windows.

What are Energy Efficient Windows? 

Energy-efficient windows look like your average window, but they are specifically designed to prevent hot and cold air from leaking out of your home. They improve insulation, lower your energy usage, and reduce your utility bills.

Like most windows, energy-efficient versions are made of glass, but their special coating makes them unique. This coating reflects UV rays, preventing the latter from entering and warming your home.

Energy-efficient windows usually have two or three panes of glass that reduce UV transmission further. Some designs also have spaces between panes filled with gasses like Krypton and Argon, which thwart energy transfer.

In addition, energy-efficient windows have long-lasting, high-efficiency sashes that stop air from leaking out of the house.

Factors that Influence Energy Efficiency

Several factors affect the efficiency and quality of an energy-efficient window. When you’re looking for energy-efficient replacement windows, keep the following factors in mind:

1. Window Frames

The type and condition of a window frame affect the overall thermal performance of the window. Old or damaged frames usually have air leaks that may affect the temperature of the house.

For example, if hot air frequently leaks through a damaged window frame during winter, your heater would have to work overtime to keep up with the loss in temperature. It will eventually raise your energy usage and bills.

While every energy-efficient window has specialized frames, the material you get distinguishes the advantages (or disadvantages) you’ll get.  Here are some of the popular window frame materials:

  • Aluminum and Other Metals: This type of frame is light, durable, and very recyclable. Aluminum frames are efficiently designed, making them an excellent choice for aesthetic purposes. Unfortunately, metal is a poor insulator because it is a conductor of heat. When exposed to the sun or hot temperature outside, it can easily absorb the heat.
  • Wood: Wooden frames are exceptional natural insulators and come in various aesthetically pleasing designs but require constant maintenance to prevent rotting. Wood also tends to expand and contract depending on the weather, potentially creating gaps that lead to leakage.
  • Fiberglass: This is one of the most popular window frames available. They are structurally superior to most other frames. Fiberglass frames are considered stable and durable with air cavities that can accommodate more insulation.
  • Vinyl: This type of frame is generally made of unplasticized polyvinyl chloride (UPVC). Apart from their durability, vinyl frames prevent heat and sunlight from breaking the material down slowly. However, they do lose their color and shine after a while. Vinyl frames are also the most affordable among the materials.
  • Composite: Composite material combines wood products like laminated strand lumber and several polymer plastics. This mixture makes composite frames stable. Like wood, composite frames are an excellent insulator, and the plastics provide strong resistance from decay.

2. Energy-Saving Glass

The type, style, and thickness of glass contribute a lot to your window’s energy efficiency.  That’s because the glass allows solar rays to enter or leave your home. The glass’s heat conductivity also has an impact on energy efficiency.


When it comes to energy-efficient windows, these are the common glass types and configurations available:

  • Laminated: This type of glass is made from two or more panes of glass with a layer of plastic called polyvinyl butyral (PVB). Laminated glass is considered a safety glass because of its ability to hold together when shattered. It also has decent energy-saving capabilities.
  • Low-Emissivity (Hard Coat): Low-emissivity or Low-E is a glass coating that reflects light from the sun and prevents heat from leaving the room. Hard coat is a very robust variation of the Low-E coating. Its durable design allows it to be used as a single pane of glass (single glaze).
  • Low-Emissivity (Soft Coat): This Low-E glass variation is considered the most energy-efficient. However, its design makes it very vulnerable to damage. A simple scratch from your finger can remove the soft coating. Low-E soft coats are generally used as part of a double-glaze unit.
  • Solar Window Film: A solar window film works the same way as a car’s window tint. It allows just the right amount of light in, reduces glare, minimizes heat, and increases solar reflectivity. Solar window films also come in a wide variety of colors.
  • Single Glazed Configuration: This type of configuration only uses one layer of glass or one pane inside the window. It can accommodate many glass types. Single glazed windows can be found in almost any standard home.
  • Double Glazed Configuration: This type of configuration uses two or more glass layers separated by an air gap. This air gap is filled with gasses like Argon or Krypton and acts as an insulating barrier. It has significantly lower conductive properties, making it a very energy-efficient option.

3. Window Types According to Operation

Apart from the different kinds of frame material and glass, the manner of operation contributes to a window’s energy efficiency. Here are some window operating types worth considering:

  • Awning: This window is hinged at the top and opens outward. It has lower air leakage because the sash closes by pressing against the frame.
  • Sliding (Single or Double): The sashes of this window slide horizontally. When it comes to energy efficiency, sliding windows have higher air leakage rates compared to other types of windows,
  • Hopper: The hinges of this window are at the bottom, and they open inwards. Similar to awning windows, this design has lower air leaks and higher energy efficiency.
  • Fixed: The panes of fixed windows cannot be opened. When properly installed, they can be very energy-efficient and airtight. However, keep in mind that fixed windows are not suitable for rooms that require proper ventilation.
  • Casement: This window is hinged at the sides. Like the hopper and awning types, the casement window sashes close by pressing against the frame, reducing the chances of air leaks.
  • Hung (Single or Double): This type of window’s sashes slide vertically for both single or double-hung versions. Just like sliding windows, hung windows are very prone to air leakage and are generally not energy-efficient.

Energy Efficiency Labels You Should Look Out For

When shopping for energy-efficient windows, it’s important to look for their energy rating and certifications. This information is generally found on stickers bearing the ENERGY STAR and National Fenestration Rating Council (NFRC) stickers.


ENERGY STAR is an official government program that provides energy-efficiency certifications for windows, doors, and home appliances. Every ENERGY STAR sticker includes an official rating and information about how much money or energy you’ll be saving while using the product.

Some ratings can also tell you which state or region the window is certified to do better. The sticker provides specific energy performance ratings to look for in your climate.

2. NFRC Performance Label

Unlike the ENERGY STAR sticker, The National Fenestration Rating Council (NFRC) label provides more specific details regarding your prospective window’s energy performance so you can easily compare it to other products.

The NFRC window rating is also a great way to determine its “whole unit” energy performance and not just the quality of the glass. Door and window manufacturers have to pass the strict NFRC requirements before earning the label.

How Much Does Energy Efficient Windows Cost?

The average cost of an energy-efficient window is $555. However, the actual cost will still depend on the brand, frame, window type, and specific energy feature it offers.

For example, an energy-efficient window with an ENERGY STAR rating can go as low as $325 for a single-hung vinyl window. Meanwhile, a large casement window with wooden framing can cost you around $825, including installation.

The number of panes the windows have can also affect the overall cost. Here are some estimated prices for double and triple pane windows:

  • Double Pane (Vinyl): $450 to $650
  • Double Pane (Wood) $800 to $1,050
  • Triple Pane (Vinyl): $550 to $850
  • Triple Pane (Wood): $900 to $1,250

You can expect to pay around $50 to $100 per window installation for new construction.

Bottom Line

An adequately installed energy-efficient window can help you save $126 to $465 a year by simply replacing old single-pane windows. For homeowners looking for ways to save money, getting energy-efficient windows can be an excellent long-term investment.

This guide should help make your search for the right energy-efficient window easier. Of course, it’s best to reach out to your trusted contractor to help you determine the perfect energy-efficient window for your home.

G.H. Clark Contractors, Inc. offers reliable window replacement and installation services in Maryland. If you plan on having your windows replaced, contact us today to discuss your project and get a free estimate.

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