Ways to Reduce Energy Loss with Windows

The U.S. Department of Energy estimates that 30% of a home’s heating energy is lost through windows while 76% of sunlight that falls on standard, double pane windows turns into heat during the summer.

1. Replace drafty windows—Replacing old, drafty windows with energy efficient windows can help you reduce your heating and cooling costs.

2. Check for window drafts by holding your hand near the top or bottom of the window sash where it meets the frame. If you feel a breeze, you have a draft. Another way to check for drafts is to hold a candle near a window, and if the flame flickers, it’s an indicator of a draft. Remember to use caution with candles to prevent fires. 

3. Get windows with double glazing—Marvin Replacement windows have two panes with Low E coatings

   Low E

   E stands for emissivity, which is a material’s ability to radiate energy. The number following the “E” indicate the number of metallic layers. Marvin Replacement windows and doors have four choices of Low E coatings. The coatings are thin metallic layers designed to reflect heat. Marvin Replacement Low E options are: Low E1, Low E2, Low E3, and Low E3/ERS. Low E1 glass glazing works best in colder climates because it allows more heat in to warm a room while blocking heat loss. Low E2 works well in moderate climates because it can help retain heat in winter and reject heat in the summer. It blocks 84% of the sun’s UV rays to reduce color fading. Our Low E3 and our Low E3/ERS glazing work well in warmer climates because they will block solar heat. A Low E3 window will block up to 95% of UV rays.

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   . Argon

   Argon

   A colorless and odorless gas used to fill the airspace between insulating Low E glass. The addition of argon greatly increases the insulating performance of Low E glass.

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   gas sits between the panes and acts as an insulator while the coatings can prevent heat loss or keep homes cool. 

Ways to Reduce Heat Loss  

1. Use curtains—Thick curtains with thermal linings can help reduce the loss of home heating because it creates a barrier between your window and the rest of your home. 

2. Open curtains or blinds on sunny days. 

3. Close blinds or curtains at sunset to retain heat. 

4. Seal windows by placing plastic film over windows—Find a plastic film kit at a home improvement store. It’ll include double-sided tape that you’ll place along the frame. Adhere the plastic film to the tape, trim the film to fit and use a blow dryer to create a seal to prevent heat loss.  

5. Close unused rooms—If you can close the door to unused rooms, you can reduce cold airflow from coming out of the room and prevent hot air from entering the room.  

6. Insulated cellular shades—Insulated cellular shades look similar to blinds, but they usually have four sides and an air pocket in the middle to trap air and act as insulators. The Department of Energy estimates insulated cellular shades can reduce heat loss through windows by 40% or more. During warmer months, they can reduce unwanted solar heat by 60%. 

7. Exterior shutters and shades—Shutters and exterior shades can help reduce the amount of sunlight pouring through a window. 

8. Awnings—Awnings can extend over windows and cast a shadow to decrease the impact of sunlight entering a home. The Department of Energy estimates awnings can reduce solar heat gain the summer by up to 65% on south-facing windows and 77% on west-facing windows. Awnings work well during warmer months, but can increase energy use in the cooler months.  

   *Savings reflects installing ENERGY STAR certified products compared to non-certified when replacing single pane windows based on the average savings among homes in modeled cities. Actual savings will vary by product type, location, method of installation, individual home characteristics, local climate and conditions, utility rates and other factors.