Boost window performance without the high expense of complete replacement.
Windows play a unique role in our houses. They provide views to the outdoors, introduce natural light, deliver passive solar heat, and provide natural ventilation.
But they are expensive. A top-quality window can cost $50 per square foot or more—$600 for an average-size (3- by 4-foot) window. A state-of-the-art, triple-glazed replacement from Germany can cost more than $1,000. Count up the old windows in your home, and you’ll quickly see that replacement can be expensive, often costing thousands—or tens of thousands—of dollars.
With 130 million houses, mobile homes, and apartments in the United States—and a majority of them with poorly performing windows—it’s unrealistic to think about replacing most of them. This article looks at alternatives to replacing windows while still significantly boosting their energy performance.
There are affordable options for reducing heat loss in the winter and reducing unwanted heat gain in the summer and in warmer climates year-round. Some treatments can do both. And if implemented well, such window treatments or attachments can enhance a home’s appearance.
Transparent films can be applied to windows to reduce unwanted solar heat gain and reduce heat loss. These plastic films, which are typically made of polyester, are usually applied directly to the interior glass surface, though some products are for the exterior. They are most commonly installed in southern climates to reduce solar heat gain, though some newer, low-e films are more transparent and help reduce heat loss.
While there are window-film kits for do-it-yourselfers available at home centers, the best installations are done professionally by trained installers. Most films are 2 to 7 mils (0.002 to 0.007 inches) thick and come in 36- to 72-inch-wide rolls.
Applied window films are fairly permanent modifications. They cannot be adjusted like most other window treatments, and they are difficult to remove.
The energy performance of applied films is certified by the National Fenestration Rating Council (NFRC). In fact, this is the only window treatment with NFRC certification. Ratings are provided for U-factor (a measure of the heat loss through windows); solar heat gain coefficient (a measure of how much solar heat enters through the window—which can be desirable or undesirable); and visible transmittance (a measure of how significantly films affect visibility through the windows). Tinted films, for example, will dramatically reduce solar heat gain and visible transmittance, but have little impact on U-factor, while newer low-e films may reduce the U-factor (lower U-factor means less heat loss) with minimal impact on the visible transmittance.
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I have customers who are always asking about window films when they come for a vehicle wrapping. It could be something to really look into since it seems like there's a market for this sort of thing for car windows in addition to residential windows don't you think? It'd be nice to be able to provide a one stop service for people looking to do up their cars in my opinion! Maybe it's time to start researching how to incorporate this into our business model!
Great post!!!
Thank you for sharing ideas.
Quick overnight response from these folks to my email inquiry about vertical blind slats.
A very interesting product indeed, the videos on their website are informative. Just requested a quote for their vertical blind slats.
While living in Maryland I covered half my windows in each room with aluminum screen frames covered with clear heat shrink. The rest of the windows were covered with 1" styrofoam panels. Both installed inside. Really reduced heating costs even tho my windows were all double glazed with low E treatment. Easy to store between use.
The 1" styrofoam will reduce heat gain on a sunny day, and yes reduce heat loss at night, or in the mornings/evening when there is no sunlight coming into the window. At the same time, not having daylighting can increase the use of interior lights and that can increase the electric bill.
So some sort of night time only shutters, or styrofoam installed each afternoon, and removed during daylight heating times would improve the heat gain while reducing heat loss.
My sister's home in Phoenix AZ has screens on both the opening and fixed windows. This reduces sunlight hitting the glass, and thus less heat gain to the windows. Air can still circulate to remove any built up heat between the screen and glass. She would benefit from styrofoam covering the windows, yet it would give a "Cave" like feeling too. She would rather have more daylight and higher A/C bill.
The electric shades also look very promising. I know people who have them installed on motorhomes, and there is a wind sensor that brings them in at 15 MPH winds to avoid damage to the awnings.
Thank you for this informative article! There are so many other options than window replacements and I hate seeing those beautiful old windows go into landfills. Alternatives are more eco-friendly and can be just as efficient as a replacement. Save those historic windows!
One option which is not mentioned is the use of bubble wrap , this of cause is only suitable for out buildings or where the need for improved performance out weighs aesthetics . whilst it can be stuck to glass with water I have found that fixing to the frame is better as this cuts down on air leakage . The bubble wrap can be ripped/cut in case of emergency exit .