Low-E window film can increase comfort, efficiency
Q. My home’s single-pane windows are still good, but a lot of heat comes in during the summer, and it’s chilly near them during the winter. Would installing one of the newer year-round or heat-control window films help much?
A. Installing window film can be an effective way to improve the efficiency of your window glass. The newer window films are neither highly reflective nor darkly tinted, so your house will not end up looking like an office building that has mirrors for windows. Some window films are barely perceptible.
The newer energy-control window films use a technology similar to the super-efficient glass used for new replacement windows. A low-emissivity (low-E) coating, which is a several-atom thickness of metal, is applied to the film. Visible light can easily pass through the coating, but it blocks heat energy.
The amount of tint applied to the window film also affects the amount of heat from the sun that can pass through the glass. With the low-E coating on a dark film, a high percentage of heat and glare will be blocked. This type of sun-control film is typically used in hot climates.
For homeowners who wish to save energy year-round, a very lightly tinted window film is best. This type of film barely alters the view outdoors, but it blocks some summer heat, in addition to preventing heat loss during the winter. Also, during the winter, the lightly tinted films still allow some free passive solar heat to come in through the window and reduces that chilly feeling you sometimes get near a window.
A secondary benefit of installing window film is that it blocks the majority of the sun’s UV (ultraviolet) rays, which fade curtains, furniture and carpeting. Many homeowners install the nearly clear window film solely for this purpose. Yet another benefit of window film is that it reduces the possibility of glass shattering from an impact. This is a safety plus around children.
If you have double-pane windows, check with your window manufacturer before installing window film. Dark films can warm the glass, which may affect the airtight seal between the panes. The nearly-clear films do not cause much heat buildup, but you should still check to make sure about the glass warranty.
Do-it-yourself window-film kits, including a squeegee and application tools, for various-size windows are available at most home-center stores. The film is also available on large rolls
"If you have doublepane windows, check with your window manufacturer before installing window film."
so you can buy as much as you need. For summer heat control, a home’s west- and south-facing windows are most important to cover. It can also be effective to place awnings over windows on the home’s south side.
Installing window film yourself is not difficult. There is a water-activated adhesive on the window film. Make sure the glass is very clean and that the film is thoroughly wet. Apply the film, and carefully run the squeegee over it to force out all the bubbles to the edges.
The following companies offer energy-saving window films: 3M (www.3m.com, 866-4998857), Gila Films (www.gilafilms.com, 800-528-4481), Madico (www.madico.com, 800-456-4331), Plastic-View International (www.pvifilm.com, 800-4686301) and Solar Gard (www.solargard.com, 877-273-4364).
Q. When I build an addition for my home, I plan to use rigid-foam-insulated sheathing on the outside of the wall studs. Will it harm the efficiency to use extra nails and fasteners for a stronger wall?
A. Adding more nails and metal fasteners than recommended by the manufacturer will not produce a better wall. It is usually best to follow the foam
manufacturer’s instructions or buildingcode requirements.
Any metal fasteners will decrease the effectiveness of rigid foam insulation. Using just the recommended number of nails and fasteners (on 8-inch centers) can reduce the overall insulation value by 5 percent or more.
Send inquiries to James Dulley, Arkansas Democrat-Gazette, 6906 Royalgreen Drive, Cincinnati, OH 45244 or visit www.dulley.com.