Dear Jim: Our house has its original single-pane windows, and we always feel chilly near them. I got quotes on having them replaced, but I can’t afford it now. What can I do in the meantime to improve the efficiency of the old windows? — Pete N.
Dear Pete: I’m not surprised to hear you feel chilly near old single-pane windows. The most significant heat loss and chilly feeling occurs on a clear winter night. The R-value — a higher-the-better number that shows the ability of insulation to resist the transfer of heat — of a single pane of glass is only R-1, as compared to an insulated wall at R-20.
There are many things you can do on a limited budget to improve the year-round efficiency of your windows. Before you attempt to make any improvements, though, first check the caulking and weather stripping on the windows and ensure the framing is not deteriorated. If you find subpar conditions, fix them before you attempt any improvements, or your hard work won’t be worth much.
Adding storm windows, either interior or exterior, can more than double the energy efficiency of your existing windows. Custom-made, multi-track storm windows can cost almost as much as totally new windows, so make your own using clear acrylic sheets. Another advantage of using acrylic instead of glass is that acrylic blocks most of the sun’s fading ultraviolet rays.
Exterior storm windows can be made with 1-by-2-inch lumber, acrylic sheets and foam weather stripping. If you size them to fit inside the wall opening and paint them to match your existing window frames, they will look like part of your windows. The compressible foam weather stripping should hold them in place in the opening. Push them in as far as possible to minimize the air gap.
To install interior storm windows, use a kit with magnetic seals. The magnetic section of the seal attaches to the acrylic sheet with an adhesive backing, and the steel strip attaches to the window frame. This allows you to easily remove them during summer for ventilation, but if you use air conditioning most of the summer, just leave them up year-round.
Another option is to install insulating window shades or curtains to increase the overall insulation level of the window opening and block radiant heat loss. Something as simple as a pull-down pleated shade can help quite a bit. Even closing Venetian blinds blocks your skin’s exposure to the cold outdoors.
Some of the most efficient window shades can add R-6 insulation to your windows. These are multilayer roll-up shades with a heat-reflecting, airproof inner film layer to greatly reduce radiant heat loss (or gain during summer).
The newest energy-saving permanent window films are also effective for reducing wintertime heat loss. These films have just a very slight tint so they can’t be detected and use the same type of microscopically thin, low-emissivity metallic coating as expensive replacement windows. Simple vinyl static-cling film will also help a bit. But before installing anything on double-pane windows, check the window manufacturer’s warranty regarding film application.
A final option is to install a tilt-in double-pane, sash-only replacement kit. If your existing frames are in good condition, this will convert your old windows into very efficient ones. This option also provides the convenience of tilt-in sashes for the ease of cleaning both sides of the window glass from indoors.
Have a question for Jim?
Send inquiries to James Dulley, The Tennessee Magazine, 6906 Royalgreen Drive, Cincinnati, OH 45244, or visit www.dulley.com.