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TECHNOLOGY AND YOU

Interior storm windows are low-cost alternative

Q: Dear Jim: My old windows are not worn enough to replace, but they are drafty, sweat during cold spells and cause the furniture to fade. I saw some low-cost, reusable interior storm window kits. Are they worthwhile?

A: Reusable rigid interior storm window kits are an excellent low-cost energy-efficient alternative to replacement windows if your present windows are still in reasonably good condition. Many are designed for simple do-it-yourself installation, and others can be dealer installed. With proper care, these storms will still look like new after ten years or more.

In addition to windows, do not forget any skylights that you have. Skylights, particularly older ones, can lose a substantial amount of heat and cause fading of furniture and carpeting. I installed a magnetic storm window kit in my own living room under a new super-efficient double-pane skylight.

Unless you use natural ventilation in the summer, leave the interior storm window kits up year-round for the most savings, outdoor noise reduction and comfort. With the narrow plastic frames, the storm windows are barely noticeable. The frames are available in several colors or you can paint them to match your walls. If you have natural wood window frames, select a kit with wood-grained frames.

Most storm window kits use lightweight clear acrylic because it insulates better than glass, and it is safe and easy to work with. For the lowest cost, you can often mail order the frame kit for your window or skylight and then buy standard acrylic sheet at any local home center store.

Acrylic is a crystal clear plastic and does yellow over time like other plastics. It is very impact resistant (safe around children) and naturally blocks nearly all the sun's fading ultraviolet (UV) rays. For the greatest strength, choose polycarbonate ("bulletproof glass") plastic. It is more expensive and will yellow slightly over time.

If you have a window condensation problem in the winter, interior storm window kits can help. You must first paint the inside surfaces of the window opening with a sealer type of paint and then paint it with your regular wall paint, if you like. This blocks indoor moisture from passing through the drywall and getting between the storm and primary window.

There are many designs of interior storm windows. Ones that use quick-to-install magnetic seals are most common. To make them less noticeable, they can be mounted directly against the primary window frame (creates a small dead air space) or inside the window opening on an L-channel.

Another option is to mount them over the entire window opening, overlapping on to the wall by an inch or so. This is the easiest installation method, but the deep air space between the storm and the primary window will allow wasteful air currents to develop between them.

A magnetic strip, usually about one-half inch wide, is embedded in the rigid vinyl storm window frame. A thin, self-adhesive steel strip is attached with adhesive to the wall or window frame. The powerful magnet holds the storm window snugly against the strip for an airtight seal.

If your old window frames are warped or wavy, choose a design that uses flexible bellows between the window frame and the magnetic strip (South Sun Energy Conservation "Winsulator"), This functions just like your flexible refrigerator door magnetic seal. It also helps to absorb impacts from your children.

Other attachment options are clips and hook-and-loop strips. Clips are often used on very large storm windows. Hook-and-loop strips hold very tightly and are easy to install and remove each year. Pipe Perfect Windows uses a simple design with foam tubing to form a snug, easy-to-install fit.

For very drafty old windows, select a kit with a secondary seal in addition to the primary attachment seal. If you have slider or double-hung windows, select a split kit (Magnetite "EZ Divider") that allows half of the window to be opened.

There are several kit purchasing options. The lowest-cost option is to buy a do-it-yourself frame-only kit. You cut the vinyl frame sections yourself and purchase the clear acrylic wherever you find the lowest price. Other companies only sell complete kits through professional installers, but offer longer warranties.

Write for (or instant download - www.dulley.com) Utility Bills Update No. 728 - buyer's guide of the 10 best interior storm window kits, frame/window materials, attachment methods, installation instructions and specs. Please include $3.00 and a business-size self-addressed stamped envelope. Mail to: Jim Dulley, Illinois Country Living, P.O. Box 3787, Springfield, IL 62708.

James Dulley is a mechanical engineer who writes on a wide variety of energy and utility topics. His column appears in a large number of daily newspapers.

Copyright 1999 James Dulley

18 ILLINOIS COUNTRY LIVING JANUARY 2000