Storm windows, screens, and storm doors
Windows are a major source of heat loss. On a per-square-foot basis, more heat is lost through windows than any other area. In fact, the heat lost through a single-pane window is approximately fourteen times greater than that lost through a well-insulated wall of comparable size. However, with storm windows, the heat loss can be reduced by about 50 percent. There are three basic types of storm windows: storm sashes, storm panels, and combination units.
A storm sash is a removable sash, usually made of wood, containing a fixed-pane window. The storm sash fits over the window on the outside or inside, depending on how the window opens. Storm sashes are most commonly found on the outside of older double-hung windows. They are not desirable for year-round use because they cannot be opened to admit breezes during the warmer months. Storm windows are generally taken off in early spring and reinstalled in late fall, a task that can be somewhat awkward and time-consuming.
A storm panel looks like a storm sash, but it is usually mounted in a narrow metal frame and is attached to the movable window sash rather than being fitted over the entire window opening. Since storm panels are attached directly to the movable sash, they do not interfere with the operation of the window and need not be removed during the warmer months.
Combination units refer to storm and screen sashes combined in a single frame. The unit is mounted over the outside of the window and is therefore effective in reducing air infiltration around the window joints in addition to reducing heat loss. Combination storm and screen windows are available in two- and three-track units. With two-track units, the outside track contains the storm sash in the upper half and a screen sash in the lower half. With the screen in position, the upper storm sash cannot move. The inside track contains the lower storm sash, which can slide up and down. In a triple-track unit, there is a separate track for each of the two storm panes and for the screen. Combination storm and screen units are generally found on double-hung and horizontal sliding windows. Since these units do not interfere with the operation of the movable sash and can also be opened to provide ventilation, they are not normally removed once installed.
Combination units are available in aluminum, steel, or solid vinyl. The aluminum frame with a baked enamel finish looks like a vinyl frame. You can tell the difference by looking at an edge or joint. The aluminum edge will have a silvery color; the vinyl edge will be the same color as the frame. Over the years, many aluminum frames with a mill finish (plain aluminum) show the effects of weathering, such as pitting, corrosion, and a degraded appearance. An anodized or baked enamel finish will offer greater protection against weathering. Combination storm and screen windows made of steel have a tendency to rust and require periodic painting.
Most window screens for residential structures are either mounted on a wood sash or rimmed with a metal or plastic frame. The wood-framed screen is usually used in conjunction with a storm sash; the metal- or plastic-framed screen is used in the combination storm and screen unit. Metal- or plastic-framed screens are also used for casement and awning-type windows. However, for these windows, the screen must be equipped with panels that provide access to the cranks or push bars.
Another type of screen (not very common) is the roll-up screen. This screen is mounted on the inside of the window and is similar in operation to a roll-up shade. When the screen is not being used, it can be rolled up and hidden from view. The sides of the screen move in metal tracks to prevent insects from flying in around the edges. As the screen ages, the joint between the screen and the track tends to open and become less effective.
In colder climates, unless the exterior doors are insulated, they are often used with storm doors to reduce heat loss and cold-air infiltration around the joints. Storm doors are generally lightly constructed wood or metal stile-and-rail-type–doors with a glass-panel insert. On many of these doors, the glass insert is interchangeable with a screen panel so that they can function as both storm and screen doors. Because storm doors are constantly being opened, they are not as effective as storm windows in reducing heat loss. Nevertheless, they are effective from an overall energy-conservation point of view.
When inspecting the house, look for storm windows. If you do not see any or the inspection is being performed during warmer weather when storm sashes are normally not installed, ask the owner whether the house has storm sashes for all the fixed and movable windows. If no storm windows or only a few are available, record the fact on your worksheet. Installing a complete set of storm windows can be quite costly.
Storm windows should be inspected for cracked, broken, and missing panes. When the storm sash is wood, check for cracked, broken, and rotting sections. On combination units, look specifically at the corner joints. These joints should be tight so that no cold air leaks into the unit. Check the overall condition of the frames. Are any sections loose, broken, rusted, or corroded? Are any of the panes loose in the sash? Look for torn sections and holes. In metal-and plastic-rimmed screens, the screening is normally held in position by a spline that has been forced into a groove around the frame. Periodically, I find splines hanging loose within the frame of the combination unit. Loose splines are an indication that the joints in the associated screens must be resecured.
Storm doors should be checked for ease of operation and overall condition. Are sections cracked, broken, loose, rotted, or corroded? Is the glass panel loose, cracked, broken, or missing? If you find any problems with the storm windows, screens, or storm doors, record them on your worksheet as a reminder for later correction.