Windows and Doors
All windows and doors deserve more attention than they are generally afforded. This is particularly true of those in older houses. If not maintained over the years, major repair or replacement expense and difficulty can be incurred - especially in the case of old windows. The difficulty in repairing or even replacing old windows is often magnified either by the lack of repair parts or the discontinuance of the windows themselves.
There are five basic door styles found in most houses:
- Exterior Entrance Doors - Typically made of solid wood, metal, or fiberglass.
- Interior Doors - Individual room doors can be either hollow core or solid wood.
- Sliding Doors - Usually leading to a patio or deck, these doors are often make use of insulated glass for energy conservation.
- Garage Doors - Most often these are overhead doors installed on metal tracks. They can be manually or electrically operated.
- Storm/Screen Doors - Made of metal, wood, or fiberglass, these units are secondary doors serving a valuable seasonal function to conserve energy or keep out insects.
These doors are readily visible in most cases; however, the need for maintenance is not always as apparent. A coat of paint is the most often required maintenance for both interior and exterior doors. Doors will also require a periodic adjustment or planing of the edges to assure easy opening and closing, especially in older houses. Exterior doors should also be checked annually for suitable weatherstripping to minimize air infiltration or heat loss.
Storms and screens can become damaged during use as well as when in storage. Torn or dam-aged screening can be repaired or replaced, while cracked glass panels should be replaced for safety and to maintain their energy effectiveness. If the recurring breakage of glass panels occurs, an acrylic substitute (plexiglass) can be used.
Garage doors are the most neglected of all doors. If the doors are to last and function properly, they must be painted regularly and their mechanisms must be adjusted and lubricated periodically to provide for easy opening and closing. Garage doors also tend to suffer damage caused by careless driving.
Aside from window storm and screen windows, there are six basic styles found in residential construction. The different styles are:
- Double-Hung - This is the most common type window. It consists of two sashes which slide up and down in slots in the window frame. Old units had ropes and chains or cords; newer units use a friction fit to hold open the windows. If the friction fit can no longer be adjusted to give a tight hold, this mechanism or track must be replaced. are used in windows, doors, and skylights. An insulated glass unit consists of two or three panels of glass separated by an air space. A double-glazed unit has two glass panes; a triple glazed unit has three glass panels and two air spaces.
- Sliders - The sashes move side to side along sill tracks. There is a wide quality range on sliders. In some cases, only one sash is movable.
- Casement - The sash is hinged at the top and bottom corners to allow for the outward motion. The window can be operated by a push bar or a crank. These units tend to warp with age or weather exposure. Also, adding storms and screens is more difficult with casement windows.
- Awning - This type window is hinged along the top and opens out at an angle resembling an “awning.” Interior opening mechanisms typically allow for storm/screen placement on the inside window frame.
- Jalousie - Narrow, horizontal glass panels or slats make up a jalousie window. The slats are controlled by a crank mechanism either collectively or in groups. Jalousie windows are not very infiltration resistant or energy efficient.
- Hinged - This type of window can be hinged at the top or the bottom. Often found in basements, hinged windows are opened by a handle or manually.
Insulated-glass units (IGU), also referred to as thermal glass, thermal panes, double or triple glazed units, or sealed units, are used in windows, doors, and skylights. An insulated glass unit consists of two or three panels of glass separated by an air space. A double-glazed unit has two glass panes; a triple glazed unit has three glass panels and two air spaces.
Glass itself is a poor insulator. By providing a dry, dead air space between the panes of glass the rate of heat transfer through the glass can be reduced to less than half the heat loss or gain than through a single-pane unit. Just as significant as the increased insulating value in cold weather is the energy savings due to reduced heat gain during the air conditioning season. In addition, using insulated glass increases occupant comfort by cutting down on convection cooling - the drafty feel you get when standing near a window on a cold day.
To further increase the insulating value of IGUs, manufacturers add reflective coatings or use high-emittance glass to reflect radiant heat and slow heat transfer through the glass itself. Special gases such as argon and krypton often are used in place of air to further reduce heat transfer.
While ICUs provide improved comfort and efficiency, they are subject to breaks in the airtight seal around the perimeter of the glass assembly. This condition can occur due to manufacturing defects, improper installation or maintenance, or simply normal aging. Manufacturers generally provide 15 to 20 year warranties, although properly maintained, better quality units can last for many years beyond the warranty period.
The initial loss of the seal is usually not detectable, but can eventually result in condensation or fogging between the panes, which can vary seasonally and increase with time. The energy efficiency of the units is also affected to a degree, but the heat transfer through the unit will still be less than single glass. While there are several proprietary methods for restoring the seals in place; these may be feasible only in some cases; however, replacement of the effected units is the normal approach.