Windows can be used to provide fresh air and remove excess humidity and odours. But be careful. It's hard to control windows as ventilators, and it is easy to let in too much cold air.
Trim Areas
Seal areas of air leakage around all trim. In some cases, this can be done easily by sealing all the joints with a flexible caulk that is clear or paintable and of a matching colour. A more effective solution for leaky or poorly fitted trim is to carefully remove the trim and seal behind it. Insulate wide cracks with a foam backer rod and seal them with caulking, polyurethane foam, or other suitable material.
If baseboards are removed, you might also be able to caulk between the wall finish and the bottom wall plates and between the plates and the floor.
If you are rebuilding the existing wall, seal all cracks around window frames with polyurethane foam sealant or stuff the gap with insulation and caulk.
If installing a new wall, you must frame the windows. Seal the point where basement window frames adjoin the wall with caulking compound, and then insulate.
Glass Panes
The seal between glass and its wood frame should be tight. Check the glazing carefully and be certain that all the seals are intact, with no cracks or missing sections. If not, repair them with putty or glazing compound. Putty usually costs less, but tends to dry out and crack faster, unless you put linseed oil on the wood first. Glazing compound, on the other hand, lasts longer and stays semi-soft and usable for longer. Remove the old putty and apply the new materials with a putty knife. Be sure to press it firmly into the space for a good seal.
Windows that are Never Opened
If you don't need a window for ventilation or as a possible emergency escape route, seal it by caulking rather than weatherstripping. Caulking is likely to be quicker, cheaper, and more effective. First, close the window sash onto a bead of caulk. Pry loose the vertical stops on each side of the window with a putty knife. Start prying at the centre, and work towards the top and bottom. (If you are careful not to bend the nails, replacement will be easy.) With the stops removed, caulk between the sash and the window casing. The caulk can then be concealed by the stops. Alternatively, install a special strippable caulk that can be removed when you want to operate the window again.
Window Coverings
Shutters, shades, and awnings can be used to keep the sun out. Window insulation can be used in the winter to provide extra insulation for improved comfort and energy savings. For window coverings to work properly, they must fit tightly around the window frame. Air passing behind the coverings will increase heat loss and create a considerable condensation problem.
Generally, the high cost of materials for insulating windows will make this a low priority item for most existing homes. If your windows need new shades or curtains anyway, consider methods for reducing heat loss at the same time.
One of the most practical solutions is to design or buy a flexible insulating curtain to pull across the windows or roll down from above. The curtain should ideally be made from a heavy, multi-layered material covered with your choice of fabric. Even one or two thick drapes over a window should do a good job if tightly fitted. The curtain should fit snugly along the window ledge, or be weighted for a tight fit along the floor. A valance or enclosure along the top is a good way to prevent air from falling behind the curtain.
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Why do I get condensation and frost on windows?
Condensation and frosting are common window complaints. Sometimes the problem is light fogging on some windows, other times there may be persistent and heavy frost covering the glass. Many homeowners buy new windows only to find out the problem has become worse.
Condensation occurs when water vapour in the air is cooled to the point where it condenses on the cold surface as water droplets or frost. The more humid the air and the colder the surface, the greater the accumulation of condensation. One solution is to reduce the humidity levels in the house. For more information on reducing humidity levels in the house, refer to the questions about house as a system.
Alternatively, you can increase the surface temperature of the window and frame. This can be done by having at least two layers of glazing; better yet are windows with a "Low-E"-type coating or triple-glazed windows. Frames should be of relatively non-conducting material, such as wood, fibreglass, or vinyl. Metal frames, even if they have a thermal break, may be more susceptible to condensation.
Often the condensation is between panes. This is a result of moist house air leaking past the first pane and condensing on the cold surface of the outer pane. Even dry houses can suffer from this type of condensation problem. This problem is common on second storeys where there is more air being pushed out the window because of the stack effect. The solution is to weatherstrip the inner sash to prevent air leakage; make sure that the weep holes are open to the outside.
If condensation occurs inside a sealed double-glazed unit, the problem can be corrected only by replacing the unit. Check to see if the window is still under warranty.
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How should I insulate dormer windows?
Many 11/2 or 21/2 storey houses also have dormer windows. The walls of the dormer may be insulated with batts, as described for the knee wall. Remember that the air and vapour barrier should be on the warm side of the insulation and sealed at all joints and corners.
The remaining walls and the dormer ceiling are much more difficult. The easiest solution would be to have insulation blown in. Remember to seal any ceiling fixtures or penetrations.
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Is it possible to replace only the panes (i.e., if a rock is thrown through the window) rather than the entire vinyl structure of a window?
It is easy to change the glazing unit in most, if not all, vinyl windows on the market today. In fact, the standard requires that all glazing units in residential buildings be easily accessible from the inside.
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How can we test a window for argon and krypton gases two or three years down the road?
Currently, there is no easy method to test the percentage of gas fill once the unit has been sealed. The only way to do so is to penetrate the seal with a special needle, extract a sample and have it analysed. This is expensive and often destroys the glazing unit.
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What should I know about glazing?
Windows should be at least double glazed. There are many ways to add extra glazing from the inside or outside, permanently or seasonally.
Single glazing has an RSI value of about 0.16 (R0.9), so it loses about 10 to 20 times as much heat as the same area of a properly insulated wall. Storm windows or double glazing will reduce the heat that is needlessly lost through the window in your house by almost half, while a higher efficiency window will reduce it by two-thirds or more! Improved windows will also make your house more comfortable by reducing drafts and increasing the temperature of the interior window, which would otherwise produce a cold feeling. Adding glazing also reduces the risk of condensation.
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We've been told that window units filled with argon and krypton offer no real advantages to ones filled with air. This is supposedly because the other gases are heavier and will leak out and be replaced by air if there is any slight puncture at the insertion point or in the seal. Is this true?
If there is no seal failure in the glazing unit (i.e., the panes of glass, the spacer bar and the sealant), current industry estimates hold that argon and krypton gas will "leak" out by osmosis at a rate of one to two percent per year. If the glazing unit is filled to proper specifications (90-percent argon/krypton or higher), then you can expect a reasonable energy performance for at least 15 to 20 years. If the seal fails, then all of the gas will leak out and be replaced with moist exterior air, which will eventually cause fogging or weeping between the glass panes. The entire glazing unit will then have to be replaced.
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What do I need to know about exterior storm windows?
Removable Single-glazed storm windows are designed to be installed each fall and removed each spring (unless you have air conditioning, in which case they stay in all year long). They can be made to order by suppliers listed under "Storm Windows and Doors" in the Yellow Pages. The major advantage of these removable storm windows over permanent ones is their lower cost.
These windows must be checked seasonally; damaged putty must be replaced and the frames painted regularly to preserve the wood. Conventional storms should not fit too tightly to avoid condensation between the storm and inner window. The inner window must be very well sealed with caulking or weatherstripping.
Permanent
The combination-type storm window has both screening and glass in the same unit, serving your needs year round. These windows have metal frames, and are made to order by specialized suppliers (under "Storm Windows and Doors" in the Yellow Pages). Installation can be done by the supplier or by you.
These permanent storms are more convenient than the removable type, but are also more expensive and cleaning between the storm and the window may be a problem. Some units have an energy-efficient low-E coating. Regardless of which type you choose, shop around for well-made windows. Look at the quality of hardware and weatherstripping and strength of joints. These windows are a long-term investment and can increase your property value, so quality construction is important.
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What do I need to know about polyethylene or rigid plastic interior storm windows?
Installing plastic sheeting over the window is an inexpensive and easy way to improve the heat retention of your home and reduce condensation. The plastic will be less durable than glass and will have to be re-installed each year if the windows are opened. There is an inexpensive kit on the market that has a plastic sheet that is heat-shrunk in place using a hair dryer. This system is best for windows in seldom-used rooms and basements.
A do-it-yourself plastic storm window is available, made of a sheet of rigid plastic and a specially designed snap-in frame. Some types use a magnetic strip to hold the plastic in place. The mounting strip is permanently attached to the window frame, and the strip pops open to accommodate the plastic sheets. The sheet can then be removed and stored in the summer. The sheets must be handled carefully, because they scratch easily.
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I just installed new energy-efficient windows and now I am occasionally getting condensation on the outside. Is something wrong?
No. Since the windows are energy-efficient and are not letting a lot of heat escape, the outside glass pane will cool down quite a bit at night. If the night is calm and the outdoor humidity is high enough, condensation will occur on the outside surface of the exterior pane of glass.
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How do I preserve the appearance of the older home when air-sealing around the doors and windows?
Windows are one of the most important aspects of a home's originality. Careful weatherstripping of older, single-pane, wood frame windows will do much to improve their energy efficiency. If the original wooden storm windows have been destroyed, it's possible to have custom wood storms made to order. If the object is to preserve the appearance of the building, avoid metal storms or storm and screen combinations.
If exterior wood storms are not desirable because of the maintenance factor, interior storms offer a good alternative. These are less noticeable than exterior metal storms, and they can be made to fit on the sash or the window trim. If the window sash is badly deteriorated, replacement units can be made to fit the existing frame.
Preserving the original doors is important to the overall appearance of an older home. Careful weatherstripping will improve their performance. As with windows, avoid aluminum storms. A better alternative is to restore the enclosed vestibule that is found in most older homes.
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When should I consider installing new windows?
Most existing windows can be repaired, weatherstripped, and have new glass added if necessary. However, there are circumstances when it is appropriate to buy new windows. New windows may be required when:
- the old windows have deteriorated
- there is extensive damage (such as rot) to the surrounding wall caused by the old window
- major renovations or additions require new windows
- you want changes in window size, operation, or the appearance of the house
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This article is from Natural Resources of Canada Web-Site