Healthy House Windows

Window in a staircase of the Zinna monastery near Jüterbog south of the german capitale Berlin. Windows bring sunshine and fresh air into your home, but if you have any chemical sensitivities, you should be careful when putting in new windows or replacing old ones.

For example, wood frame windows can be made with chemically treated wood, plastic frame windows can outgas volatile odors, and rubber seals and some types of caulking can also outgas.

Windows vary in terms of glazing, sealing, frames and construction types. Old-fashioned double hung windows will create the least air seal, while casement windows provide the tightest seal. Loose fitting windows will let airborne pollutants into your home environment.

Glazing

It is pretty rare for someone to be sensitive to the actual glass panes in windows, since it is an inert material. Plastic films and coated glass are on the market which can raise the energy efficiency of your windows. These low E coatings can outgas if they applied to the outer surface of windows, although if they are on the inner surface of double pane windows there should be no such problems. Avoid the type of glazing applied to glass to make it unbreakable or shatterproof, since these polycarbonate and acrylic coatings are plastics that can outgas.

Glazing putting or compound, used to hold glass in the frame, is applied to the exterior side of the frame. The traditional product rubber or vegetable oil based material, but synthetic rubber extruded seals are growing in use, particularly with metal frame windows.

These rubber seals can outgas as well. The sensitive individual should try to find a window which has the lowest amount of outgassing materials used in it, which would probably be a double pane anodized aluminum frame window with uncoated glass or coating on the inside.

The one drawback to metal frames is the moisture condensation that can form in cold weather, leading to mold growth. The condensation can be prevented by the inclusion of a feature in the window called a thermal break. Thermal breaks insulate the outdoor surface of the frame from the interior surface.

Wood Windows

All wood frame windows, as mentioned previously have the drawback of being treated with water resitant preservatives, which contains fungicides, waxes and resins in a mineral oil base. The typical fungicides currently being used are kown to be toxic to wildlife and domestic animals (Tri-N-butylin oxide, 3-ido-2-propynyl butyl carbamate) and should be avoided.

Building your own wood window frame units without chemical treatments is feasible, but you will have to contend with moisture rot, fungus, mold and insect problems if they are not properly painted and maintained. Solid redwood would be the top choice for wood.

Photo by Till Krech, Creative Commons Attribution License