Complaints About Glass Block Basement Windows

Light Level

• Glass blocks used in glass-block windows are substantially thicker than traditional window panes. This means less light transmits through the material; even unfrosted glass blocks are more opaque than a traditional window. If you rely on natural lighting in your basement, glass blocks may reduce the amount of light with which you have to work. They cannot be opened, so the light level cannot be varied.

Ventilation

• Since glass-block windows cannot be opened, a homeowner may complain about ventilation issues in their basement. This especially is true in unfinished basements that are subject to flooding, as it may be difficult to air them sufficiently without the ventilation afforded by windows. A basement prone to water is not a good candidate for glass block windows, or a few windows across the back of the house should be left in for the purpose of ventilation and egress.

Egress

• Glass-block windows are poor when it comes to egress, or escape. In the case of an emergency, a glass-block window is as good as a cemented-over window. If a homeowner lives in an area subject to severe storms and uses their basement as a storm cellar, choosing glass-block windows may be a poor choice and may violate local safety codes.

Water Heater/Oil Burners

• In homes with water heaters and oil burners, or any basement appliance that requires combustion or burning of a fuel, a complete switch over to glass-block windows can be a problem. Glass-block windows are much more airtight than their traditional counterparts, and can seal off the basement and suffocate the pilot light on heating appliances. A separate combustion vent must be installed in the window closest to the heating appliances to ensure this does not occur.