« Continue Browsing

e-mail article Print     e-mail article E-mail

By James Dulley, Published November 20 2009

Try efficient glass or plastic block windows

Dear Jim: I am concerned about the security and efficiency of some of my old single-pane first-floor windows. I think glass block windows would be more secure. Are they efficient, and can I install them myself?

– Kathy W.

Dear Kathy: As people become more concerned about security at home, they are installing more glass and plastic block windows. This is particularly true for first-floor and basement windows where a would-be thief can hide and take time to quietly pry open or break a standard window.

It is possible to break through a glass block window, but it would be very difficult and create a lot of noise. Even though most glass block windows are hollow and someone may be able to break one, the opening is still not big enough to crawl through. Solid, high-security glass blocks are also available, but they are very heavy and more difficult to install yourself.

Plastic block windows are also available. Most are made from acrylic plastic, which is fairly impact-resistant. These windows are often installed as completed window panels to fit the wall opening. When installed, they look as though each block was installed individually.

Glass and plastic block windows can be energy efficient for several reasons. There is a sealed insulating air gap inside of each block. This is particularly efficient in glass blocks because the two halves are fused together under heat. When the blocks and the air inside the sealed gap cool, a slight insulating vacuum is created inside the block. Some plastic blocks have an efficient low-emissivity coating on the inner surface.

Another reason block windows are efficient is they are very airtight and remain that way throughout their life. There is very little, if any, air infiltration when the blocks are assembled properly in mortar or clear silicone. When installing a completed block panel, make sure to caulk well around the frame perimeter.

If you want the option of natural ventilation from your block windows, several of the blocks can be replaced with a small hopper window. The opening panel is made from tough polycarbonate plastic. It is too small to get through even if someone could break it. A hopper-style window closes on compression-type weatherstripping, so it is very airtight. Opening casement-style block window panels are often used in bathrooms.

It is not difficult to install block windows yourself. The large complete panels are installed similarly to any replacement window. Do-it-yourself kits for installing individual blocks are also available. Corner spacers are used to properly position the blocks. When the mortar sets up, the spacer ends are broken off and covered with more mortar. Kits for using clear silicone instead of mortar are also available.

The following companies offer glass and plastic block windows: Builders Accessories, (888) 921-7086, www.acrylicblock.com; Circle Redmont, (800) 358-3888, www.circleredmont.com; Glashaus, (815) 356-8440, www.glashaus.com; Hy-Lite Products, (888) 256-2599, www.

hy-lite.com; Pacific Accent, (888) 522-4527, www.pacific

accent.com; and Pittsburgh Corning, (800) 624-2120, www.

pittsburghcorning.com.


Dear Jim: I have two electric water heaters because I had a whirlpool that used a lot of hot water. I no longer use the whirlpool. Should I keep both electric water heaters working or turn one off? – Greg H.

Dear Greg: You should definitely turn off one of the waters heaters to save electricity. Even if the water heaters are new and energy efficient, heat will still be lost through the walls of tanks.

Do not disconnect the extra water heater because you may need it if the other one fails or if you decide to use the whirlpool again. Switch off the circuit breaker to it. Install valves to stop the water flow into it and from it and drain the tank.


Send inquiries to James Dulley, The Forum of Fargo-Moorhead, 6906 Royalgreen Drive, Cincinnati, OH 45244, or visit www.dulley.com