Steel exterior doors are insulated for energy efficiency
Q. My old wood front door leaks air and requires maintenance. I might switch to a steel door for low maintenance and security, but I was concerned about its efficiency. Doesn't steel transmit heat?
A. It is true that a chunk of steel is not a good insulating material, but steel doors are extremely energy efficient. When I moved into my house 20 years ago, it had a 10-year-old wood door. I replaced it with a steel door and the comfortable level in the foyer by the door was significantly better. Also, I heard much less road noise through it.
Next, I tested a fiberglass door in the same opening in my house. It insulated as well as the previous steel door, but it did not have the same hefty and substantial feel as my old steel door. The primary advantage of fiberglass doors is the graining, which I stained myself, which looks realistic. If you want a painted door though, a steel door is an excellent choice.
The reason a steel door is one of the most energy efficient is the steel skins are very thin and the indoor and outdoor skins do not actually touch each other. There is an insulating thermal break between them. The core of the door is made of foam insulation with a high R-value.
Another reason a steel door is efficient is the super-airtight weatherstripping. Most steel doors use magnetic weatherstripping which is similar to the seal around a refrigerator door. It actually sticks tightly between the two surfaces even if there is some variation in the gap. Most wood and fiberglass doors rely on compression or sliding seals.
Other than by price, it can be difficult to compare the quality of steel doors. The thickness (gauge of the sheet metal) of the steel skins also is often a good indicator of quality. Thicker skins resist dents better and are more secure against break-ins. When comparing skin thickness, a smaller gauge number means thicker steel; i.e., 24-gauge is thicker than 26-gauge.
Modern doors, whether they are made of steel, wood or fiberglass, tend to have a lot of decorative glass. From an energy efficiency standpoint, the glass is the weak link. Double-pane glass is the minimum quality level you should accept. Triple-pane is available for severe climates.
If you select decorative glass, look for styles with the decorative pane between two outer smooth glass panes. This effectively creates a triple-pane system with two dead air spaces. It also is easier to clean the smooth glass than a decorative surface with etching or a pattern cut into it.
Unless you are a pretty good carpenter, select a prehung steel door and frame. It can be difficult to hang a new door in an old frame and make it as airtight as a prehung one.
The following companies offer steel entry doors: Jeld-Wen, (800) 535-3936, jeldwen.com; Peachtree Windows and Doors, (800) 732-2499, peachtreedoor.com; Pella, (800) 883-6677, pella.com; Taylor Door, (800) 248-3600, taylordoor.com; and Therma-Tru, (800) 843-7628, thermatru.com.
Q. I have a three-season sunroom with single-pane windows. I want to try to keep it warm enough for my plants during winter. Would it help to cover it with clear plastic film and how would I hold it on?
A. It may help to cover the window areas or the entire sunroom with clear plastic film. The film will create a partial dead air space around the windows and this can significantly increase its insulation.
Find a clear plastic cover with perimeter eyelets. Use new Cordzilla stretch ropes to secure it over the sunroom. Cordzilla ropes have coated hooks, braided polypropylene sheath, and foam pads so the sunroom will not get scratched.
• Write to James Dulley at 6906 Royalgreen Drive, Cincinnati, OH 45244 or visit dulley.com.