Q: I have to let my cat and dog in and outside many times a day. A gust of cold air blows in each time. Will a door-mounted pet door really help much, and can I make one myself?
A: Opening your door several times a day to let your pets in or out wastes a lot of heat in the winter. In the summer, it allows heat and humidity to get indoors. If your pets are like my cat, they never seem to be in a hurry to get through the door.
A pet door that mounts in the bottom of your door saves energy. In addition to being a much smaller open area than a regular door, a pet door is only open when your cat is actually moving through it. It is not held open while your cat makes up its mind to come in or go out.
Good quality cat and dog pet doors often use a brush-type weatherstripping that seals well when it is closed. This not only reduces heated room air loss, but it reduces drafts in your home, so you can often set your thermostat down a degree or two.
One of the most effective types of pet doors uses a battery-operated electro-mechanical lock. You can select "in-only," "out-only," "both," or "locked." The door itself is made of clear plastic so your pet can see through it and is not frightened walking through it.
Your pet wears a small collar with a special small magnet on it. A sensor in the pet door senses the magnet and allows only your pet to enter or exit. Without the collar, it will not open. That keeps stray cats or other small animals from visiting on cold winter evenings.
Another design of pet door has the same four settings but without the magnetic-sensing lock. Others use a flexible clear plastic that bends in or out. Magnets are used to center the door in the closed sealed position.
These pet doors are very easy to install yourself. You just saw a hole through the bottom of the door and screw the indoor and outdoor halves over the hole. They are made with attractive trim panels. Special kits are also available to mount a pet door through a glass patio door panel.
You can easily make an insulated pet door yourself. Make a plywood tunnel frame and hang a door from a hinge at the top. Glue rigid foam insulation board to the door. You can also make a two-door unit with one "in-only" door and one "out-only" door. This allows you to use a tighter-sealing type of weatherstripping.
You can write to me for "Utility Bills Update No. 317," listing addresses and telephone numbers of manufacturers of the new magnet-sensing and other pet doors, product information, and instructions for making an insulated pet door. Please include $1.50 and a self-addressed business-size envelope.
Q: I have a cracked pane of glass in one of my windows and I think that I can feel a slight air leak through it. Does much air leak in a crack and what is the easiest way to repair it?
A: Quite a bit of air can leak in and out of a crack in window glass. The size of the crack can vary depending on weather conditions and the season. You should replace it with a new pane.
Write to James Dulley, c/o Baltimore Sun, 6906 Royalgreen Drive, Cincinnati, Ohio 45244.