Question - Every time I open the door for my pet, I get a gust of cold air or, in the summer, a swarm of mosquitoes. Are there inexpensive do-it-yourself automatic pet door kits available? - Pat F.

Answer - If your pet is like my old cat, Ralph, he never rushes to get through the door, always stopping half way out to scratch. By the time he finally gets out, the cold breeze has caused the heat pump to kick on.The wasted energy is even greater in the summer when pets go outdoors more frequently. Not only hot air and bugs come in but also humidity. This causes your air conditioner to work much harder.

Many easy-to-install pet door kits are available for almost any size pet. Door sizes range from 6-by-6 inches for cats to 18-by-25 inches for large dogs. The kits are designed to fit through doors, windows, screens and walls.

To block unwanted four-legged guests, select a pet door kit with a magnetic or battery-operated sensor. A tiny device, the size of a sugar cube, attaches to your pet's collar. Without it, the door will not open. Many of these models have "in only", "out only", "locked" or "full open" settings.

To keep track of whether your pet is in or out, select a pet door with an "in/out" indicator. These in/out sensor doors and other automatic pet doors are powered by several long-lasting AA batteries.

Solo makes one of the most sophisticated (and expensive) automatic pet doors. It has a motor and electronic sensor. As your pet approaches the door, it automatically slides up to open. Only your pet will open it.

A pet door is not a security risk and can actually enhance security by indicating the presence of a dog. What thief would break in or stick a hand in a pet door not knowing if a hungry Doberman is on the other side?

Most pet door kits are simple to install. The frames are made of unbreakable plastic or attractive anodized aluminum. Many kits offer additional inexpensive spacers so the kit can fit a thin door or a thick wall.

Although most pet doors use a flapper hinged on the top, several models use flexible doors vertically slit in the middle. This seals well and tends to wipe off mosquitoes and bugs as your pet moves through.

The newest pet door designs on the market are insulated, thermal glass panels that mount in the sliding glass door track. The pet door is built into the bottom, and the panel has security locks. Other new low-cost designs that mount in a window or door screen are also easy to install.

Write for (or instant download - Update Bulletin No. 995 - buyer's guide of 11 automatic pet doors, features, prices, door sizing/pet chart and instructions for a do-it-yourself insulated pet door. Please include $3 and a business-size SAE.

James Dulley, Deseret News, 6906 Royalgreen Drive, Cincinnati, OH 45244.

Question - I am trying to install a series of efficient low-sodium outdoor security lights, but I am having a real problem drilling into the concrete. I have gone through four masonry bits already. Any suggestions? - Pete J.

Answer - Your best bet to drill quickly in concrete is to use a rotary hammer drill. You can get one at any tool rental shop. The electricity savings from the new lights will pay back the rental fee in a month or so.

Once you have all the holes drilled, use expansion bolts, epoxy or simple lead anchors in the holes. Almost all hardware stores have a good assortment of anchors to fit any hole size.