Dear Jim: I have a cat and dog that go outdoors into our fenced back yard. Much air, bugs and dirt blow in each time I open the door. Is installing a pet door a more efficient option, is one leaky and which is best? – Don H.

Dear Don: Whether installing a pet door is more efficient than opening the door for your pets depends upon how often they go in and out, the quality of the pet door and its orientation to the prevailing winds. Other intangible factors to consider are your time spent going to the door and your pet’s freedom of movement.

I have not seen any actual test data on this, but I would guess if your pets go in and out more than three times a day, it may be more efficient to install a good-quality pet door. Some pets, such as my cat, Buddy, prefer to stop halfway out the door and reconsider their decision. If your pets are similar, a pet door certainly makes sense for efficiency.

It is best to install the pet door on the east side of your house because prevailing winds are typically from the west year-round. In hot climates, the north side may be the best location for the pet door to avoid direct summer sun and breezes. In cold climates, the south side also is acceptable.

There are many types of pet doors available. In general, ones with a rigid door tend to seal better simply because the door flap fits better in the opening. Some models with flexible doors, which may be safer for the pet, use double flaps for greater energy efficiency (higher insulation and a better seal).

Some of the best sealing pet doors use a magnetic type seal similar to the weather stripping on a full-size steel front door. Flexible pet doors also seal fairly well against a soft foam bumper inside the opening. A pile seal on a door works smoothly but it can let outdoor air pass through on a windy day.

One of the most efficient pet door designs for sliding glass patio doors is built into a tall narrow rigid panel made with double-pane thermal glass. The pet door is located in the bottom of this panel. To install it, open the sliding door and expand the panel vertically into the sliding door tracks. Secure it so it cannot be removed. The existing patio door lock works with the latching mechanism on the pet door panel.

Another simple secure pet door design uses a locking mechanism with a magnetic sensor. I use a breakaway collar with a bell on Buddy so he cannot sneak up on birds. A tiny magnet is attached to his collar. When Buddy approaches the pet door in my sunroom, the magnetic sensor unlocks the door so he can get in or out. It also can be set for always locked or open and in- or out-only.

The following companies offer pet doors: Ani Mate, 936-760-4333, www.pet-mate.com; E-Z Matic Pet Doors, 800-593-3667, www.ezmaticpetdoors.com; Ideal Pet Products, 800-378-4385, www.idealpetproducts.com; Pet Safe, 800-732-2677, www.petsafe.net; and Solo Pet Doors, 877-766-3900, www.solopetdoors.com.

Dear Jim: We never use our fireplace and have stuffed insulation in the opening. There is bad odor coming from it even after we cleaned it. What is this odor and how can we stop it? – Linda S.

Dear Linda: There are many possible causes. Most likely, some animals are living in the chimney. The best solution to the problem is to remove the insulation, thoroughly clean the firebox and cap off the chimney top.

Before you cap off the top, make a lot of noise and wait a day or two for any animals to leave. Do it soon so the little animals have enough time to find a new home somewhere before the weather gets too cold outdoors.

Send inquiries to James Dulley, Bangor Daily News, 6906 Royalgreen Drive, Cincinnati, Ohio 45244 or visit www.dulley.com.