Dear Jim: I am considering a central vacuum system because of my children’s allergies. Should I vent it outdoors even though it will suck air out of the house? Are more powerful models best even though they use more electricity? – Kim H.

Dear Kim: Installing a central vacuum cleaner is probably your best vacuum system option for removing allergens from the room air. Even though many of the small, but powerful, canister vacuum cleaners have high-quality HEPA filters, the exhaust air will still contain some very fine particles.

I have allergies to mold, dust and pollen myself, and I use a central vacuum cleaner most often. A good quality HEPA canister vacuum still comes in handy though for quick cleaning of small areas. Even with the new lightweight central vacuum hoses, it is still quicker to get out a small canister model.

If your primary concern is removing allergens, then venting the central vacuum outdoors is an option, but not necessarily the best. As you mentioned, it will suck much conditioned air from inside your home and this increases your utility bills.

When indoor air is sucked from your home, it is replaced by outdoor air which leaks in through cracks, around windows, etc. If your family is allergic to pollen and other outdoor allergens, the outdoor air which gets drawn indoors may contain more allergens than were in the indoor air initially.

With the multistage filtration systems which most central vacuum system have, indoor venting is usually preferable. Some of the manufacturers, such as Beam’s Serenity Plus, offer units with extra soundproofing, exhaust filters and mufflers to reduce the noise level indoors. Utility rooms and basements are common indoor locations for the central power unit.

More powerful models have greater cleaning power, so they are generally your best choice if you can afford their higher price. A more powerful one will clean faster and more thoroughly, so the additional amount of electricity used is not great. If your budget is limited, most dealers have guidelines for the minimum amount of power required for various-sized homes.

It is possible to install a central vacuum system yourself, but most people have one installed by the dealer. The systems use PVC piping which is assembled similarly to plastic drainage pipe in your home. In a two-story home such as mine, the main pipe is run in the corner of a first-floor closet to the second floor.

Safe low-voltage wiring is run to each outlet to switch the power unit on when the hose is inserted in the inlet. MD Manufacturing has an optional electronic control system, Power3, which eliminates the need for the wiring. This simplifies installation, eliminates future broken wire problems and makes it compatible with a fully automated home systems.

The following companies offer central vacuum cleaners: Beam (800-369-2326, www.beamvac.com), Electrolux (800-896-9756, www.electroluxusa.com), Eureka (800-282-2886, www.eurekaco.com), MD Manufacturing (800-997-2278, www.builtinvacuum.com), and Nutone (888-336-3948, www.nutone.com).

Send inquiries to James Dulley, 6906 Royalgreen Drive, Cincinnati, OH 45244, or visit www.dulley.com.