Buildings

Central House Vacuum System

Q: My friend Becky says we really ought to install a central vacuum cleaner system in our new house when it's built. She says regular vacuums just stir up the dust in the house and can actually make the air dirtier. She's kind of a hypochondriac, though, so I take her advice with a grain of salt, but my son does have asthma and if this would help I'll do it.

A: Becky may be a hypochondriac, but she's a smart one, so listen to her. Of course, depending upon a vacuum cleaner to keep the air in your house clean is a little like removing all the booze in your house in order to keep alcoholic uncle Harold sober. It's okay as far as it goes, and it may help, but it's certainly not sufficient by itself.

Since your son has asthma, it's important to pay attention to maintaining good indoor air quality in your house. One of the best ways to do that is to use finishes and furnishings that are easy to clean. Surfaces that can be damp-mopped, such as tile, linoleum, wood, or even concrete, tend to collect less dust and dirt than carpet or upholstery, and wiping them off spreads less dust than sweeping or vacuuming. Carpet and many upholstery fabrics also tend to collect biological contaminants like molds and bacteria, and under certain conditions those creatures can thrive and grow in your carpet or in your couch.

If you do have carpet, or other surfaces that need to be vacuumed, a central vacuum cleaner, exhausted to the outside, is more likely to remove dirt, dust mite droppings, cat hair, and the bacteria growing on the petrified Spaghetti-O's than a standard, portable vacuum.

Most vacuum cleaners have two basic problems: 1) a lot of the "fine" particles go right through the bag and are broadcast throughout the house; and 2) the exhaust air stream coming out the back of the machine stirs up the dust all over the house, putting a lot more into your breathing zone. Think of the back of your vacuum cleaner as a mini leaf blower, and you'll get a good image of what's happening when you turn on the machine. Better yet, run your vacuum cleaner in a dark room and shine a flashlight on the air coming out the back. You may be surprised by what you see.

Some companies have come out with high efficiency (HEPA) filters for their machines, which are extremely efficient at collecting even tiny particles, if the unit itself is well-sealed and actually directs all the particles through the filter. Some of these machines cost a heapa money — as much as a central system--and still don't solve the problem of the exhaust air stirring up dust. In an existing home, where installing a central system may be prohibitively expensive, a good portable with a HEPA filter may be the next best choice.

In order to get the advantages of the central unit, be sure it's exhausted to the outside. I once went into a house with the central vacuum system canister mounted in the garage, with no exhaust pipe to the outside. In this house the air handler unit for the air conditioning system was also in the garage, and there were leaks in the return ducts. If the people ran the vacuum cleaner when the air conditioner was running, much of the air coming out of the vacuum, along with the fine dust particles and other nasties, were being sucked right into the air conditioning system and spread around the house.

A good vacuum cleaner--particularly a central system exhausted to the outside--can be part of your strategy for providing a healthy home for your son. But pay attention to the basics first — eliminate whatever pollutants you can; separate others from the living space; and install good ventilation and filtration systems. Once all that has been taken care of, the vacuum cleaner can help maintain a clean environment.