Dear Jim: I want the best quality air at home for my family. I am trying to decide which type of central air cleaner is best. Will installing a central air cleaner make my heating and cooling more efficient? -- Steve D.
Dear Steve: Installing a high-quality central air cleaner in the furnace/air conditioner duct system does not technically improve the efficiency of your heating and cooling system. What it will do is keep the heating and cooling units running at their highest original efficiency levels.
With a lower-quality air cleaner, such as the standard 1-inch-thick fiberglass filter, dust and dirt can build up on the heat exchanger and cooling coil surfaces. This dust creates a layer of insulation so heat is not exchanged as effectively as it should be. This reduces efficiency.
Within the past year or two, several air cleaner and heating equipment manufacturers have come out with new super-efficient central air cleaners. They can even catch flu viruses and bacteria as they pass through the duct system.
Until this technology was developed, electronic air cleaners used wires of one charge and a collection cell of the opposite charge to catch the air particles. When the collection cell was dirty, it was washed off in the dishwasher, bathtub or outdoors and slipped back into the unit. The new super-efficient ones use collection media that is replaced, not washed.
For many people, the older technology is adequate. I use this kind of air cleaner in my own home. For people with allergies to some of the smallest particles in the indoor air, the new electronic air cleaners are more effective. The electricity cost to operate either type is not significant.
Another option is a pleated media air cleaner. This type of unit is less expensive and relies on many square feet of folded filter material to catch particles as the air passes through it. There are various levels of media quality and price. The cleaning effectiveness of various models can be compared by their MERV (minimum efficiency reporting value) rating.
If you do not want to have the ducts modified to install a new air cleaner, consider a self-charging electrostatic model. This slips into the existing furnace filter slot and is many times more effective than a fiberglass filter. Another option is a bypass HEPA air cleaner that has its own air circulation motor.