Dear Glenn: I am about to purchase a new furnace and air conditioner. This is my first purchase of this kind, and the more I talk to heating and cooling estimators, the more confused I get.

I have estimates for a Lennox, Carrier and a Goodman (Janitrol). My house is one-story, a little less than 1,200 square feet and about 50 years old. I want a quiet furnace and air conditioning. Do you recommend a one-stage or a two-stage furnace? What about the SEER number for the air conditioning? Lastly, how about an air cleaner? Also, what is your opinion about having my air ducts cleaned and sanitized?

— Peggy, Detroit

Dear Peggy: All the major heating and cooling manufacturers are going to great lengths to quiet their furnaces and air conditioners.

Lennox currently has one of the quietest furnaces and air conditioners on the market. Two-stage furnaces are far more efficient than single-stage. SEER rating and price go hand in hand.

We do not have many cooling days in Michigan (compared to Florida or Texas), therefore a SEER Rating of 12 or 13 is probably sufficient. The higher the SEER Rating the more cost-efficient the air conditioner is to run. As the price of electricity goes up, the higher priced, high SEER units will be increasingly cost-effective.

It is a very good idea to have the duct work in a 50-year old house cleaned and sanitized.