Shopping for a furnace? Don't spend thousands more than necessary

After 17 years, our furnace is wearing out. Earlier this week, the blower finally seized up, so we decided to bite the bullet and shop for a new furnace. Our house requires an 80-90,000 BTU furnace.

After listening to three salespeople extol the virtues of their brands and services, I thought I'd summarize the choices and price points. Consumer Reports contends that brands mean not so much, as they are so much alike and models change so frequently. Instead, I focused on quality and price.

Types of gas furnace. These come in three levels-

• a single-stage one like we currently have, that is either full-on or off;
• a two-stage model, allowing the furnace to use less gas in moderate temperatures;
• a multi-stage model that combines a two or three stage burner with a variable-speed blower that blows all the time, sometimes hard, sometimes soft, again based on need.

Furnaces also vary in the degree of efficiency, from 80% to 95%. Expect to pay more for greater efficiency, and expect your salesperson to push the value of fuel savings to offset the higher cost.

So, we have to choose among-

• 80% efficient single-stage
• 80% efficient two-stage
• 80% efficient multistage
• 90%+ efficient single-stage
• 90%+ efficient two-stage
• 90%+ efficient multistage (or modulating)

Are you with me so far?

Type of filtration
Air quality is another question we wanted to address, and the answers ranged from a simple furnace filter to an air cleaner.
Air cleaners come in two styles; a media filter (essentially a very thick (4-10") paper-like filter), or an electronic filter. The cost of the media filter is around 60-70% of the electronic filter. However, the electronic cleaner needs only be rinsed occasionally, while the media filter must be replaced a couple of times a year, at $40 or so a pop.

Humidifier
We have a humidifier we plan to keep, but if we were to upgrade, it would cost us several hundred dollars. The advantage of a new one would be that we could get one with its own thermostat, rather than having to remember to tweak the setting on the furnace-mounted control..

So what about quotes?
As you might expect, the quotes are not completely apples to apples. However, to give you a sense of the range of similar quotes:

For a 95% efficient, variable-speed modulating gas furnace and a media air cleaner-
Company A- $4,917
Company B- $3,709
Company C- $5,309

All three are well-established companies, Better Business Bureau Members, and top-rated by Angie's List.
The message to take from this? The harder a purchase is to comparison shop, the more likely it is that you can overpay. Comparison shopping for home repairs can save you a ton of money.