Last time we talked about how to find and what to look for in a good heating contractor. Now let’s move on to talk about what you’re buying, the furnace itself. We’ll start with a brief overview of energy efficiency ratings.

Efficiency Ratings

Furnaces are rated by a term called AFUE. Like miles per gallon on cars, AFUE, or the Annual Fuel Utilization Efficiency rates the annual gas consumption of a furnace. Today, furnaces are rated from 80% to 98% AFUE. Be a little bit skeptical of the commonly used term “high efficiency”. Just because a contractor claims they are quoting a high efficiency furnace doesn’t necessarily mean that it is truly high efficiency - high efficiency compared to what?

The majority of all furnaces sold last year were actually 80% AFUE, meaning up to 20 cents of every heating dollar spent is wasted. Additionally, AFUE doesn’t take into account electrical efficiency. True high efficiency furnaces start at 90% AFUE and go up to just over 98%, and they also utilize blower motor technology that reduces the furnace’s electrical consumption – which also improves the efficiency of cooling your home during the summer.

True high efficiency furnaces will also be ENERGY STAR® rated by the US Department of Energy, and will carry the ENERGY STAR logo. The ENERGY STAR program was designed in part to help drive innovation in energy reduction for appliances. Besides more cost effective high efficiency designs, there has also been a focused effort to improve heating comfort and airflow through your home. Today we are seeing rapid advancements in what we call variable heating capacity.

Variable Speed Furnace Technology

Variable-capacity operation works much like the cruise control system of high-performance automobiles, automatically making adjustments as necessary to provide the most efficient fuel usage. These high performance furnaces, automatically adjust heat and airflow capacity in increments as small as 1%. This technology is designed to provide the ultimate temperature control for your home.

Sound Reduction Technology

Sound has become a very important consideration when replacing a furnace, so another dramatic area of improvement for furnaces has been sound control. Newly sealed and insulated cabinets, unique blower technology and whisper-quiet burners combine to create operating sound levels where you often won’t even know the furnace is running.

Blower Motor Technology

As you evaluate new furnaces there is one more important consideration; be sure to consider the actual blower technology. The indoor blower in the furnace is used to circulate the air through your home. Without getting too technical, there are basically three primary indoor blower types available on furnaces today. Most furnaces installed today have a standard blower motor that has been relatively unchanged for the past 30 years. Standard motors are the least expensive and are the least energy efficient. Remember, AFUE only rates gas efficiency, not electrical motor efficiency.

The next step up in furnace blower technology is called Constant Torque motors. This technology strikes a balance between cost and energy efficiency. It provides an electrical efficiency boost over a standard motor design. And finally, there’s Variable Speed technology. The best furnaces today provide true variable speed motor technology, meaning the speed range of the motor is infinitely variable. So what specifically does that mean to you?

Provides the highest electrical efficiency available today, benefiting both heating and air conditioning energy costs.
Provides better control of humidity in the home.Provides a smooth transition through the motor’s speed range making it whisper quiet.

Furnace Warranties

In my experience, there are significant differences in furnace quality and reliability. Like any large purchase or appliance purchase we believe it’s best to purchase a major brand name HVAC system, even though most furnaces come with some kind of Manufacturer’s warranty. With a leading brand, you simply have more confidence in the technology, and ability for the manufacturer to stand by its product warranty over the long term. Just remember, your new furnace should last at least 15 years, and buying from a major manufacturer will help ensure yours does.

Most appliances come will come with some kind of Manufacturer’s warranty. Furnaces most commonly have two main warranty coverage areas. The first warranty coverage is on the heat exchanger. The heat exchanger is the heart of the furnace and arguably the most expensive component to replace. Heat exchangers typically have either a 20 year limited warranty or a lifetime limited warranty.

The second area of coverage for furnaces is a Main Component warranty. Coverage of main components usually includes blower motors, electronic controls, igniters and other key components of the furnace. Covered main components can have as little as a 1 year limited warranty to as much as a 10 year limited warranty. When reviewing warranty coverage it is very important for you to note all warranties are limited, you should be sure you understand the limitations.

For example, nearly all the standard manufacturer’s warranties only cover the cost of the replacement heat exchanger or replacement part. Labor, however, is not covered by the standard warranty… and labor on a replacement heat exchanger could get very expensive.

Equipment Registration

Another important consideration when discussing warranties is product registration. Many manufactures may limit the warranty term if the product registration is not completed, be sure to complete the manufacturer’s product registration - it’s simple and typically only takes a few minutes.

As we have discussed in the past, it’s very important to your new purchase to ensure you work with the right brand, and the right company… to get the right warranty and the best comfort system installation.

Next week we'll close our series with how to think about your Home as the Comfort System, and how to budget and pay for your new furnace.