Furnaces

What are furnace ratings?

Furnaces are rated by the Annual Fuel Utilization Efficiency (AFUE) ratio, which is the percent of heat produced for every dollar of fuel consumed.

Like the miles-per-gallon rating on your automobile, the higher the AFUE rating, the lower your fuel costs. All furnaces manufactured today must meet at least 78% AFUE. If your furnace is 10 – 15 years old, it very well may fall below the current furnace minimum and waste energy.

This doesn't mean that you should only select a furnace based on its AFUE rating. The efficiency rating is just one factor to consider when looking for a new furnace.

Furnaces use electricity to run fans and motors. The amount of electricity used varies greatly depending on the type of furnace. Be sure to check electricity usage prior to making a purchase decision.

What is two-stage heating?

Two-stage heating means the furnace has two levels of heat output: high for cold winter days and low for milder days. Since the low setting is adequate to meet household-cooling demands 80% of the time, a two-stage unit runs for longer periods and provides more even heat distribution.

Longer, low-capacity operation has many advantages:

  • Consistent comfort Two-stage heating eliminates the temperature swings associated with standard furnaces, regulating temperature to within as little as one degree of the thermostat setting.

  • Quiet operation Two-stage furnaces start in the first stage, when the amount of heat required is lower, instead of reaching full capacity all at once. That means there's no sudden "kick" or blast of air.

  • Improved air filtration Low-speed operation allows your filters to capture more contaminants (because air is constantly passing through them), so you can breathe easier.

  • Efficient performance Because the furnace operates mostly in its lower-capacity first stage, it burns less fuel than a standard furnace that always runs at full capacity and shuts off when the heating demand has been met.

What is a variable speed furnace?

The term "variable speed" refers to the furnace's indoor blower motor, which moves at different speeds to precisely control the flow of heated and cooled air throughout your home. Better airflow control has several benefits:

  • Electrical efficiency Variable speed motors can actually save you money on your energy bills, as they consume less electricity than standard motors.

  • Cooling efficiency Variable speed technology also means you will gain heating efficiency or AFUE.

  • Zoning Variable speed motors are excellent for zoning, which allows you to customize your comfort in different areas of your home and control your energy bills.

  • Air quality a variable speed motor can also help clean the air in your home. When the fan is in constant operation (indicated by the "Fan" setting on your thermostat), the motor will continue to slowly circulate air, allowing filters to capture more contaminants.

  • Humidity control a variable speed motor combined with a Comfort Sense 7000 programmable thermostat Home Comfort Control allows you to control the amount of humidity in your home for improved indoor air quality and comfort.

Can I use my chimney with my new furnace?

Furnace technology has advanced significantly in recent years, raising concerns over chimney use. As a result of changing technology, many existing masonry chimneys aren't able to meet the specific demands of new furnaces.

There are several reasons for this furnace-chimney incompatibility. First, the size of the chimney can be an issue. Modern, higher-efficiency furnaces transfer more heat into your home and less heat up the chimney than older, less-efficient units. While this means more efficiency for your energy dollar, it also means that the existing chimney might be too large for the new furnace. The result could be improper ventilation of flue products, which can cause condensation problems inside the chimney.

Other considerations include chimney height and location, proper lining and condition of the chimney. Building codes must also be kept in mind to ensure proper draft in the chimney for adequate ventilation.

For the best advice on how to configure your new furnace, please call us.