​​​​​​​​​​​Natural Gas Forced-air Furnace​s

Today's natural gas furnaces are up to 98 percent AFUE, helping you lower your heating bills for years to ​​come. They provide reliable, even heat to keep your family warm and comfortable. 

Maintaining Your Furnace​

Your natural gas furnace is a very dependable performer.  However, all home heating systems need periodic care to extend their operating life, save energy and maintain their efficiency​ rating. Use the following as general guidelines, but follow manufacturer's recommendations whenever possible.

  • Check your furnace filter monthly and replace according to manufacturer specifications.
  • Have a licensed professional service technician check your furnace annually to make sure it is running safely and efficiently. Consider timing your annual service call for late summer to "beat the first frost rush".
  • Inspect the "cold-end' of the flue for ice build-up that could restrict exhaust.
  • Ensure that the fresh-air intake is free of debris, snow, ice, etc.

Contact a Professional Service Technician​

Have a professional licensed service technician check your furnace annually to make sure it is running safely and efficiently, or when it is not working properly.

Signs include:

  • ​Odors and/or irritation to your nose or eyes. ​​​If you smell gas​, leave the area immediately. Do not use your phone, electric switches, your computer, or anything that could cause a spark. Go directly to a safe location, and then call CenterPoint Energy and 911.

24-hour gas leak hotline
Minneapolis/St. Paul Area: 612-372-5050
Toll-free: 800-296-9815

Other reasons to contact a professional licensed service technician:

  • ​Soot and carbon deposits on the burner, in the combustion chamber, on the floor near the furnace/boiler or below the draft hood opening
  • Buildup of dust, dirt or scale on burners and/or burner components
  • A yellow flame rather than a blue flame
  • Flame backing up and burning outside the combustion chamber
  • Excessive humidity or frost on windows or walls
  • Any repairs or adjustments to the valves, burners, pilot safety and limit controls should only be done by a qualified professional.
  • If the pilot goes out, look for relighting instructions printed on the furnace. If it goes out repeatedly or you are not comfortable relighting the pilot, call a qualified heating contractor.
  • A professional service technician should replace chimney and vent connectors (the pipe between the furnace and the chimney) if there are rust holes or corrosion.

Shopping for a Furnace

You should consider replacing your furnace if:

  • ​It is more than 15 years old 
  • Current system needs frequent repairs
  • Doesn't start at the beginning of the season 

Buying a furnace or other home heating system is one of largest purchases you'll make.  Here are some things to consider when shopping for a furnace.

Do your homework​​

Energy efficiency and rebates

  • A higher efficiency furnace may cost more to purchase, but it can offer significant savings on your heating bills, depending on the equipment you buy. Although the purchase price may be higher for a more energy efficient model, remember, you will usually regain that extra cost and more in energy savings over the life of the unit.​
  • CenterPoint Energy offers rebates of up to $400 for high-efficiency forced-air furnaces. Receive a $25 rebate when your dealer installs a new programmable thermostat (PDF)​ with your new boiler. Ask your dealer show you how much you can save on your energy bills when you upgrade your heating system with our "Efficiency Pays" slide rule. 

Gas verses electric - operating cost and environmental impact
  • Operating costs with gas are typically about 50 percent lower than with electric; natural gas is significantly cleaner than electricity, with half the carbon footprint.
Choosing a dealer
  • ​Buy from a reputable dealer. Choose someone you can trust that sells quality brand furnaces. This is a big purchase. Consult with the BBB, trade associations, friends and neighbors - and ask for referrals. Follow-up on customer testimonials offered by the contractor.
  • The contractor should perform a heat loss calculation on your home to properly size the furnace. Replacing the furnace based on the size of the old one is not accurate. Over the years, a lot may have changed since the old one was installed, including added insulation, new windows, or even a new room.
Get two or three estimates
  • When you get estimates, compare efficiencies and installation costs of various models. Be sure the estimates from one dealer to another cover the same work, from permits to removing the old unit to installing the new to clean-up after the work is done.
Replace your water heater and heating system at the same time
  • ​An "orphaned" water heater is a storage tank style residential water heater that is left alone as the only combustion appliance vented to a chimney after a furnace or boiler is removed. The best way to avoid potential issues with an orphaned water heater is to replace it at the same time you replace your inefficient furnace.

Not replacing your old water heater when you upgrade your furnace or boiler can lead to potential issues ranging from leaking to carbon monoxide hazards. To learn more about orphaned water heaters, view the ​Minnesota Department of Commerce, Division of Energy Resources (PDF)​​ fact sheet.

Energy Saving Tips

Here are some steps you can take to save energy and help lower your heating bills.

  • Weatherizing your home will go a long way toward reducing energy loss and lowering your winter heating bills.  Take the first step with a Home Energy Audit.  A professional Home Energy Audit provides customers direction on simple, effective ways to increase home energy efficiency.
  • Lower your thermostat at night and when there will be no one home for at least four hours. A 10 F setback can give you significant savings. 
  • Programmable thermostat (PDF)​​ save energy by automatically turning the thermostat down and up on a schedule you can easily program.
  • Check register​s. Look for and correct the following:
    • Drapes, furniture, clothes piles or towels obstructing the warm air supply and/or return registers or grilles.
    • Keep the warm air supply​ and/or return registers or grilles clean of debris.

Safety and Your Natural Gas Furnace​

  • Keep the area near the furnace clear of flammable liquids (gasoline, paint products, solvents or cleaners) and all combustible materials (newspaper, cardboard boxes or rags).
  • Furnaces will run longer during very cold weather, be aware that supply ductwork and registers may be hot to touch.
  • A professional service technician should replace chimney and vent connectors (the pipe between the furnace and the chimney if there are rust holes or corrosion.
  • Inspect the "cold-end" of the flue for ice build-up that could restrict exhaust.
  • Ensure that the fresh-air intake is free of debris, snow, ice, etc.
  • Have your furnace checked by a professional licensed service technician once a year to be sure it is performing properly and that it has sufficient air for proper combustion and to exhaust flue products.

Carbon monoxide safety​​

Check frequently for visible signs of carbon monoxide​ (CO) build-up in your home or building, such as high indoor humidity, and soot or water collecting near a burner or vent.