• I'm about to replace my furnace and have noticed that, on very cold days, it seems to run constantly. Should I get a larger unit?
  
• What is the definition of the term "AFUE"?
  
• Should I turn off the pilot light on my furnace during the summer?
  
• What is a "90 plus" furnace?
  
• I currently use propane or LP gas for heating and water heating, but have natural gas available - should I consider switching?
  
• With a gas furnace (or water heater), what does the color of the flame indicate?
  
• What is the most efficient type of gas furnace?
  
• What is the best replacement option for an older gas "floor furnace"?
  
• Should I install carbon monoxide detectors in my home?
  
• When I first turn on my furnace at the beginning of the heating season, I notice a slight odor, as if something is burning - is this carbon monoxide?
  

Q. I'm about to replace my furnace and have noticed that, on very cold days, it seems to run constantly. Should I get a larger unit?

A. A gas furnace is most efficient when it runs for long periods of time (much as you get better gas mileage driving on the highway). A properly sized furnace should run almost constantly on very cold days. As long as the furnace is capable of maintaining a comfortable temperature, you probably don't need a larger one.

Q.What is the definition of the term "AFUE"?

A. AFUE or "Annual Fuel Utilization Efficiency" is a measure of how efficient the furnace is over an entire heating season. The higher the number, the more useable heat you will get for every unit of fuel. A furnace with an AFUE of 80% will provide 80 cents worth of heat for every dollar of fuel.

Q. Should I turn off the pilot light on my furnace during the summer?

A. The pilot light on a furnace can use several dollars worth of gas each month, so you can save by turning it off. If you are hesitant to try to relight it, you can ask your heating contractor to light it at the time of your annual service before the heating season.

Q. What is a "90 plus" furnace?

A. The term "90 plus" refers to the AFUE or percent efficiency. These high-efficiency furnaces are also referred to as "condensing" furnaces, as they extract so much heat from the exhaust gases that the moisture in the exhaust condenses, releasing additional useable heat. While these units cost somewhat more than a conventional furnace, their lower operating costs can actually make them a better investment over the life of the unit.

Q. I currently use propane or LP gas for heating and water heating, but have natural gas available - should I consider switching?

A. Definitely. Natural gas is both less expensive and more convenient, and the modifications needed to your furnace and water heater are relatively minor.

Q. With a gas furnace (or water heater), what does the color of the flame indicate?

A. If the system is operating properly, the flame should have a bluish color. A yellow flame indicates a need for adjustment and should be checked by a qualified service person as soon as possible.

Q. What is the most efficient type of gas furnace?

A. There are several types of high-efficiency gas furnaces available. A condensing or "90 plus" furnace is typically rated at 89-93% AFUE, as compared with 78-80% for a new conventional-type furnace. Pulse furnaces, which work much differently, can have AFUE ratings as high as 97%.

Q. What is the best replacement option for an older gas "floor furnace"?

A. It depends on a number of factors. If you want to add central air you will need to add a duct system, which can be expensive. If you do add ducts, a new gas forced-air furnace would be a good option. If you can't or don't want to add a duct system, consider natural gas space or room heaters, which will give you more flexibility and temperature control.

Q. Should I install carbon monoxide detectors in my home?

A. Carbon monoxide detectors are recommended whenever a fossil-fuel heating system or water heater is present. In most cases, the danger of a heating system or water heater producing carbon monoxide is minimal, but under certain conditions any combustion process can produce carbon monoxide. Since carbon monoxide is colorless and odorless, it can go unnoticed unless a detector is present.

Q. When I first turn on my furnace at the beginning of the heating season, I notice a slight odor, as if something is burning - is this carbon monoxide?

A. No - carbon monoxide is odorless. If the smell lasts only a short while, it is most likely some dust or dirt being burned off of the heat exchange surfaces, and is harmless. If the smell persists, have a qualified contractor check your system.