Quiet Furnaces | Tips for Buying a Gas Furnace thats Not Noisy!
Not much can let you down more than installing a new gas furnace and finding out you have a furnace blower that’s so noisy, it sounds like a train in your closet! Surely, when you were going over the gas furnace features, you didn’t tell the salesman you wanted the loudest and noisy gas furnace installed, so what went wrong? You’re old furnace, even though it no longer worked, was much quieter than this!
Tips for Buying a Quiet Gas Furnace
There are 4 main components related to the furnace that are going to generate much of the noises a furnace makes.
Furnace Efficiency Rating Effect on Noise
Today’s 80% AFUE Gas furnaces primarily use an “In-Shot” or a “Venturi” style burner, versus the older styles that simply heated up the ribbon of the heat exchanger. Picture a jet engine… when the pilot hits the afterburner. The result is that it sounds like a blow-torch when the furnace is running, and thus is much noisier than older models.
90% AFUE or higher furnaces use a sealed combustion chamber, so you rarely even hear the burners when the furnace is running!
- 80% AFUE Furnaces are Noisy, due to in-shot or venturi style burners.
- 90% AFUE or Higher are Quieter due to sealed combustion.
Single or Multi Stage Burners
It’s no secret that having a 2-stage furnace is going to result in a quieter running unit when its on a lower flame setting. The first, lower stage, of the furnace is like having a low-flame on your gas grill or stove turned on. Nice and quiet. The second (or third) stages of the gas valve open when higher levels of heat are needed, but they also result in a noisier furnace due to the added combustion and higher flame.
- Single Stage Gas Valves are Louder
- Two-Stage or Multi-Stage Furnaces are Quieter.
Fixed Capacity or Variable Speed Blowers
All you need to think of in this case is the blower in your car, or even the noise a hair blow dryer makes when its in different speed positions. Fixed capacity blowers are designed to blow at a set flow rate (measured in CFM) and they are On, or Off.
Turn the fan blower in your car 0onto the lowest setting, it’s almost like a whisper of air coming out of the vents. The minute you turn it to full-speed, or the highest setting, the blower gets much louder. The same holds true for a gas furnace blower.
- Fixed Capacity Blowers are Louder
- Variable, or Multi-Speed Blowers are Quieter when Running on Lower Settings (60-80% of the time)
Duct System Design and Efficiency
The final and likely biggest impact on the noise from your furnace is the duct system! If you have a furnace that’s moving 2000 cfm of air through a duct system that was designed to move 1400cfm, each vent is going to whistle, or sound like a leaf blower!
- Make Sure you Ask Your Contractor About the Duct in your Home, and if its designed to move the airflow the furnace is pushing!
Since many folks come here looking for the gas furnace noise ratings, we though it would be helpful to publish 3 of the quietest gas furnaces we know of!
- Lennox Signature Var-Speed Furnaces (Details | Website | Free Price Quote)
- Carrier Infinity Series Furnaces (Details | Website | Free Price Quote)
- Trane XC95 Var-Speed Modulating Furnaces (Details | Website | Free Price Quote)
Do you think you have the quietest furnace? Share the brand and model…