My Home Furnace Air Doesn't Feel That Warm

Filters

• Furnace filters are designed to trap particulate matter such as dust and pollen. They need cleaning or replacing, depending on the type of filter your furnace requires. The U.S. Department of Energy advises that some temporary air filters need replacing every month, while others need replacing every three months. Permanent filters need routine cleaning, some as often as every month, depending on the amount of trapped debris. Dirty filters restrict airflow and reduce the output of warm air to your home.

Dirty Burners

• Furnaces have burners that ignite and heat air that is forced through ducts to warm your home. Burners can become dirty from soot deposits that clog the orifices and limit air output. Burners can also become cracked, out of adjustment, or out of alignment. Any of these problems can reduce airflow and deliver insufficient heated air through vents, making the air feel cooler. Carbon monoxide poisoning is another consequence of dirty burners and dirty furnaces, but it is only detected through testing since this gas is colorless and odorless.

Blowers

• Air is moved from the furnace by a blower fan that forces air through ductwork. If there is a malfunction with the blower fan motor, the motor cannot perform properly. Loose wires, a faulty motor or a dirty motor can cause malfunctions. Airflow may be significantly reduced and will not feel as warm coming through vents. Your system will run longer than it should, and your home may not warm up to a comfortable level. HVAC professionals should be consulted to diagnose this problem and make recommendations.

Leaky Ducts

• Ducts can leak where they join together if they are not properly sealed. According to the Lawrence Berkeley National Laboratory, duct tape is the least reliable method for sealing duct joints. The California Energy Commission recommends using mastic, an adhesive compound that hardens as it dries and forms a tight seal at duct joints. When ducts leak, warm furnace air escapes through joints and cold air from unheated spaces is pulled into ducts. The cold air travels through ducts until it comes out vents.