Is Your Furnace Blowing Lukewarm Air? This Might Be Why.

A girl in winter clothing at her laptop computer. Via Justin Hall on Flickr.The weather is getting colder here in Monterey, and that means people are turning on their furnaces for the first time of the year. If you’ve turned on your home’s heat and found the air coming out of your home heating vents is lukewarm at best, you’re probably pretty frustrated.

Unfortunately, there can be many answers to the question, “Why is my furnace blowing lukewarm air?” Here are some of the most common explanations. Some are easily remedied by any homeowner, and some will require an HVAC professional to address.

Leaking Air Ducts

If your home’s air ducts are leaking, cold air could be making its way inside and mixing with the hot air produced by the furnace. This results in mild, lukewarm air emerging from the vents. Duct leaks can be caused by deteriorating seals, improper installation, and damage from pests. If you’re experiencing lukewarm are from your ducts in addition to symptoms of duct leaks like higher than usual utility bills, call a heating and cooling expert to diagnose the problem.

Problems with the Filter

If your furnace’s air filter is clogged or improperly installed, it may restrict the flow of air to the furnace burner. If the blower is still operating however, this will result in lukewarm air coming from the vents. A simple visual check should be enough to tell you if your furnace’s air filter is dirty. If it is, throw it away and replace it with a fresh one. If you’ve just done that, and there’s still a problem with the burner, the filter might be improperly installed. If you’re not confident replacing it yourself, call a professional.

The Thermostat is Set to “On” Instead of “Auto”

When the thermostat is set to “on,” the furnace system blows air whether or not the furnace is actually producing heat. This will result in lukewarm air emerging from the vents. Set the thermostat to “auto” and the fan will only run when the burner is actually producing heat.

A Problem with the Gas Supply or Furnace

If your furnace isn’t getting any or enough gas, it won’t be heating anything, much less the air coming from your air vents. Make sure there’s no problem with the gas supply. This problem could also be caused by a faulty thermocouple or flame sensor. If the burner’s not igniting and there’s no problem with the gas, contact a professional to investigate.

If your heat isn’t working and it’s cold outside, it’s imperative that you get it working as soon as possible. If self-troubleshooting isn’t doing the trick, call a professional right away.

For HVAC inspections and duct cleaning in Monterey, call Preferred Hood and Duct.

Image Credit: Justin Hall, licensed via Creative Commons