The whole point of having a good heating system in your home is to keep things nice and toasty during the cold months. So, if you find your furnace blowing lukewarm air into your house on a winter’s day, you’re going to want to fix it fast! Here are a few reasons why your furnace is blowing lukewarm air and what to do about them.

It’s Still Warming Up

If it’s the beginning of the season and you are turning your furnace on for the first time, it can take a while to get to full strength. The air may start cold or lukewarm, but give it some time to warm up. You’ll notice your furnace blowing warm air to start, then comes the hot air. If the temperature doesn’t change, call a professional to come check it out.

Leaky Ducts

Leaks are never good, including in your furnace. If there is a leak in your air ducts, that may be why your furnace is blowing lukewarm air. This is particularly common if you live in an old home with ducts that have never been replaced. 

The best solution is to identify where the leak is and then seal it. If the ducts need a lot of work, then replacing it is the best long-term solution. Again, an HVAC professional can help you navigate this decision and repair.

Dirty Air Filter

If a filter does its job right, it’s gathering dust and debris from the air blowing through it to keep it from entering your home. Naturally, over time, furnace filters get pretty clogged up with gunk and, if not replaced, can block air flow.

Why does this matter when it concerns your furnace blowing lukewarm air? When airflow is restricted or blocked, it can trigger your heater to turn off while the air keeps flowing. Switch in a new air filter, and you should be good to go.  

It’s a Two-Stage System

Check to see if you have a two-stage heating system. These furnaces are made to be more energy efficient, running for longer periods of time. However, because they run longer they have stages where the furnace is blowing warm air, not hot. Don’t worry, it’s supposed to do that! If you have a two-stage system, this is perfectly normal and there is nothing you need to fix.

It’s a Heat Pump 

If you use a heat pump to heat your house, the heat comes out at a lower temperature than other furnaces. For a heat pump, temperatures range from 90-100F (compared to a regular furnace which can reach up to 120-125). A heat pump just doesn’t get as hot, but it still heats your home. As long as the temperature of your home matches your thermostat, everything is working how it should.

Other Furnace Troubleshooting

If your furnace is blowing warm air or hot air like normal, problem solved! However, there may be other strange things happening with your furnace. These are 7 of the most common furnace repair issues:

Furnace is leaking water. This is often caused by a condensation leak, and can be fixed with the help of a professional. 

Furnace keeps turning off. This is probably due to a dirty air filter causing the furnace to “short cycle” and turn off due to the block of airflow. Replace your filter first to see if that fixes the problem.

Needing to relight the pilot light. You can do this yourself with these step by step instructions.

Furnace is blowing cold air. Make sure your furnace is set on auto, that your air filters are clean, and that the pilot light is on. After that, call a professional to check it out.

Furnace never turns off. Make sure your furnace is set to auto so that it cycles on and off.

Furnace is too loud. Furnaces can make noise sometimes. Check out this list of 8 common HVAC noises and how to fix them.

Furnace smells. If it smells like gas, there may be a big problem with a leak. Turn off your furnace, open some windows and leave the house ASAP. You’ll need to call your utility company to handle the leak. Other smells are less threatening but should still be looked into to make sure your furnace is running as it should.

Do I Need to Replace My Furnace?

If you’ve had ongoing problems with your furnace, it can be hard to know if it’s worth fixing again or getting a new one. After all your troubleshooting, here are a few ways to tell if it’s time to replace your furnace:

• Your heat pump is 10+ years old
• Your thermostat has been acting up
• Furnace is 15+ years old
• You have too many furnace repair visits
• You sense your furnace might be giving off fumes and making your family sluggish. In this case, take action immediately!

The Heat is On

If you still can’t figure out why your furnace is blowing lukewarm air, or you need help troubleshooting any other furnace issues, we are here to help all winter long. It doesn’t matter what time or day, give us a call to help you figure out all our furnace-related issues.