Your Heat Won't Turn On After Summer: What to Check Before Calling for Service

Every fall the same thing will happen to many Northwest Arkansas homeowners.

After months of running our air conditioners nearly nonstop during a record-breaking summer, we’re finally getting our first cool mornings and chilly nights. Naturally, you walk over to the thermostat in the hallway, bump up the temperature and then… nothing happens.

Don’t panic! Before assuming something is seriously wrong with your heating system, there are several things you can check. In fact, sometimes the solution takes only  a few minutes. 

1. Make Sure the Thermostat Is Actually Set to Heat

It sounds obvious, but thermostat settings are one of the first things worth checking after a long summer. Make sure the thermostat is actually set to HEAT, not FAN and not OFF.

Then raise the temperature a few degrees higher. Most HVAC systems will not begin heating unless the thermostat is actively calling for heat. Keep in mind that some systems also have a short built-in delay before starting, so be patient and give it a few minutes.

2. Check the Thermostat Batteries

Weak or dead batteries can prevent it from communicating properly with your HVAC system and switching over to the HEAT setting.

Of course a blank display is an obvious sign, but a thermostat can sometimes continue displaying information even when its batteries are too weak to send a single to your system.

Replacing the batteries is a quick step that can rule out one of the simplest potential causes.

3. Check Your Circuit Breaker

Your heating system still relies on electrical power even though your furnace is powered by natural gas. Check your home's electrical panel and look for a breaker labeled HVAC, furnace, air handler or heat pump.

If a breaker has tripped, you can reset it. 

However, if it  trips a second time, do not continue resetting it. A repeatedly tripping breaker can indicate an electrical or equipment problem that should be inspected by an HVAC professional.

4. Look for the Furnace Power Switch

Many furnaces have a standard-looking wall switch located near the equipment. Because it looks like an ordinary light switch, it can sometimes be accidentally turned off during cleaning or maintenance. 

Make sure the switch is in the ON position.

5. Check the Air Filter

A severely clogged air filter can restrict airflow enough to create problems with your heating system, especially if it hasn’t been changed since early in the summer. Modern furnaces include safety controls that may shut the system down if internal temperatures become too high. Restricted airflow caused by a dirty filter can sometimes contribute to that condition.

If your filter is visibly dirty, replace it with the correct size and type recommended for your system. 

Changing your filter regularly can also improve airflow and help your HVAC system operate more efficiently throughout the heating season. We recommend changing your filter every one to two months. 

6. Make Sure the Gas Supply Is On

If you have a gas furnace, make sure the gas supply has not been turned off, especially if your home only uses gas for heat and not for cooking or hot water.

However, if you smell natural gas or an odor resembling rotten eggs, do not try to troubleshoot the furnace yourself. Leave the building and contact your gas utility or emergency services from a safe location.

7. Check Whether Air Is Coming From the Vents

If the system appears to be running but your home is not getting warmer, check the airflow from several vents.

Little or no airflow could point to a blower problem, clogged filter, duct issue or another mechanical problem.

If air is moving but it never becomes warm, the issue could involve the furnace's ignition system, heat pump components, thermostat controls or another part of the heating system.

All of these problems generally require a professional diagnosis to determine the necessary repairs. 

When Should You Call an HVAC Technician?

If you've checked the thermostat, breakers, filter and obvious power switches but your heat still won't come on, it's time to have the system looked at by a licensed HVAC technician.

You should definitely call for service if you notice any of the following:

• Repeated breaker trips

• Unusual electrical or burning odors

• Loud banging, grinding or buzzing noises

• A furnace that repeatedly starts and shuts off

• A heat pump that runs but does not warm the home

• Error codes or any warning lights

• Smoke or visible electrical damage

  
  

Problems that appear during the first heating cycle of the season are not unusual.

Components may have gone unused for months, and an issue that developed during the summer may not become obvious until you ask the system to heat again.

Don't Wait for the First Freeze

The weather in Fayetteville can change quickly in the fall. A mild afternoon can turn into a chilly night with little to no warning.

Testing your heating system before you really need it gives you time to identify problems before the first major cold snap and before HVAC service schedules become much busier. The last thing we want is you waiting for service in a cold house.

RJW Mechanical provides heating repair, maintenance and system service throughout Northwest Arkansas. If your furnace or heat pump won't start, isn't heating properly or simply needs its seasonal inspection and maintenance, our team is here to help determine what's wrong and get your system ready for colder weather.

Need heating service? Contact RJW Mechanical at (479) 443-9331 to schedule an inspection or repair.