Reasons for a Central Unit Not Blowing Heat

December 21, 2022

You switched on your central heating system, but it blows lukewarm or cold air. This is not a good scenario to start the winter. Being too cold is not only uncomfortable; it can be harmful to people and pets. If you’re wondering why your central unit is not blowing heat, call Service Champions to come to your home and check your furnace or heat pump.

Here are some reasons your central unit is running, but not heating your home:

Clogged HVAC Filter

The air that circulates throughout the system is heated as it passes through your furnace or heat pump. A clogged filter can prevent air from circulating. As a result, your furnace can overheat and shut down as a safety precaution. If the fan doesn’t shut off, the system will circulate untreated cold air.

Blocked Vent or Register

If a vent is closed, you may find the heat not working, but the central air unit is running. Closed vents prevent the system from properly distributing heated air. A blocked register will restrict air intake. There'll be less air to heat and your furnace/heat pump may break down due to the strain.

Lack of Insulation

If your walls or attic aren’t properly insulated or are missing insulation, the heat produced can escape before you feel it. Therefore, rooms will feel colder despite your central unit running. Ductwork should be insulated as well to reduce heat loss

Ductwork Issue

If there’s a clog in an air duct, you may still get heat in some rooms, but not others. At the very least, dust and debris in the ductwork will reduce efficiency. Your heating bill will go up unless you have your ducts cleaned. But if ducts are torn, misaligned, or damaged, warm air can escape; your furnace may be running, but the heat may not reach your living space.

Damaged Heat Exchanger/Heating Element

The heat exchanger (in a gas furnace) or heating element (in an electric furnace) is where the magic takes place. These components are designed to last a long time. But if they do fail, the HVAC fan and blower may still run. The system just won’t produce warm air. Instead, it will waste energy while not providing the comfort you expect from it.

Faulty Fan

Your HVAC system has fans designed to blow warm air. When a fan stops working, the furnace can still run, but it will be either unable to provide heating or the heat may be inconsistent. A broken fan must be replaced, while a clogged fan can be cleaned. If not, its bearings will eventually fail, requiring replacement.

Incorrect Thermostat Setting

If your central unit is running but not producing warm air, there may be nothing wrong. Check your thermostat settings. Someone could have accidentally changed them. If the thermostat is set to cool or at a higher temperature, it won’t signal the unit to produce warm air. In this case, resetting it should fix the problem. There’s also a chance its batteries are drained and need to be replaced.

Low Refrigerant

Refrigerant is what transports heat throughout a heat pump system. In winter, it helps exchange heat into your home instead of out of it. If there’s a refrigerant leak in your house, the unit won’t stop running, but levels can drop too low for the unit to provide adequate heating.

Call Service Champions Today

When a central unit is not blowing heat, Service Champions can help with heating repairs. Our furnace and heat pump experts are licensed and extensively trained, so fix it right the first time no matter what the problem is. Financing is available for repairs, with fast and simple application and approval. We also provide a 100% satisfaction guarantee. Call 833-600-0991 for the best heating repair and maintenance service in Northern California.

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