Why some rooms are always hotter than others

Just about every house has one — the back bedroom that never cools down, the upstairs office you cannot work in by afternoon, the room over the garage nobody uses in July. The rest of the house feels fine, so it is easy to shrug off. But uneven cooling almost always has a cause you can fix. Here is what is usually behind it, what you can check yourself, and when it is time to call.

The usual suspects

A few things cause most of the uneven rooms we see:

• A dirty air filter. It chokes airflow to the whole system, and the rooms farthest from the unit feel it first. In dusty West Texas, filters load up fast.
• Blocked or closed vents. A rug over a floor register, a couch against a supply vent, or a vent someone closed months ago and forgot.
• Long duct runs. The rooms farthest from the air handler get less air by the time it travels all that duct.
• Leaky or undersized ducts. Your ducts run through an Abilene attic that bakes in summer. A leaking or crushed duct dumps your cooled air up there instead of into the room.
• Not enough return air. The system has to pull air back as well as push it out. A room that cannot circulate well will always lag.
• Sun and windows. A west-facing room with big windows and thin insulation soaks up afternoon heat faster than the system can remove it.
• Two-story homes. Heat rises, so upstairs runs warmer to begin with.
• Thermostat placement. Your thermostat only reads the spot where it hangs. In a cool hallway, it calls the job done while a sunny room is still hot.

What you can try yourself

Before you call anyone, run through the easy stuff:

• Change the air filter, then give it a day or two.
• Open and clear every vent in the warm room — supply and return.
• Close the blinds on the sunny side during the afternoon.
• Make sure furniture or a closed door is not blocking the return-air path.

When to call Hawkins

If the basics do not solve it, the cause is usually in the ductwork or the airflow balance — and that is not a guessing game worth playing with duct tape. We will come take a look, check your airflow and ducts, and show you what we find. Depending on the cause, the fix might be sealing or repairing ducts, adding a return, balancing the airflow between rooms, adding zoning so different areas run on their own settings, or dealing with a system that is short-cycling. See our AC repair and indoor air quality services — and a maintenance plan keeps airflow problems from creeping back.