If your aircon cools the living room but your bedroom feels like a sauna, you’re not imagining it.
This is one of the most common AC issues in Brisbane homes, especially during summer.

When one room won’t cool, the cause is almost always a restriction, leak, or imbalance in how the AC distributes air.

Here are the top 10 reasons why ONE room stays hot. Even while the rest of your home feels perfect.

1. Poor Airflow to That Room (Most Common Cause)

If your split system or ducted unit isn’t pushing enough air into that room, it will never cool.

Common causes:
✔ Blocked filters
✔ Dirty indoor coils
✔ Weak fan speed
✔ Blocked return air
✔ Vent not opening fully

If airflow feels weak, this is your issue.

2. The Room Is Simply the Hottest Room in the House

Some Brisbane rooms get cooked every summer because of:
☀ West-facing windows
☀ Large amounts of glass
☀ No shading
☀ Dark roof above it
☀ Direct sun exposure most of the day

Even a perfectly working AC will struggle if the room gains heat faster than it can remove it.

3. The AC System Is Undersized for That Room

If the AC is too small for the room size, it will:

• Cool every other room

• But struggle horribly in the largest / hottest room

Clients often add TVs, gaming PCs, extra people, and furniture, all of which increase heat load.

Rooms with:
✔ big windows
✔ high ceilings
✔ big TVs
✔ computer setups
Require stronger cooling.

4. Duct Leak or Loose Connection (Ducted Systems)

For ducted AC, one leaking duct = one useless room.

• Signs include:Warm air coming out

• Noisy airflow

• Air feels weak

• Room heats quickly again

This is VERY common in older Brisbane ducted homes.

5. Blocked or Crushed Ducting

Roof critters, insulation trades, or storage in the roof can crush ducting.

A crushed duct = near zero airflow = hot room.

6. Thermostat Is in the Wrong Location

If the thermostat is:

• in a cold passageway

• near an air vent

• in the wrong zone

It will think the whole house is cold and shut the system down prematurely.

Meanwhile, your hot room stays roasting.

7. Insulation Problems in That Room

If ONE room has:
– missing insulation
– damaged insulation
– roof gaps
– wall heat transfer
It will leak cold air and absorb heat quickly.

This is common in:
✔ older Brisbane homes
✔ extensions
✔ rooms added later
✔ garage conversions

8. Door Closed Too Often (Pressure Imbalance)

Yep, this is a real thing.

If cold air enters a room but cannot escape (door closed), the pressure builds and restricts airflow.

The AC physically cannot push more cold air in.

You’ll notice:
✔ Room cools slowly
✔ Feels humid
✔ Feels stuffy

Leaving the door open often fixes this instantly.

9. Split System Remote Sensor Not in That Room

If you’re relying on a split system in another area to cool a distant room, the AC may not detect that the hot room is hot.

It senses the temperature in the main room, not the far room.

Result:
Main area is cool = AC reduces power = distant room stays hot.

10. Electrical Issues Affecting That Room’s AC Performance

This one surprises most people.

If wiring to that room or the AC circuit has any of these issues:

• loose neutral

• voltage drop

• weak connection

• overloaded circuit

• The AC will operate at reduced performance.

Cold airflow may be weak, intermittent, or inconsistent.

Final Word: One Hot Room Is a Symptom, Not the Real Problem

When only one room won’t cool, the AC is telling you:

“Something is blocking airflow, heat load is too high, or the room is losing cold air.”

Fixing the root cause usually involves:
✔ airflow testing
✔ duct inspection
✔ system sizing
✔ insulation check
✔ sensor/damper testing
✔ electrical inspection

Need Help Fixing a Hot Room in Brisbane?

We diagnose and fix:
✔ uneven cooling
✔ one-room AC issues
✔ duct faults
✔ airflow problems
✔ system sizing
✔ sensor & electrical issues

👉 Call Exclusive Electrical & Air! Brisbane’s aircon experts.
Your home should cool evenly. Your AC should NOT play favourites.