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Why Is My Room So Hot Compared To The Rest Of The House?

You’re paddling a rickety canoe down the winding Congo River, dense tropical rainforest hemming you in on either side, and the wetness of the air swaddling you in an eternal coat of sweat. Suddenly, the air booms with the thunderous clamour of a pack of angry hippos, the biggest of which slams itself into the side of your vessel, sending you plunging into the murk…

You bolt upright in bed, and realise that once again, the roasting heat of your bedroom is affecting your dreams. All your air conditioner does is cough and splutter as it attempts to battle the oppressive humidity of the Queensland night, and it’s at this point you ask yourself “why is my room so hot compared to the rest of the house?”

In this article, we’ll explore some common reasons for an overly hot room, so that you avoid being chased by packs of furious hippos, and sleep in blissful comfort.

Why is it so hot in my bedroom?

The billions of cellular chemical reactions that help to keep us alive also happen to give off a lot of heat—roughly 100 watts of energy per hour, which is about the same as a standard lightbulb1. In the middle of the night, when you’re nestled in your doona and snoring like a truck, your body heat accumulates and pushes up your internal temperature, and if your room is already hotter than it should be, you’ll have trouble cooling down.

You can’t do anything about your body’s natural temperature, but you figure out how to cool your bedroom down. Here are some of the main reasons for a hot bedroom.

Air conditioner is the incorrect size

Whether you have a split or ducted system, if the capacity of your air conditioner is the incorrect size, it will struggle to reach the optimum sleeping temperature of 22°C. If the system is too small, it won’t have the power to reduce the temperature effectively. If the system is too large, it can operate on short and fast refrigeration cycles and fail to reduce the humidity. 

For an air conditioning system to be effective, you need the optimum system for your home. Air conditioning specialists must consider the following when installing a new system:

If these things aren’t considered, you may end up with an incorrectly-sized air conditioner, and consistently wake up in pools of sweat.

Air conditioner’s filter is clogged

Air conditioners contain filters that trap dust from the air circulating through, to prevent the unit from becoming clogged. If the filter becomes caked with dust, the machine will struggle to push air through it, and fail to regulate the temperature.

It’s recommended to clean (or replace, depending on your air conditioner) your filters every few months, to maintain the system’s efficiency.

Incorrect thermostat location

Cowboy air conditioning installers can install thermostats in the wrong location, where they’re exposed to direct sunlight or other sources of heat. Thermostats measure the temperature of the air around them, so if they’re being bombarded with heat from the sun, the blast of a kitchen’s oven, or the warmth of a hot shower, their readings won’t reflect the main living area of the home, and the system will fail to regulate the temperature.

Ducts are old or damaged

If you have a ducted system, the ducts that run through the ceiling can become damaged and leak air. They can become torn or dislodged by accident, eaten away by rodents, or filled with dust and mould. When they become damaged in this way, air circulation is worsened, and the efficiency of your system affected.

The best approach is to call in the air conditioning specialists, who can check your ducts for faults and fix them if needed.

Blocked air vents

Ducted systems circulate conditioned air through vents, and when those vents are accidentally blocked, the system will struggle to regulate the temperature. This can be a common problem in home’s with floor vents, which can accidentally be covered by furniture or rugs. 

Take a few minutes to check the vents throughout your home. They should be fully open, with nothing blocking or obscuring them.

Air conditioner needs to be serviced

It’s recommended to have your air conditioner serviced annually, by experienced technicians who know what they’re doing. If your air conditioner hasn’t been serviced in a while, you could have problems such as low refrigerant levels, dirty filters, faulty ducts, or problems with the machine itself. This can reduce the performance of the system, and the reason that your room is so hot compared to the rest of the house.

Poor insulation

Older homes tend to have lousy insulation, with cool air escaping from leaky windows, doors, roofs, walls, and floors. Your air conditioner may be correctly-sized and in top condition, but if you have poor insulation in your home, the cool air will easily escape and leave your bedroom feeling like an oven.

Check out the government’s guidelines on insulation for your home.

Sunlight exposure

If your bedroom has lots of windows and is pounded by the sun, heat can become trapped inside and push up the temperature. You can battle the sunlight by installing blinds and curtains (either standard or blackout), and keeping them closed during the day. Or for a longer-term natural solution, plant a tree or hedge on that side of the house.

Hot appliances

We live in an age of colossal 70” television screens and rows of dazzling computer monitors, which can drive up the temperature of your home, particularly your bedroom. Try to reduce your use of any hot appliances, especially the large-screen television in your room.


  1. George West, How much heat per hour do humans dissipate?, PhysLin