5 Lies About Air Conditioning Many People Don’t Believe Anymore

The first really hot day of the year triggers a reflex in millions of people. As the humidity rises, you may find yourself cranking the thermostat down to 68 degrees, closing the vents in the guest room, and leaving the ceiling fans running in every corner of the house.

It sounds busy. It sounds like you’re fighting the heat – and the looming utility bill. But many of these “common sense” strategies are actually financial traps. They don’t just fail to save money; they tend to increase your energy consumption and wear out your HVAC system faster.

Here are five energy-absorbing myths you need to dispel before shower season hits full swing.

Myth: Lowering the thermostat cools your home faster

You enter a hot house. In a desperate attempt to find help, he lowers the thermostat to 60 degrees, believing that the machine will work harder and faster to reach its target.

Fact: Your air conditioner is not the gas pedal; it is a change of light. Most central AC systems operate at one speed. They are open or closed. Setting the temperature to 60 degrees produces the same amount of cool air as setting it to 74 degrees. The only difference is that the system will run continuously until it reaches that impossible target, wasting electricity long after your home is comfortable.

Fix: Set the thermostat to your actual desired temperature. If you have a variable speed unit (very rare), it works differently, but in most homes, “supercooling” is a waste of energy.

Myth: Ceiling fans cool your rooms

It seems reasonable to leave the ceiling fans running to keep the house cool while you are at work. After all, a moving air conditioner means moving air, which means lower temperatures.

Fact: Fans cool people, not rooms. They work with the cooling effect of air, evaporating moisture from your skin to make you feel cool. A fan running in an empty room does nothing to lower the actual air temperature. In fact, the engine produces less heat, which can heat up the room a bit while wasting electricity.

Fix: Treat fans like lights — turn them off when you leave the room. If you are looking for more ideas to keep your home cool, remember that using fans correctly allows you to raise your thermostat setting by about 4 degrees without reducing comfort.

Myth: Sealing off unused rooms saves money

If you don’t use the guest bedroom, why pay to cool it? Blocking the supply vents seems to be the most effective hack, diverting that precious cold air into the rooms you live in.

Fact: Your HVAC system is designed as a balanced loop. When you close the vents, you disturb the pressure balance inside the ducts. This increased pressure can force air to escape through leaks in ducts — cooling your attic or crawlspace instead of your living room — or cause the blower motor to work harder, shortening its lifespan. In modern high-efficiency systems, too many gaps can set off tripping safety coils or sensors.

Fix: Keep supply vents open to ensure proper air flow and longevity of the system. If you need to design your home, investigate professional design systems with bypass dampers rather than closing by making registers.

Myth: It is more expensive to turn the AC on and off than to leave it running

This is the most persistent myth in home cooling: the idea that your AC has to work “harder” to cool a hot house, wiping out any savings you’ve achieved by turning it on while you’re away.

Fact: The heat is getting cold. The greater the difference in temperature between the inside and outside of your home, the faster it heats up. By keeping your home cool throughout the day when it’s 90 degrees outside, your AC is constantly fighting against the rapid influx of heat. By letting the house warm, you reduce that heat transfer. There are proven ways to reduce your cooling costs, and adjusting your thermostat 7 to 10 degrees eight hours a day can save up to 10% a year.

Fix: Use a programmable or smart thermostat. Let the temperature rise while you’re at work, and schedule it to start cooling 30 minutes before you get home.

Myth: A bigger air conditioner works better

If a 3 ton unit is good, a 4 ton unit must be better, right? It will cool the house quickly and handle hot heat waves with ease.

Fact: An air conditioner that is too big is a disaster for comfort and efficiency. Because it is so powerful, it cools the air quickly and shuts down before it completes a full cycle. This “short cycling” prevents the unit from dehumidifying. You end up with a cold but cool and humid house. Regular cycling puts a lot of stress on the compressor and the fan.

Fix: Use the Manual J load calculator rather than assuming that bigger is better. A properly sized unit uses long cycles, which keep humidity low and temperatures constant.