10 Common A/C Mistakes That Cost You Money

When it comes to beating the summertime heat, your air conditioner is a lifeline. However, if you don’t use your cooling system correctly, you could see a spike in your energy bills—or worse, a decrease in the lifespan of your equipment. At Main Stream Mechanical, we want to keep your home comfortable and efficient. Here are 10 common A/C mistakes to avoid and what you can do instead.

1. Not Replacing Your Air Filter 

Dirty air filters restrict airflow, forcing your A/C to work harder and adding unnecessary stress to your system. We recommend replacing your air filter every three months. This is especially important for homeowners with allergies and those trying to control pet hair and dander. 

2. Ignoring Regular Maintenance

Annual maintenance is essential. A professional tune-up keeps your system running at peak performance and catches minor issues before they require major repairs. NOTE: Your AC manufacturer may require annual AC maintenance to maintain your warranty.

3. Leaving Windows or Doors Open

Always ensure that windows and doors are fully closed when the A/C is on. Even a small crack in a window or door can let in warm air and allow cool air to escape, causing your system to cycle more frequently.

 4. Cranking the Thermostat Way Down

Lowering your thermostat to 60°F won't cool your house faster—it just makes your system run longer and waste energy. Instead, aim for a comfortable setting like 74–76°F and be patient.

5. Cooling an Empty House

Running the A/C at full blast when no one’s home is a costly habit. Install a programmable or smart thermostat to automatically adjust the temperature when you're away from home.

6. Blocking Vents with Furniture or Curtains

When it comes to air conditioning, airflow is everything. Rearrange your furniture and curtains to ensure your vents are not blocked. 

7. Forgetting About Your Ceiling Fans

Since ceiling fans help circulate cool air more efficiently, they can reduce your energy costs. Turn your ceiling fan on in a counterclockwise direction, and you’ll be able to raise your thermostat a few degrees without sacrificing comfort. 

8. Not Sealing Leaks

Use weather stripping or caulking to seal any gaps or cracks around your doors, windows, or ductwork. This will prevent cool air from escaping, improving the efficiency of your cooling system and reducing your energy costs.

9. Overusing Heat-Generating Appliances

Stoves, ovens, and even some lighting can increase your indoor temperature, causing your A/C to work overtime. Try cooking during cooler hours or switching to small appliances like toaster ovens or microwaves.

10. Installing the Wrong-Sized A/C System

When it comes to AC systems, size matters A LOT.  An oversized AC unit may quickly cool your home, but it won’t remove humidity properly, leading to clammy air, while an undersized system will struggle to keep up. By conducting a professional load calculation, our cooling experts will correctly size your AC system for your home.

AC Installation, Service, and Repair in MA and Southern NH 

Need help keeping your cooling system running efficiently? Our licensed HVAC experts are here to help with AC maintenance, repairs, or energy-saving upgrades. Contact Main Stream Mechanical at (978) 834-0849 or visit us online to schedule your service appointment.