What’s the Ideal AC Temperature Setting in Ontario Homes?

Ontario summers can go from pleasantly warm to sweltering fast, leaving many homeowners wondering what temperature to set their air conditioner at. Striking the right balance between comfort, energy efficiency, and cost savings can make all the difference, especially during peak electricity hours. 

So, what’s the ideal AC temperature for Ontario homes? 

Recommended AC Temperature for Comfort and Efficiency 

Most energy experts, including Natural Resources Canada, recommend setting your air conditioner to 25°C (77°F) when you're at home and awake. This temperature keeps you cool without overworking your AC unit, especially during humid Ontario summers. 

When you’re away from home or asleep, raising the temperature by a few degrees up to 28°C (82°F) can help save on energy bills without compromising comfort. These small changes can lead to significant savings over the course of the summer. 

Why 25°C Works Well in Ontario? 

Setting your thermostat to 25°C: 

• Keeps indoor humidity at a manageable level 
• Reduces the chance of your system short cycling or freezing up 
• Supports the lifespan of your AC unit 
• Helps avoid overloading your electrical panel during heatwaves 

If your AC is consistently running but your home isn’t cooling effectively, it might be a sign of poor insulation, an undersized unit, or clogged filters.  

Smart Thermostat Settings for Maximum Control 

If you have a smart thermostat, consider setting temperature schedules based on your daily routine: 

• Morning: 25°C as you wake up and get ready 
• Afternoon: 26–28°C if the house is empty 
• Evening: 24–25°C for comfort while you're home 
• Night: 26°C while you sleep to avoid overcooling 

This approach can reduce strain on your AC and lower hydro costs during Time-of-Use pricing hours in Ontario. 

Factors That Impact Ideal Temperature 

Your ideal AC setting may also depend on: 

Home Insulation Quality 

Poor insulation allows cool air to escape, forcing your AC to work harder. Sealing drafts around windows, doors, and attics can help maintain temperature more efficiently. 

Age and Size of Your AC Unit 

An older or undersized AC system may not be able to keep up with your cooling needs. If your unit is constantly running without making the room cooler, it may be time to explore an upgrade. Learn more in How Hybrid AC Systems Save You Money Year-Round. 

Ceiling Height and Window Exposure 

Homes with high ceilings or large south-facing windows heat up faster, requiring a more powerful cooling system or smart zoning. Installing blinds or UV film on windows can help minimize heat gain. 

Personal Comfort Preference 

Some people naturally prefer cooler environments, especially at night. Using ceiling fans and localized cooling can help you feel comfortable at a higher thermostat setting. 

If you’re constantly adjusting the thermostat and still not comfortable, it may be time for an AC inspection or upgrade. Explore our range of energy-efficient air conditioners designed for Ontario climates. 

Tips to Stay Cool Without Lowering the Thermostat 

• Use ceiling fans to circulate cool air 
• Keep curtains and blinds closed during peak sunlight 
• Seal gaps around windows and doors 
• Schedule regular AC maintenance to ensure top performance 

When Your AC Temperature Isn't Working as Expected 

If your thermostat is set properly but your home still feels warm, possible causes include: 

Dirty Air Filters 

Clogged filters restrict airflow, causing your AC to work harder and cool less effectively. In Ontario’s pollen-heavy summers, filters can clog faster than expected.

Read: How Often Should You Change Your AC Filter in Ontario? 

Low Refrigerant Levels 

Low refrigerant reduces your system’s ability to remove heat and humidity. It can also lead to frozen coils or water leaks. If you suspect this, check out Why Is My Air Conditioner Leaking Water? 

Electrical Issues or Weak Airflow 

Loose wires, failing capacitors, or faulty thermostats can lead to inconsistent cooling. In some cases, your breaker may trip to prevent damage. Learn what to watch for in Why Does My Air Conditioner Keep Tripping the Breaker? 

If your airflow feels weak even with clean filters, your system may be oversized or your ducts may need sealing. For full troubleshooting, explore How to Troubleshoot the Most Common Summer AC Problems in Ontario 

Ductless vs Central Air: Which Maintains Temperature Better? 

If you're frequently adjusting the thermostat and still feel uncomfortable, your current setup may not be ideal. Ductless vs Central Air Conditioning systems offer different strengths when it comes to zoned cooling and overall control. 

Final Thoughts 

The ideal AC temperature in Ontario is generally 25°C for comfort and up to 28°C for savings. Adjust based on your routine, use a programmable thermostat, and keep your system well maintained. 

If your home isn’t staying cool no matter what you set the thermostat to, it might be time for a tune-up or even a system upgrade. Go Lime offers expert cooling services across Ontario, including same-day installation, repair, and energy-efficient system upgrades. 

Book your free consultation here today and stay cool with confidence.