A smart thermostat is one of the few upgrades that can pay you back every single month, but only if it is set up to match how you actually live. We see plenty of Durham Region homes where a capable thermostat is essentially being used like the old dial on the wall — and the savings it promised never show up. The good news is that dialing in the right smart thermostat summer settings takes about ten minutes.
Here is how we coach homeowners to get real cooling savings out of theirs without ending up uncomfortable on the hottest July afternoons.
Start With a Sensible Base Temperature
Comfort is personal, but most households find a summer setpoint around 24 to 25 degrees Celsius comfortable while you are home and active. Every degree you raise the setpoint reduces the runtime your air conditioner needs, and in a humid Ontario summer those degrees add up quickly over a billing cycle.
The trick is not to crank the temperature far lower than you need the moment you walk in. An air conditioner cannot cool a house faster by being set to an extreme number; it simply runs longer to reach that point. A steady, reasonable setpoint almost always beats big swings.
Let the Schedule Do the Work When You Are Away
The single biggest source of waste is cooling an empty house to the same temperature you would want while relaxing on the couch. Set the thermostat to drift a few degrees warmer — say up to 27 or 28 degrees — during the hours nobody is home, then return to your comfort setpoint shortly before you arrive back.
Most smart thermostats handle this automatically through a schedule, and many add geofencing that uses your phone’s location to adjust when the house is genuinely empty. That matters in households with irregular schedules, where a fixed timetable would either waste energy or leave you walking into a warm home.
Use Fan “Auto,” Not “On”
This small setting trips up a lot of people. Leaving the fan set to on runs the blower continuously, even when the system is not actively cooling. In a humid climate that can actually re-evaporate moisture off the coil and push it back into your home, making the air feel stickier. Set the fan to auto so it runs only during cooling cycles, which helps your system remove humidity properly.
Let It Learn, and Pair It With a Healthy System
Learning thermostats get better over a couple of weeks as they map your patterns, so resist the urge to override them constantly — every manual override teaches the device that its schedule is wrong. Eco or adaptive modes are usually worth leaving on.
A thermostat can only manage the equipment it is connected to, though. If your air conditioner is low on refrigerant or overdue for service, no setting will deliver the comfort or the savings you are after. We usually recommend pairing a smart thermostat with a yearly tune-up through a maintenance plan so the whole system performs as designed. When it is time to choose a new thermostat, certified models listed through ENERGY STAR Canada are independently verified to deliver real efficiency gains.
When to Ask Us for a Hand
If your smart thermostat is not holding a schedule, your rooms cool unevenly, or your bills are climbing despite careful settings, the issue may be with the wiring, the system sizing, or the equipment itself rather than the thermostat. Our air conditioning team can check the whole picture and make sure your thermostat and your AC are actually working together.
Use Pre-Cooling Instead of Big Mid-Day Swings
If your home heats up badly in the late afternoon, let the thermostat pre-cool slightly before the peak rather than asking the system to claw back several degrees during the hottest part of the day. Bringing the home to your comfort setpoint a little early, then letting it coast, is gentler on the equipment and avoids the long, hard run that a mid-afternoon recovery demands. Most smart thermostats can be scheduled to do exactly this once you know your home’s daily heat pattern.
Add Remote Sensors for Multi-Room Homes
A thermostat only measures the temperature where it is mounted, which is usually a hallway. If your bedrooms run warmer than that hallway, the system will think the house is comfortable while you are anything but. Many smart thermostats support remote room sensors that let the system average several rooms or prioritize the room you are actually using — a bedroom overnight, for example. In a two-storey Durham home where the upstairs always lags, this single feature often does more for comfort than any temperature change.
Set a Comfortable Overnight Strategy
Overnight is a chance to save without noticing it. Many people sleep comfortably at a slightly warmer setting than they would want during the day, and outdoor temperatures drop after dark, so the system works less to hold a setpoint. A modest overnight setback — or a gentle pre-dawn adjustment so the house is comfortable when you wake — trims runtime during hours you are not awake to feel it. If anyone in the home is sensitive to heat overnight, keep the change small and let comfort win.
Watch the Humidity, Not Just the Number
On a sticky July day the temperature can read fine while the air still feels heavy. Some smart thermostats display indoor humidity, and a few can call for slightly longer cooling cycles when humidity is high to help dry the air. If yours shows humidity, aim to keep it in a comfortable range rather than fixating only on the temperature — you will often find you are comfortable at a higher setpoint once the moisture is under control, which saves energy on top of the comfort gain.
Frequently Asked Questions
What temperature should I set my thermostat to in summer?
Around 24 to 25 degrees Celsius while you are home is a comfortable, efficient starting point for most households. Let it rise a few degrees while you are away and adjust to your own comfort from there.
Does setting the temperature very low cool the house faster?
No. The system cools at the same rate regardless of the setpoint; a very low setting just makes it run longer and use more energy. A steady, moderate setpoint is more efficient.
Is a smart thermostat worth it if my AC is old?
It can still help, but an aging or poorly maintained system limits the savings. Pairing the thermostat with a tune-up — or planning ahead for a replacement — gets you the full benefit.
Should I turn the AC off completely when I leave for the day?
For a normal workday absence it is usually better to let the temperature drift a few degrees warmer rather than switch the system off entirely. Turning it off completely lets the house — and its humidity — climb so high that the air conditioner has to work hard to recover when you return, which can cost more than the modest setback would have. For longer absences of several days, a larger setback makes good sense.
Talk With Fortis Heating & Air Conditioning
If you are in Oshawa, Whitby, Ajax, Clarington, or anywhere across Durham Region and something about your cooling system does not feel right, we are happy to take a look. Call (289) 688-4822 or reach us through our contact page, and our team will help you sort out the next step at a pace that makes sense for your home.
