School is back in session across Washington County, which means that from about 8 a.m. to 3 p.m. on weekdays, your house is empty.
Your thermostat doesn’t know that.
Most people are still running the settings they set back in June, when the house was full, the fridge door opened every eleven minutes, and somebody was always leaving the back slider open. We’ve got a few more weeks of triple digits ahead, so your AC isn’t off the hook yet. But the way your household uses the house changed overnight, and how you cool it should change with it.
Stop cooling an empty house
This is the biggest one, and it costs nothing.
If nobody’s home until midafternoon, there’s no reason to hold 74 degrees for the benefit of your furniture. Raise the setpoint five to eight degrees during the empty hours, then have the system start pulling the house back down about 30 to 45 minutes before the first kid walks in. Done right, you never feel it. You just stop paying to cool rooms nobody’s standing in during the most expensive stretch of the day.
One caution on how far to push it. Letting the house drift up to 85 sounds efficient until your system spends two hours in a hard recovery cycle every afternoon at peak heat. That’s rough on a compressor that’s been running since May, and it can eat most of what you saved. Moderate beats aggressive here.
Two other things worth setting up while you’re in the thermostat menu. Build a separate weekend program, because a Saturday morning running the weekday schedule is its own special misery. And if you’ve got pets home during the day, set a reasonable ceiling. Dogs don’t need 72, but they need better than what an unconditioned house in St. George gets to by two in the afternoon.
Smart thermostat? Geofencing does all of this on its own, and lets you override from the parking lot at practice.
September and October are stranger than people expect
Our shoulder season does something odd to energy bills. You can need cooling at 4 p.m. and heat at 6 a.m. on the same day. A 40-degree daily swing is normal here in October, and a thermostat set to hold a narrow temperature will chase that swing all day long, running the AC and the furnace within a few hours of each other.
So widen the band. Set cooling to kick on at 78 and heating at 68. Everything in between is free, because the system simply doesn’t run. It’s the easiest change on this list and the one almost nobody makes.
Once overnight lows drop into the 60s, open the house in the evening and shut it up by eight in the morning. That’s free cooling. And when you eventually flip over to heat, reverse your ceiling fans to clockwise on low so they pull warm air down off the ceiling instead of blowing a draft at you. Nobody remembers this one. Set a reminder for late October.
Your AC just finished a marathon
It’s been running close to nonstop since May. In a Southern Utah summer that’s a punishing duty cycle, and it leaves evidence behind. We pull filters in September that look like somebody used them to strain gravel.
Late summer is a good time to take a look, and the practical reason is timing. Whatever you find now gets handled on a normal schedule at a normal price, instead of as an emergency call on the next 108-degree afternoon.
What you can check on your own: •- The filter. If it hasn’t been changed since early summer, it’s worse than you’re picturing.
- The outdoor unit. Pull the weeds, trim anything within two feet of it, and rinse the coil fins with a hose on low pressure. Our dust and cottonwood are hard on condensers.
- Your vents. Summer furniture shuffling has a way of parking a couch in front of a return.
- Anything new. Rattles, longer run times, a system that can’t quite reach setpoint by late afternoon. Those are worth a call now rather than in October.
One more thing. On the first cool morning we get, run the furnace for ten minutes. It’ll smell like burning dust, which is normal and goes away. What you’re listening for is anything that isn’t. Much better to find out in September than on the first cold night.
The small stuff adds up
Close the blinds on west-facing windows after about two o’clock, because afternoon sun through unshaded glass out here is a space heater you didn’t ask for. Run the dishwasher and the dryer after eight at night so you’re not dumping waste heat into the house at the exact hour your AC is working hardest. Use the bathroom and kitchen exhaust fans instead of asking the AC to pull that heat and moisture out after the fact. And if there’s one room that’s always warm at four in the afternoon, that’s usually not just a bad room. It’s a duct balancing or insulation issue, and it’s worth mentioning next time somebody’s out.
Get ahead of it
The back-to-school reset is as good an excuse as any to look at how your system actually runs, before you spend another month paying for a routine your household stopped keeping in May.
Maverick Air Conditioning works with homeowners in St. George, Washington, Hurricane, Ivins, and across Southern Utah. If your system struggled this summer, or your bills came in higher than they should have, a fall tune-up is the place to start.