The Best Temperature to Set Your Thermostat in May for Spring Comfort and Energy Affordability
HVAC experts say you don’t have to pay sky-high AC bills to stay cool this spring
Balancing the comfort of a cool home with the rise in energy costs can be challenging in late spring, with fluctuating temperatures and seasonal weather phenomena at play.
That’s why I spoke to HVAC experts to find out the best temperature to run your thermostat as we move towards the increasing heat and humidity of May, so that you can maintain an ideal environment at home without unsustainably raising your AC costs.
Article continues belowWhy May Home Cooling Is So Tricky In Many Parts of the US
If you're running your trusty oscillating tower fan, such as the Dreo, available at Walmart, but increasingly having to switch on the AC in the last few weeks, you're not alone.
Gary McCurry, HVAC Service Director at Reliable Heating and Air, explains the common seasonal cooling challenges of balancing comfort and cost.
He advises, 'If I had to give one simple spring rule, it would be this: Set it as high as you can while still feeling comfortable, because every degree lower makes your system work harder and costs more.’
Gary says for most homeowners, a good May thermostat baseline is 72 to 74° Fahrenheit when you’re home, then adjust slightly based on humidity, shade, insulation, and personal comfort.
There are many ways to keep your energy costs low, including using a Smart thermostat such as the highly-rated, Wi-Fi compatible Copeland Sensi from Lowe’s, so that your system cycles on and off to maintain a set temperature, rather than running non-stop.
Running yours nonstop can also result in you feeling too cold at home, switching off the AC, and your whole home’s temperature rising, and the cycle repeating. It takes far more energy to re-cool an entire house than it does for a smart thermostat to maintain a steady temperature with shorter cycles.
Gary’s recommendations for the optimum home temperature control in May are:
- If you’re home during the day: 72-74°F
- When sleeping: 70 to 72°F
- Away for a few hours: 76 to 78°F
- Away longer: you can go a little higher, but do not shut the system off completely in humid climates.
Be Mindful of Humidity
Gary adds that May is particularly tricky in many parts of the US as it is warm enough to need cooling, but has not yet reached the full, intense heat of midsummer.
He says, ‘A setting in the low-to-mid 70s usually strikes the best balance between comfort and affordability. It keeps the house cool enough to manage late spring heat and humidity without overcooling the space or driving up utility bills unnecessarily.’
Your home's humidity is a key factor too, as the extra moisture in the air makes it harder for your body to sweat, which is the key cooling mechanism evolution has rewarded humans with.
An affordable set of hygrometers available at Walmart will help you monitor levels. Too much moisture may indicate a failure in draftproofing your home. This quality of your window and door seals, as well as around your attic hatch, will be pivotal in keeping your cooled AC air inside, rather than it leaking out, and reducing your bills by up to 15%. You can also reduce that humidity by running your AC or an energy-efficient dehumidifier, available at Amazon.
HVAC expert Gary adds, ‘In spring and early summer, people often think they need a much lower temperature, when what they are really feeling is excess humidity. If your system is working properly, a moderate thermostat setting can still feel comfortable because the AC is helping remove moisture from the air.
‘The lower you set the thermostat, the longer and harder your air conditioner runs. That means higher energy use and more wear on the system. Keeping the thermostat in that 72 to 74°F range in May can help homeowners stay comfortable without forcing the system to run like it is July or August.
Keeping Your Bills Low While Managing Late Spring Temperatures
Jimmy Campbell, HAC expert at Townsend Total Energy, explains, ‘Maintaining the highest possible comfortable temperature helps keep your AC bills affordable. For example, if you can maintain 70 72°F without your system running constantly, you save roughly 3% per degree, per day.’
He adds that in July, when it's mid-summer and 90°F and hotter, maintaining 68°F indoors is harder.
Jimmy says, ‘The difference between the outdoor and indoor temperature is greater, so your system will have to work harder and longer. In that kind of heat, your home will naturally absorb the outdoor temperature, so accepting a slightly warmer indoor temperature will help you save money.
'Instead of 68°F, aim for 70°F. These indoor temperatures will feel much cooler than the 90°F (or higher) temperatures outside. If you have ceiling fans, keep them on. This will help you feel roughly 5° cooler. Also, keep the blinds closed on windows that face the sun to block out the unwanted heat.'
You should also reverse your fan direction in the summer so they run counter-clockwise. Our HVAC experts have previously told Homes & Gardens that doing this will push cool air down, producing a wind chill that can make a room feel up to eight degrees colder.
How to Avoid Straining Your AC System
It’s a common misconception that AC systems cool ‘faster’ just because you set the thermostat lower. ‘That just means the system will be running longer and costing you more money,’ Jimmy warns. ‘Find your range of comfort and maintain it. You don't need to run your AC 24/7.
‘If your nighttime temperatures dip below your desired indoor temperature, throw the windows open and enjoy the cool air for free.'
Doing this after rain and sudden spring showers will reduce the impact of pollen, too, and it's known as the rain cooling method.
He adds, 'In July, when it's hot even at night and humid, you can keep the AC on, but set it a little warmer while you sleep. 74–76°F is usually a good range for when you are away or sleeping.’
How AC Systems in 2026 Compare to Decades Ago
Over the last few decades, HVAC equipment has improved significantly. Today's standard HVAC systems run at 14-16 SEER ratings (the higher the number, the more cooling you get for every dollar spent on your electric bill) with top-tier units reaching up to 20.
‘15 or 20 years ago, that wasn't the case at all,’ Jimmy adds. ‘Most systems had ratings of 6-8. Programmable and smart thermostats also make a huge difference now. 20 years ago, most homes had basic analog thermostats that you had to adjust constantly.’
Of course, climate change and hotter summers are making an impact on what it takes to keep your home comfortable year-round, whilst at the same time, building materials, regulations, and user needs have changed.
‘Homes that were built in the 90s generally didn't have central AC,’ Jimmy says, ‘because it wasn't needed. Now, cooling systems are more widely needed.’
It’s why in the winter, the old heating standard is out, and new rules have come in to account for the leap in technology and insulation.
What to Shop
Keeping comfortable in rising temperatures is an ongoing challenge that often needs to be balanced with rising costs. Tackling air movement, humidity, and cooling together, alongside sealing gaps that may have appeared over winter from thermal change, provides a robust strategy for comfort without excessive energy costs.
Here are the essentials to keep your household cool and comfortable as we move towards May and warmer temperatures still.
All prices were correct at the time of publication.
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Meet the Experts
Gary McCurry leads service operations across one of the largest and most trusted home service providers in the Southeast. With extensive experience in HVAC service and operations, Gary specializes in delivering consistent, high-quality customer experiences at scale. Gary is passionate about improving operational efficiency and helping homeowners get the most out of their heating and cooling systems through proper maintenance, performance, and education.
Jimmy Campbell is a residential HVAC expert with 10 years of hands-on industry experience, including five years as a trusted technician at Townsend. Specializing in service, oil and propane systems, and air conditioning, Jimmy has deep technical knowledge and practical expertise working in residential homes. He understands the real-world heating and cooling challenges homeowners face, from routine issues to complex system failures. His specialized background in oil and propane systems lends particular expertise in heating fuel alternatives, energy efficiency, and the evolving landscape of residential climate control.
Learn how to cool a room with fans, and sleep better with the latest and best cooling mattress toppers and pads. Having some of the best bed sheets that are moisture-wicking will also help keep you comfortable in spring.
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