05/13/2025
🔥 HVAC tip of the week 🔥
During the hottest parts of summer in Minnesota, typically from 1 PM to 7 PM, an air conditioner (AC) runs for about 15–20 minutes per hour to maintain a set indoor temperature. Over this 6-hour period, this totals around 1–1.5 hours of runtime, depending on factors like outdoor temperature, home insulation, AC efficiency, and humidity levels.
Many people believe that turning off their AC or raising the thermostat significantly while away saves money on their electric bill. However, this is often a misconception, especially in humid climates like Minnesota.
Maintaining a consistent temperature, or keeping the thermostat within 3–6°F of your desired temperature, allows the AC to operate under a lighter load, using fewer amps (less electricity) to cool your home and control humidity.
When you turn off the AC or set the thermostat much higher, the indoor temperature and humidity can rise significantly—sometimes by 10–15°F or more, with humidity levels exceeding 60%. When you return home and lower the thermostat, the AC is forced to work much harder to remove heat and humidity. The compressor runs continuously under a heavier load, consuming more electricity and often running for 2–3 hours or longer to reach your desired temperature. This extended runtime can negate or exceed any energy savings from turning the AC off. 🤑
Moreover, letting humidity build up in your home has additional consequences beyond energy costs. High humidity (above 60%) can damage woodwork and compromise indoor air quality.😳
Excess humidity causes wood in furniture, flooring, and cabinetry to absorb moisture, leading to swelling, warping, or cracking. For example, hardwood floors may buckle or develop gaps, and wooden furniture joints can weaken over time. In Minnesota’s humid summers, long periods of high indoor humidity exacerbate these issues, potentially leading to serious damage over time and costly future repairs.
High humidity also promotes mold and mildew growth, especially in basements, bathrooms, or poorly ventilated areas. Mold spores can degrade indoor air quality, triggering allergies, asthma, or respiratory issues. Dust mites, which thrive in humid environments, also multiply, further worsening air quality. 🤧
An AC maintaining a consistent temperature helps dehumidify the air, keeping indoor humidity between 35–45%, which is ideal for comfort and health.
While small thermostat setbacks (3-6°F) can save energy in some cases, they work best in well-insulated homes or drier climates where humidity buildup is minimal. In Minnesota, where summer humidity is high, turning off the AC or using extreme setbacks often leads to higher energy use and risks to your home’s woodwork and air quality.
Maintaining a consistent indoor temperature, or using modest thermostat setbacks of 3–6°F is typically more energy-efficient than turning off your AC or setting it much higher while away. This approach also protects your home’s woodwork from moisture damage and maintains healthy indoor air quality by controlling humidity. For the most savings, consider using a programmable thermostat to automate small setbacks and ensure your AC is properly maintained by HVAC wizards for optimal efficiency 🧙♂️
