Does Changing the Thermostat Save Money? Tips for Lower Energy Bills

For homeowners and business owners, energy costs are always top of mind, especially during extreme Illinois weather. At Mendel Plumbing and Heating, a common question we hear alongside requests for Illinois air conditioning services is whether adjusting your thermostat actually saves money.

The answer is yes, but it depends on how you use it. HVAC energy use largely comes down to runtime, and your thermostat controls how often your system runs to maintain a set temperature. The longer it runs, the more energy it uses. Keep reading to learn more. 

Best Thermostat Strategies by Season That Actually Reduce Bills

Here’s a simple, practical way to apply thermostat setbacks throughout the year, using proven guidelines while keeping comfort front and center.

Winter (Heating Season):

• Baseline setting: Aim for about 68°F when home and awake.
• Setback strategy: Lower the temperature overnight or during work hours if comfortable.
• Minimum viable plan: Reduce the setpoint by 7 to 10 degrees for about 8 hours, such as while sleeping or away.
• Comfort and safety tips: Avoid setting temperatures so low that living spaces become uncomfortable or increase the risk of frozen pipes, especially near exterior walls or poorly insulated areas.

Summer (Cooling Season):

• Baseline setting: Aim for about 78°F when at home.
• Setback strategy: Raise the temperature when you are away or asleep if it remains comfortable.
• Minimum viable plan: Increase the setpoint by 7 to 10 degrees for about 8 hours during the day or overnight.
• Comfort and humidity tips: Higher temperatures can still feel comfortable if humidity is controlled, but some homes may need additional dehumidification to maintain comfort.

How this looks in real life:

• 9 to 5 household: Adjust temperatures during work hours and overnight to reduce system runtime when no one is home.
• Work from home household: Use smaller daytime adjustments but still take advantage of overnight setbacks.
• Frequent travel: Apply larger setbacks while away for extended periods.
• Families with kids or the elderly: Prioritize comfort with more moderate changes that still reduce unnecessary energy use.

Manual vs. Programmable vs. Smart Thermostats: Which Helps You Save?

Choosing the right thermostat can make a difference in how effectively you manage energy use, but the biggest factor is how you use it. Whether you have a manual, programmable, or smart thermostat, each option can help reduce HVAC runtime and improve efficiency when used correctly.

Manual Thermostats

Manual thermostats can help you save money, but they rely entirely on consistent behavior. To see results, you need to remember to adjust the temperature throughout the day, such as lowering it before leaving for work or raising it before bed. For many households, the easiest approach is to build a simple daily routine around these changes. The challenge is that it is easy to forget, and missed adjustments can lead to unnecessary system runtime.

Programmable Thermostats

Programmable thermostats take the guesswork out of daily adjustments by letting you set a schedule in advance. This helps reduce wasted runtime by automatically adjusting temperatures when you are asleep or away, without relying on memory.

The advantage is consistency. Once properly set up, the thermostat maintains energy-saving setbacks every day. However, a common issue is that many homeowners never fully program their thermostat or create overly complicated schedules that end up being ignored.

Smart Thermostats

Smart thermostats go a step further by adding features like learning your schedule, detecting occupancy, and allowing remote control through your phone. Some models can automatically adjust settings based on your habits or optimize runtime for efficiency. These features can lead to energy savings, but only if the thermostat is set up correctly and used as intended.

ENERGY STAR-certified smart thermostats are evaluated using real-world performance data to ensure they reduce HVAC runtime, though actual savings still vary by home. It is also important to avoid common setup issues, such as incorrect heat pump settings, which can reduce efficiency if not configured properly.

When Changing the Thermostat Doesn’t Help

Adjusting your thermostat can be an effective way to reduce energy use, but it does not always lead to noticeable savings in every home. In some cases, underlying issues or system differences can limit the impact. Homes with poor insulation or air leaks can lose heated or cooled air so quickly that temperature changes have less effect. Older or inefficient HVAC systems may also run longer regardless of setbacks, reducing potential savings.

Frequent or extreme thermostat changes can work against you as well. Constant adjustments throughout the day can increase system runtime, add unnecessary wear and can even cause power surges. Heat pumps behave differently from traditional furnaces or boilers, and large setbacks can trigger less efficient backup heating, which may cancel out savings. The best approach is steady, intentional adjustments paired with a well-functioning system.

If your energy bills are still high despite using good thermostat settings, it is worth doing a quick check of the basics:

• Air filter condition: Dirty filters restrict airflow and make your system work harder.
• Equipment maintenance: Lack of regular service can reduce efficiency and performance.
• Duct issues: Leaks or poor design can waste heated or cooled air before it reaches your space.
• Insulation and air sealing: Gaps and weak insulation allow energy to escape, increasing runtime.

A Practical Thermostat Savings Checklist

If you want to start saving without overthinking it, keep things simple. Choose a baseline setpoint for the season, around 68°F in winter and 78°F in summer, then add one consistent setback period each day, such as while you sleep or are away. Aim to hold that change for about 8 hours, so it makes a difference. From there, focus on comfort first and adjust in small 1-to-2-degree increments over the course of a week until you find the right balance.

It is also worth doing a few quick sanity checks:

• Thermostat placement: Make sure it is not in direct sunlight or near drafts that can affect readings.
• Air filter condition: Replace filters regularly to prevent restricted airflow and excess runtime.
• System performance: Watch for short cycling, uneven temperatures, or unusually long runtimes.
• Ease of use: If you forget to adjust settings, consider a programmable or smart thermostat that is properly set up.

If results are not improving, consider a professional evaluation from Mendel Plumbing and Heating, including heating repair and installation in Illinois' Fox Valley area, seasonal maintenance, thermostat setup, or diagnosing comfort issues.