Adjusting your thermostat can significantly impact your energy consumption and utility bills. Temperature setbacks—the practice of changing your thermostat settings while you’re asleep or away from home—can lead to substantial savings on your heating and cooling costs.
Above, Ask This Old House plumbing and heating expert Richard Trethewey explains how setbacks work and their potential for saving energy. Here’s what you need to know to set your thermostat for significant energy savings without sacrificing comfort.
What Is a Thermostat Setback?
A thermostat setback is the practice of adjusting your thermostat to use less energy during certain times, such as when you’re sleeping or away from home. In winter, this typically means lowering the temperature. In summer, you would raise it.
How Do Setbacks Work?
Setbacks help save energy by reducing the temperature difference between the inside and outside of your home. This difference, known as the delta T, affects how hard your heating or cooling system works. By reducing this gap, you lower the amount of heat transfer, which means the system needs less energy to maintain your home’s temperature.
Types of Thermostats for Setbacks
The type of thermostat you have will determine the amount of effort the setback process will require on your part:
- Manual thermostats: Require you to adjust the temperature manually each time you want to implement a setback.
- Programmable thermostats: Allow you to set schedules for temperature changes throughout the day and week.
- Smart thermostats: Learn your habits and can automatically adjust temperatures based on your routines or even your location.
The Benefits of Thermostat Setbacks
Thermostat setbacks offer several advantages, especially when it comes to saving energy and reducing utility bills.
Energy Savings
The Department of Energy estimates that for every degree you lower your thermostat for 8 hours, you can save about 1% on your heating bill. So, dropping your thermostat by 10 degrees for 8 hours a day could lead to around 10% savings annually.
While the exact savings depend on factors like your climate, home insulation, and local energy prices, most homeowners will see noticeable reductions in their heating and cooling costs.
Environmental Impact
By using less energy, you’re also conserving resources and reducing your carbon footprint. This makes thermostat setbacks an easy way to make your home more environmentally friendly without major renovations or investments.
Implementing Effective Setback Strategies
To maximize the benefits of thermostat setbacks, it’s important to implement them correctly. Here are some strategies to help you get the most out of your setbacks.
Optimal Setback Temperatures
For winter setbacks, the Department of Energy recommends setting your thermostat to 68 degrees Fahrenheit when you’re awake and lowering it by 7–10 degrees when you’re asleep or away. In spring and summer, they suggest setting the thermostat to 78 degrees Fahrenheit when you’re home and raising it by 7–10 degrees when you’re away.
Timing Your Setbacks
The most effective times for setbacks are typically:
- While you’re sleeping (for example, 11 p.m.–6 a.m.)
- When you’re away at work (usually 9 a.m.–5 p.m.)
- During vacations or extended absences
Using Programmable and Smart Thermostats
Programmable and smart thermostats can handle temperature adjustments automatically, so you never have to worry about forgetting to adjust the thermostat. Smart thermostats can even learn your habits and make the right changes for you.
Common Misconceptions About Setbacks
Despite their effectiveness, there are some persistent myths about thermostat setbacks that can discourage homeowners from implementing them.
Myth: It Takes More Energy to Reheat
One common misconception is that it takes more energy to reheat a home than to maintain a constant temperature. However, as Trethewey explains, the energy required to reheat your home will always be less than what you save during the setback period.
Myth: Extreme Setbacks Are More Effective
The 1% savings guideline isn’t infinite. While setbacks do save energy, setting your thermostat to extreme temperatures won’t necessarily save you more money. This is because efficient HVAC use actually prevents other home problems. For example, very low temperatures in winter can lead to frozen pipes, while very high temperatures in summer can cause humidity issues.
Myth: Setbacks Don’t Work in All Climates
Some people believe that setbacks are only effective in moderate climates. In reality, setbacks can provide savings in most climates, though the optimal setback temperatures may vary based on your local weather patterns. Remember that even small setbacks can have noticeable effects.
When Not To Use Thermostat Setbacks
While setbacks are generally beneficial, there are some situations where they may not be appropriate or effective.
Heat Pump Systems
Some heating systems are more sensitive to setbacks. Electric heat pump systems, especially those with electric resistance heating as a backup, may not be ideal for thermostat setbacks. These systems can be less efficient when trying to recover from significant temperature changes, leading to higher energy use during the recovery phase.
Super-Insulated Homes
Highly insulated homes already retain heat (or cool air) very efficiently. In these cases, the energy savings from setbacks might be minimal and not worth the potential discomfort of temperature fluctuations. When a home is well-insulated, the natural rate of temperature loss is slow, so the benefits of a setback are lower.
Radiant Heating Systems
Homes with radiant floor heating, especially those with concrete slabs, may not benefit from setbacks. These systems take longer to adjust temperatures, making frequent changes less effective. Radiant heating relies on the slow and steady radiation of heat, so drastic temperature changes can disrupt the system’s efficiency. Frequent adjustments can also lead to uncomfortable periods of waiting for the system to catch up.
Comparing Thermostat Setback Strategies
Different setback strategies may offer varying levels of savings depending on the type of HVAC system you have and your home’s insulation:
- Forced-air systems: These systems, which include furnaces and central air conditioning, are well-suited for setbacks because they quickly adjust temperatures.
- Hydronic heating systems: These use water to heat the home and may take longer to recover from setbacks, but they can still save energy.
- Zoned heating and cooling: Zoned systems let you adjust temperatures in specific areas of the home, making setbacks particularly effective in unoccupied rooms.
Other Ways of Maximizing Energy Efficiency
While thermostat setbacks are an excellent way to save energy, there are other steps you can take to further reduce your heating and cooling costs.
Improve Home Insulation
Proper insulation helps maintain your home’s temperature, reducing the workload on your HVAC system. Focus on insulating your attic, walls, and floors for the best results. Insulating your home is a long-term investment that pays off by keeping your home comfortable year-round and reducing energy bills.
Seal Air Leaks
Air leaks around windows, doors, and other openings can significantly reduce your home’s energy efficiency. Sealing these leaks can help maintain your desired temperature with less energy use. Weatherstripping, caulking, and draft stoppers are practical and inexpensive steps to eliminate air leaks.
Maintain Your HVAC System
Keep your heating and cooling systems running efficiently by scheduling regular maintenance. This can include changing filters, cleaning vents, and having a professional tune-up annually. Regular maintenance ensures that your HVAC system operates at peak efficiency and can extend the lifespan of your equipment.
Installing Energy-Efficient Windows
Investing in energy-efficient windows can further improve your home’s ability to retain heat in the winter and keep cool air inside during the summer. Double or triple-pane windows with low-emissivity coatings can significantly enhance your home’s energy performance. While replacing windows can be a significant investment, the long-term savings in energy bills make it worthwhile.
Use Your Window Treatments
Window treatments such as curtains, blinds, and shades can provide an extra layer of insulation. During the winter, open your window treatments during sunny days to allow natural heat to enter and close them at night to retain warmth. In the summer, keep window treatments closed during the day to block out heat from the sun.
