The short answer is that shutting down your air conditioner or heater during the day is the best way to save energy. But there’s more to the problem than energy use – alternative forms of cooling and heating as well as the desire for comfort will affect how often you leave your HVAC running while you’re gone.
Why Should I Turn My Air Conditioner Off?
When you leave your air conditioner off during the day, the entire system doesn’t have to do any work.
Save Energy On Cooling
When your air conditioner runs throughout the day, it’s using energy all day. If you work an 8-hour job, that means that it’s turning off and on (or staying on if you don’t set it to Auto) and constantly using energy.
Many people argue that it requires more energy to cool your home after it warms up throughout the day. However, your thermostat does not control the amount of work that your air conditioner does, it only controls when it will turn on. Even if your air conditioner has to work for 30 minutes to cool your home after a hot day, it still requires less energy than leaving it running or on Auto for a full day.
Save Energy On Your Thermostat
The thermostat detects the current air temperature and records the temperature at which you want the air conditioner to begin cooling your house. When your HVAC is turned on, it is constantly reading the temperature and waiting on standby to cool your house the moment it reaches the temperature you have set.
The electronics inside your HVAC will be running while it is set to Auto or On. Even at a high temperature, your thermostat will force your HVAC to run on standby all day. The electricity use while you are away is largely a waste of electricity.
What Other Factors Should I Consider?
Comfort Level When You Return Home
You may want to walk into a comfortable, air conditioned home at the end of a hard workday. Since cooling off a hot home will take time, commuters often leave the AC running during the day so they don’t have to wait for cool air in the evening.
The energy cost may be worth the trade off for you, but remember that your AC could potentially be running for an additional 7.5 hours should you leave it running.
Alternative Cooling Methods
Your HVAC isn’t your only lifeline when it comes to cooling. Desktop and ceiling fans are effective cooling devices if you’re looking to save on energy costs. You can reduce the discomfort of recooling your home when you return from work with the help of fans.
Fans recirculate the air in your rooms at their current temperature – they don’t actually cool the air. However, circulating air helps cool the skin and evaporate sweat, which lowers your body temperature.
As your HVAC begins to bring cool air into your home, your fans will circulate that cool air and evenly drop the temperature throughout your entire room. This will help your thermostat control your air conditioner with maximum efficiency.
Consider the total energy use of your air conditioner on a normal day and determine if the added comfort is worth the cost of the extra energy required to run the unit. In most cases, you’ll save money and extend the life of your AC by switching it off while you’re gone during the day.