Explaining Nest thermostat savings

Google Nest thermostat energy savings projections are based on real world data from actual household use of our thermostats, studies and experiments performed by Nest, as well as multiple independent studies conducted by third parties and energy companies. On average, customers who install a Nest thermostat save money on their heating and cooling bills. Individual savings are not guaranteed.

Thermostats matter a lot for overall energy use

In the average home, heating and cooling account for about half of energy use as determined by the US Department of Energy. This means that a thermostat that efficiently controls your system can have a significant impact on your home energy use and can reduce your overall energy bill.

In February 2017, the Nest Learning Thermostat became the first Programmable thermostat to receive an ENERGY STAR® certification. The newer Nest Thermostat E is now also certified. ENERGY STAR is a U.S. Environmental Protection Agency (EPA) voluntary program that helps businesses and individuals save money and protect our climate through superior energy efficiency.

Ways Nest thermostats can help you save

Here are a few of the ways that Nest thermostats can help reduce the amount of energy used by your heating and cooling system:

Setting efficient temperatures when you're away or just want to save more

When you first install your thermostat, you'll select
your Eco Temperatures. Eco Temperatures are used by
your thermostat to help save energy. You can change
the Eco Temperatures you've chosen at any time on
your thermostat or with the app. To help save more
energy, you should keep energy efficiency in mind
when setting your Eco Temperatures. The exact
temperatures you might pick will vary depending on
your preferences. You should keep in mind how well
insulated your home is, what the weather is like where
you live, if you have any pets, or other things that
might influence what temperature you're comfortable
with choosing. See this article for some quick tips:

Quick tips for choosing energy efficient Eco Temperatures >

nest thermostat eco

Your thermostat can automatically switch to your Eco Temperatures when you leave using Home/Away Assist. If you've chosen energy efficient temperatures, this means that you'll use less energy because your thermostat won't turn on your heating and cooling systems as often while you're gone.

Some people also like to use Eco Temperatures while they're home to help maximize energy savings. Instead of turning the system off or adjusting the temperature by turning the ring, you can quickly switch Eco Temperatures on. Your thermostat will stay set at your energy saving temperatures until you manually switch it out of Eco.

Turning down automatically when you're away

Home/Away Assist can use information from your
Nest product activity sensors and your phone location
to know when you're home and when you're away. If
you're away, your thermostat can switch to your Eco
Temperatures so that you're not wasting energy
heating or cooling an empty home.

When you come back, your thermostat will
automatically switch back to heating or cooling
your home, so you won't need to worry about switching it
back.
 

Note: You'll need to enable phone location in the app
if you'd like your home to automatically switch between
Home and Away using your phone's location. You can learn
more about how Home/Away Assist uses your phone location here:

How Home/Away Assist uses your phone’s location >

Nest thermostat USE ECO

Helping look after your HVAC system's health

Maintenance can have an impact on your heating and cooling system's efficiency. Changing out dirty or clogged air filters is one way to help keep your system running efficiently.

Everyone's home is different, but you should change your air filter regularly. You may need to change it more frequently depending on how often you run your heating and cooling system, the type of filter, and your indoor air quality (e.g. shedding pets, outdoor air pollution levels). Having dirty or clogged filters can mean that your system has to work harder to move air through your home. Your Nest thermostat can help you remember when it's time to change the filter with a Filter Reminder.

Your thermostat can track the last time you changed your filter and show you reminders on your thermostat when it's time to change the filter.

                  Nest air filter reminder Nest reminder filter settings

 

Programming an efficient schedule automatically

A properly programmed thermostat will help you save energy and reduce your bill (http://energystar.gov). Some tips to help you save energy include keeping the thermostat at energy saving temperatures for long periods of time, for example, when you're away from home or sleeping.

Programming a thermostat correctly can sometimes be difficult or time consuming, so some people simply don't do it.

Nest thermostats offer three ways to reduce the hassle of programming your thermostat and make it easy to help save more energy: Auto-Schedule (both thermostats), manual schedule (both thermostats), and Basic Schedule (Nest Thermostat E only). These options can help you save energy by not using your heating an cooling as often or as long as you would without a schedule.

Auto-Schedule

All Nest thermostats can let you use Auto-Schedule to automatically create a schedule that's customized for you and your home. After your thermostat is first installed (or reset), you'll use it just like a normal thermostat. You can turn the ring up when you want it a little warmer and down when you want it a little cooler. After about a week, the thermostat learns about your patterns and what temperatures you like, and programs itself accordingly.

How Nest thermostats learn >

Manual schedule

Like programmable thermostats, your Nest thermostat allows you to set your own custom schedule. Unlike normal programmable thermostats, you can use the Nest app to make it easy to view or customize your schedule with just a few taps.

You can create a schedule that fits you and your home, and the app will show you temperatures that can help save energy. You'll also be able to manually change your schedule even if you're already using another schedule type like Auto-Schedule or Basic Schedule.

Learn more about changing your temperature schedule >

Basic Schedule

If you have a Nest Thermostat E, you'll also have the option to use a Basic Schedule. The Basic Schedule is an average temperature schedule based on information for the area where you live. When you select Basic Schedule, it will give you a pre-programmed schedule that you can use as is, or you can customize it to fit your home.

Using a Basic Schedule is a great way to save energy and skip the hassle of programming an entire schedule from scratch.

Making small adjustments automatically to save energy

If you live in certain areas, you may be able to enroll in a voluntary program called Seasonal Savings through your energy provider. Seasonal Savings allows your thermostat to make small, automatic adjustments to your temperature schedule over the period of a few weeks, leaving you with a more energy efficient schedule over time.

Seasonal Savings has helped Nest thermostat uses save even more -- adding an average of about 3-8% on top of their existing heating and cooling savings (source).

Because Seasonal Savings makes changes that are small over a few weeks, you have time to get used to your new schedule. Saving energy is important but you'll always be in control. If your new temperature schedule is too hot or too cold, you can always change the temperature on your thermostat, change your temperature schedule, or unenroll from Seasonal Savings.

If your energy provider offers Seasonal Savings in your area, you may receive an invitation to turn it on.

The Nest Leaf can Help you to choose efficient temperatures

The Nest Leaf encourages you to choose more energy-efficient temperatures. The Nest Leaf Nest thermostat leaf icon  icon appears on the thermostat display or in the app when you choose an energy-saving temperature.

The temperatures that earn the Leaf will depend on your temperature preferences, your home, and your schedule. The Leaf will challenge you to choose temperatures that are a little lower or higher than you're used to.

The range of temepratures that earn a Leaf will also change over time as your Nest thermostat continues to learn and as you save energy. 

Savings results with Nest thermostats

Multiple studies, including studies run by energy companies independently from Nest, have shown that on average customers save 10-12% on heating and 15% on cooling after a Nest thermostat is installed. Based on typical energy costs this means a savings of $131-145 a year.

Where those numbers come from

We looked at the energy bills of real people in 41 states before and after they installed Nest thermostats, as well as looked at data from two independent studies from real homes with real families using Nest thermostats.

How much energy can you save

Every home is different. You can expect different savings depending on what temperatures you kept your old thermostat set at, where your home is located, and other factors like insulation and heating and cooling system efficiency. To help provide an estimate for your home, we developed the savings calculator.

Savings Calculator >

The savings calculator helps you find out how much you could save by installing a Nest thermostat. It will even tell you if there are utility programs in your area that offer rebates or other incentives.

The savings calculator estimates energy savings of the Nest thermostat by using some basic information that you provide. It uses your ZIP or postal code, home size, heating type, and whether or not you have air conditioning.

Learn more about how the savings calculator works >

How different manufacturers calculate savings

Energy savings can be an important part of deciding which thermostat to purchase. But, not all estimates of potential energy savings from a thermostat are created equal.

Different ways manufacturers calculate energy savings

There are a few different ways that energy savings estimates are made.

Manufacturers can:

  • Use a model with an imaginary customer and some assumptions to estimate savings.
  • Examine real world data before and after installation in real customer's homes.
  • Design a controlled experiment to measure energy savings of the thermostat.
  • Use a mix of these and other methods.

Take a look at these different methods in more detail:

Using an imaginary customer to estimate savings

If you're going to try to understand how much your thermostat can save, you need something to compare it to. In this method, a company will use some assumptions about the average consumer to create a baseline estimate of energy use (without their product). And then will compare it to projected usage with their product.

For example, you could assume that before installing a smart thermostat, a customer keeps their thermostat set at 72 degrees 24/7 all year long. This customer would see significant savings after installing a smart thermostat that has a schedule programmed and can turn down the heating and cooling system when they leave.

Using this method, we've calculated that installing a Nest thermostat could save the average customer a whopping 25% on their heating and cooling energy use.

However, this savings estimate might be overly optimistic because the average person doesn't leave their thermostat set at one temperature 24/7 all year long. if you already have a schedule programmed in your thermostat, or if you change the temperature on your own, you probably don't have as much room to save as this model-based approach would suggest.

Since this estimate does not accurately reflect what real world customers are likely to see, Nest does not generally use this method for determining energy savings numbers.

Examining real world customers and data to calculate savings

A good way to use real world data to calculate energy savings is to look at customer's energy bills before and after installing a smart thermostat. Energy bills show your total energy usage, so you can check for decreased energy usage after a smart thermostat is installed.

Other factors, like weather, can also cause energy use to change significantly, so it's important to include a control group. A control group is a set of customers, who have similar homes and live in the same area, that continue to use their old thermostat instead of installing a new smart thermostat. Control groups can help adjust for factors like changes in weather to help determine more clearly the amount of energy savings generated by the smart thermostat.

For example, maybe this winter was a lot colder than the last. If you installed a smart thermostat between the two winters, you could actually see higher energy use this year because your system has to run more to keep your home at a desired temperature during this colder winter. But, once researchers control for the difference in the weather, they might find that the smart thermostat did help you use less energy than you would have without it.

It's also important to look at different regions. Some parts of the world are more temperate, and you wouldn't need to use your heating and cooling very often. This means that even though a smart thermostat could save you energy, it might not reduce your usage as much as it would for someone who lives in an area where heating and cooling usage is high.

By including control groups, accounting for weather and regional differences in heating and cooling, and comparing energy bills before and after a smart thermostat is installed, you can get a clearer picture of total energy savings.

nest.com/real-savings >

Which methods Nest uses to calculate savings

Nest prefers to use real world data and scientific analysis when calculating energy savings to help provide savings estimates that are as close as possible to what you might see in your home.

Not all savings claims are based on scientific analysis or use real world data, and you should keep this in mind when comparing numbers from different manufacturers. Methods that rely solely on using an imaginary customer to estimate savings can result in an energy savings number that is much higher than you're likely to see in your home.

We base our energy savings calculations on controlled experiments as well as real world data gathered through multiple studies that each compared customer utility bills before and after installing a Nest thermostat. This includes several studies that were conducted by utility companies and other third parties independently from Nest. We also track the performance of our thermostats using a variety of approaches including the EPA's Energy Star performance metric developed for smart thermostats.

These studies all used established methods for measuring energy savings. They included methods for statistically adjusting for weather differences from year to year and control groups to reflect trends in energy use over time.

By using data from real customers and independent studies, we're able to see that Nest thermostats save energy in real world situations, not just estimates or simulations based on imaginary people. On average, customers who install a Nest thermostat save money on their energy bill, and your Nest thermostat can pay for itself in under two years.

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