Embracing and investing in energy efficiency at home requires knowledge. In the past, this knowledge was hard to get. You may be able to see that your thermostat was set to 72 degrees, but your thermostat couldn’t tell you how that temperature setting affected your energy usage, let alone how that would affect your monthly bill.

But that’s changing. Energy innovators aren’t only designing new ways to make products more efficient, but are creating ways to bridge the information gap and empower homeowners to manage their energy use. Innovators are taking their ideas and products to where people are, which has led to the release of a slew of exciting and powerful smartphone apps.

Below are just a few of the ways you can improve our energy outlook, reduce our dependence on fossil fuels, and save yourself money, just with the power of your phone.

Heating and Cooling Efficiency Apps

Climate control—heating your home in winter and cooling it in summer—accounts for 48% of home energy use, so it’s an obvious target to reap efficiencies. When thinking about how to reduce energy consumed for climate control, it’s important to consider two scenarios: what happens when you are home and what happens when you’re not? Energy-savings apps can help with both.

With winter coming, thermostats around the country are inching up. While the U.S. Department of Energy typically recommends thermostat settings of 68 degrees in winter, the average living room is 2 degrees warmer. It also pays to think about what’s happening when you’re not home. Most folks aren’t home for a significant portion of each day, and when you’re at the office or out for the night, no one’s around to enjoy your comfortably heated home. Turning back your thermostat 10-15 degrees for the eight hours while you’re at work can save you 5 – 15% on your energy bill—nearly 1% per degree. When you know how much energy each extra degree of heat costs, it’s easier to justify turning down the thermostat and putting on a sweater.

Nest is perhaps the most recognized “smart thermostat.” The Google-owned company’s signature product connects with the utility company and provides you real-time data on your energy usage. This information is accessed on the Nest mobile app, where you can also see energy usage history. The app uses this information to suggest ways you can adjust your temperature from within the app itself to save energy and money. Nest may get most of the press but users have also raved about Ecobee, Honeywell, and Sensi products, all of which share information and allow you to control your home temperature via mobile app.

For those who don’t have a Nest thermometer or renters who can’t change out their energy management systems, there are other apps that can help you understand the impact of your climate control choices on your energy use. Energy calculators (like this app for Android) don’t require hardware, but based on estimates can help you understand how changes can lead to savings.

Gadgets can be energy hogs

On the heels of climate control are all the things you plug in, from your hair dryer to your refrigerator. While it may seem obvious that your fridge would be a large energy consumer—it is, after all, a large appliance—in some households, keeping the family’s iPhones charged uses more energy than keeping food fresh.

Other big energy hogs? Cable and other TV set boxes and gaming consoles. And while refrigerators have become more efficient over the last few decades, we don’t hear much about improving energy savings in our Xboxes.

Knowing which of your appliances are responsible for higher energy bills can help direct your choices about where to save. Are you one of those people who leaves the TV on as background noise? Now that you know your cable box is an energy hog, you could think about switching to music or minimizing TV time to when you’re focused on the program. You could change your TV’s settings to dim the screen or think about replacing your set with a more efficient model.

Appliances

Many of the same apps that help control your heating and cooling can give you information about your appliance usage as well, while devices like MeterPlug focus specifically on your appliances. Connecting directly to one appliance or a power strip to monitor several appliances, MeterPlug collects usage data and sends it to an app on your smartphone. There, you can analyze and find the energy guzzling culprits and figure out what to use less or replace. Many apps operate like energy calculators that focus on a single appliance. You name the brand and model (input the energy usage estimates provided by the manufacturer), the hours of usage each day, and your utility’s rates, and the app will spit out estimated costs.

Improving energy efficiency isn’t just about assessing what you have, but also evaluating what you’re buying. The Department of Energy’s Code Green App is designed for real estate professionals, but can enable any tenant or prospective homeowner to view and analyze Energy Star® scores of thousands of buildings right from their smartphones. New Energy Star® disclosure requirements in cities such as New York, Seattle, San Francisco, and Austin have increased the importance of higher scores. The CodeGreen Energy App enables easy search and comparison for thousands of buildings throughout the country.

Code Green also allows you to look up the EnergyStar ratings of appliances on the go. That way, if a dishwasher or microwave is on sale, you can get the information you need to decide whether it’s worth it on the spot instead of missing out on the opportunity or being forced into making an uninformed purchase.

Likewise, Light Bulb Finder helps ease the transition from incandescent to energy efficient light bulbs by both helping you find environmentally friendly equivalents to what you’re used to and telling you what stores sell them.

The old standbys of turning off the lights when you leave a room and unplugging appliances you’re not using are still great ways to save energy. But mobile technology opens up new opportunities to better understand the makeup of our energy bills and how we can make changes that will have the biggest impact on greening our homes. The residential sector accounts for 25% of energy use in the U.S. Arming people with more information about their home energy use habits can, collectively, make a real difference that helps put us on a more sustainable path.