SolarCity and Nest have joined forces to promote energy efficiency for homes in California. This month, the first 10,000 new solar customers who sign up for a solar energy system from SolarCity will get a free Nest wi-fi enabled thermostat as well. Working together, SolarCity and Nest will help homeowners save even more electricity.

How does it work? The Nest thermostat is really a tiny computer. Every time you change a setting, it remembers. Within a few days, it knows your schedule, so it can adjust your heating and cooling systems to be more efficient.

For instance, there’s no need to keep the furnace blasting all night long while you are tucked in under your comfy quilt. By the same token, there is no need to keep the air conditioner on high all day while you’re away from home. Nest will automatically bring your home up to temperature before you get up in the morning or cool it down for you just before you get home. Studies show that Nest enabled homes use 56% less electricity for cooling.

Appliances like ceiling fans and other appliances can be networked with Nest. Because it’s connected to the internet wirelessly, your wi-fi enabled car can “call ahead” and tell Nest you’re on your way home. Or a webcam can show you what’s going on inside your home if your internet enabled smoke alarm goes off.

Nest and SolarCity are working with electric companies around the country to help them generate power more efficiently. Generally, the demand curve for electricity drops in the middle of the day, then rises sharply from late afternoon into early evening when people arrive home from work or school. A graph of energy usage throughout the day is often called “the duck curve” because it looks a lot like a duck when plotted out.  It costs utilities money to ramp up electricity production for peak demand times and if some of that extra power gets wasted, the utilities lose money.

But when a home is fully integrated with the web, utility companies will know exactly how much solar power is being supplied to the grid all the time and how much will be needed later. That lets them manage their resources better, which saves them money and lowers your electric bill.

And of course, you can control your Nest thermostat with your smart phone from anywhere in the world. You can even tell it to go into energy conservation mode if you are away on vacation. So you can stop worrying if you forgot to turn the thermostat down or the air conditioning off before you got on the SuperShuttle and headed to the airport this morning. This collaboration between SolarCity and Nest is just the beginning of using wireless connectivity to conserve energy usage.