That black box in your living room? The one that plays basketball, or the news, and seems to be running constantly—even, if you’re like many families, when there’s no one in the room? It’s hardly the biggest electricity draw within your home.

Neither—and this is more likely to surprise you—is the clothes washer or dryer.

By a wide margin, the biggest energy draw in your home is an electric water heater. For a family of two, the typical water heater costs more than $200 to run for a year. The next-biggest draw, an electric clothes dryer, averages $96 per year.

We know we talk a lot about saving electricity, and we also know that many of our members wonder exactly where their electricity dollars go each month. Without a home energy assessment, we can’t tell you exactly, but we do have some general information about the relative expense and typical averages of the stuff that most homes use.

Eyeballing the following chart gives you a pretty clear idea why we offer water heater rebates and really hammer home the idea that you should consider upgrading. (Perhaps even to a geothermal system.)

The chart gives you some idea where you can get the most savings month after month. But if you’re especially curious, you might look into an electricity usage monitor. This $25-$50 device attaches to any 120-volt outlet so that you can see exactly how many watts whatever you’re plugging in is using. (Or contact your Energy Advisor; he or she may well have one to loan out.)

Or better yet, schedule a home energy assessment. Doing so gives you exact information about electric usage, including a detailed rundown of where you can save throughout your home.