How do electric meters work?

Unless you live in an off-grid home, you have an electric meter. Your electric meter tells your utility how much electricity you've used over a given time period so that they know how much to charge you on your monthly bill. There are a few different types of electric meters, all of which function in slightly different ways, including net meters that work for solar homes. In this article, we'll break down the different types of meters, how they work, and why you should care about what kind of electric meter you have.

Your electric meter measures your connection to the electrical grid, keeping track of how much electricity you pull from the grid. Historically, electric meters were analog–just numbers on gears and a dial that spun as you consumed more kilowatt-hours (kWh) of electricity. They required a utility worker to come to physically walk to the side of your home and read take a meter reading–literally, writing down the number on your meter. The difference between one reading and the previous one is how they determined your bill amount.

As with other technologies, electric meters have become more advanced over time, making the meter reading process more automated. First, electric meters were adjusted to either passively or actively emit readable radio waves: instead of having to walk to the side of your house, utility workers could drive specially outfitted trucks through your neighborhood and collect readings for each meter much quicker.

Next, utilities began to install "advanced metering infrastructure," alternatively referred to as AMI or smart meters. These smart meters have two key benefits: first, they are able to track electricity usage on a much more granular level–i.e., your power and energy consumption over fifteen or even five-minute intervals–and, second, they are able to automatically communicate with your utility, meaning there's no need for anyone to ever visit your property or drive through your neighborhood to collect usage information for billing.

Finally, if you install solar on your home, your utility may swap out your old electric meter for a net energy meter to track both how much electricity you pull from the grid as well as how much solar you export to the grid. You may also be outfitted with a production meter to track exactly how much solar your panels generate for any local incentive purposes (like for the SMART program in Massachusetts).

The type of electric meter you have influences the type of rate that your utility can charge you for electricity. For instance, if you have an older analog meter, your utility only has visibility into how much electricity you've used between readings, without any insight into when you use electricity or the most amount that you're using at one point in time. As a result, your utility can only charge you one rate for all of the electricity you use.

However, if you have a smart meter, then your utility company has much greater insight into when you use electricity and how much you're using at a given point in time. With that information on hand, your utility has enough of a window into your consumption habits to be able to place you on a time-of-use rate (where the rate you pay for electricity varies based on the time when you use it) or a demand charge rate (which charges you more based on the maximum amount of electricity you pull from the grid at any one time).

Both of these types of rates have pros and cons for home and business owners – depending upon your usage habits and particular circumstances, you may pay more or less for electricity each month. But in either case, if your utility has insight into hourly–or even sub-hourly–usage at your home, they're likely to provide you with that same insight in your utility account, which is a great way to better understand your usage and how it impacts your bill.

One additional thing to keep in mind is that the type of electric meter you have impacts the ease of your solar installation process: if you already have a smart meter installed, you can provide installers with much greater depth of detail into your usage to allow them to design the best possible system for your needs. And depending on your utility, you may not even need a new net meter installed if you already have a smart meter.

Regardless of what kind of electricity meter you have at your property, the best way to take control of your electricity usage is with solar. To see how much you can save by going solar, check out EnergySage's online Solar Calculator. If you're interested in receiving custom solar quotes from local installers, register for a free account on EnergySage today.