Using a smart meter to track home energy use

What does a smart meter measure?

A conventional meter adds up total energy and someone reads it once in a while. A smart meter stores readings at regular intervals, often every hour or every fifteen minutes, and transmits them automatically. That is what allows time-of-use billing, remote reads and faster outage detection.

Many Canadian provinces have rolled out smart meters for electricity in recent years, and some also for gas and water. Whether yours has one, and what data you can see, depends on the utility. The way to find out is to ask the electric or gas utility or look for an online customer account.

How do you get at your own usage data?

Start with the utility's customer portal or app. Common views include a daily and hourly chart, a monthly total and a comparison with the same period last year. Some utilities also let you download the data as a spreadsheet file, which is easier to analyze.

If you cannot see interval data, ask the utility whether it can be released to you and in what form. Privacy rules govern who else can access the readings, so also ask how the utility shares them with third parties. A separate device clamped on your electrical panel can give more detail, covered in home energy monitoring.

What can the data tell you?

Three patterns are worth looking for.

• The overnight baseline. The lowest usage in the small hours is the standby load from fridges, routers, chargers and idle electronics. As an assumed example, 0.4 kW running all day is 0.4 x 24 x 30, about 290 kWh a month. If the baseline looks high, something is on that need not be.
• Daily peaks. Morning and evening bumps show cooking, laundry and electric water heating. Under time-of-use rates, moving a few of these to cheaper hours can lower the bill. Rate structures differ by province, so check yours.
• Heating and cooling response. Compare days of similar outdoor temperature. On a cold day, a heat pump or electric heat will show up as a large, sustained block of use. The guide to lowering your heating bill in winter pairs well with this check.

How can you act on what you see?

Turn each pattern into a test. If the overnight baseline is high, switch off groups of devices at the breaker and see whether the line drops. If winter use climbs sharply with the weather, the house may be losing heat through the envelope, and a home energy audit will show where. A smart thermostat can shave the peaks, and the savings from either step depend on the house and the rates.

Homes with solar need a different view, because the meter also records exports. The things to track are listed in solar system monitoring. Utilities may also use the same data to run programs that reward flexibility, as described in virtual power plants.

What are the limits of smart meter data?

A smart meter sees the whole house, not the individual appliance. It cannot tell you directly whether the spike at 6 p.m. is the oven or the dryer. It also records only the energy the meter handles, so a gas furnace's consumption appears on a gas meter, if at all, and wood or oil heating does not appear. Data may arrive with a delay, and billing estimates can differ from interval totals.

For context from our own subject, the homes at Drake Landing Solar Community in Okotoks, Alberta, had their space heating measured at the Energy Centre rather than at each house, which is why the community's monitoring could report a solar share for heating. The approach is described on the performance results page.

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