Solar 101
How We Size A Battery For Your Solar System
Battery sizing isn't one-size-fits-all. Here's what actually determines how much storage you need.
Battery sizing isn't one-size-fits-all. Here's what actually determines how much storage you need.
Once a homeowner decides a battery makes sense, the next question is almost always "how big a battery do I need?" The honest answer depends on what you're trying to accomplish, not a flat recommendation that works for every GTA home.
The biggest sizing decision is whole-home backup versus essential-circuit backup. A whole-home battery setup covers your entire electrical panel during an outage, including appliances like AC and electric dryers, and needs significantly more capacity. An essential-circuits setup covers the fridge, furnace, well pump if you have one, and a handful of outlets and lights, and can run on a smaller, less expensive battery for longer.
We look at your typical daily electricity consumption, especially in the evening hours when solar isn't producing, since that's when stored energy actually gets used, either to cover usage during an outage or to avoid drawing from the grid during expensive on-peak pricing. A household running mostly in daylight hours needs less battery capacity than one with heavy evening and overnight usage.
Homes in areas with more frequent or longer grid outages generally benefit from larger battery capacity or multiple battery units, since the battery needs to carry the home for longer stretches without recharging from solar or the grid. We factor in your specific location and utility when making a sizing recommendation.
Battery storage paired with new solar can qualify for rebates under the Home Renovation Savings Program, which is part of why we always run the load displacement math alongside net metering before recommending either path. See our battery storage service page for how backup power and bill savings work together, or talk to our design team about sizing a system for your specific home.
