Upgrading from 100-amp to 200-amp service is one of the most common projects we quote, but it's also one where homeowners often assume they need it when they don't — or skip it when they should. The decision comes down to one thing: how much load you're adding versus how much headroom your panel has.
When the upgrade is worth it
Two hundred-amp service makes sense when you're adding significant electrical load to a panel that's already near capacity. The classic triggers:
- **An EV charger**, especially a Level 2 unit, which adds a large continuous load. - **Electrification** — switching from gas to electric heat, adding a heat pump, an electric water heater, or an induction range. - **A hot tub, pool, or central air conditioner.** - **A basement apartment or second unit**, which needs its own circuits and capacity. - **A major renovation** — a new kitchen, an addition, or a finished basement that adds many circuits.
If your panel is already full (no spare breaker slots) or your loads add up beyond what 100 amps can supply, the upgrade isn't optional — it's what makes the project possible.
When 100 amps is genuinely enough
Plenty of GTA homes run perfectly well on 100-amp service. A home with gas furnace, gas water heater, gas range, and ordinary appliances rarely comes close to its limit. If you're not adding major loads, upgrading "just in case" usually isn't money well spent — the capacity you already have is sufficient. A panel that's simply out of breaker slots can sometimes be addressed with a sub-panel rather than a full service upgrade, depending on the actual amperage in use.
How the decision is actually made: the load calculation
This is the part that replaces guesswork. A licensed electrician performs a **load calculation** following the Ontario Electrical Safety Code — totalling your home's square footage, heating, appliances, and any new loads — to determine whether your existing service can carry the addition or needs to grow. It's the same calculation the ESA inspector expects to see, and it's why a good electrician won't quote a blanket "you need 200 amps" over the phone without understanding your loads. For sizing fundamentals, see what size electrical panel does my house need.
What it costs and involves
A 100-to-200-amp upgrade in the GTA typically runs **$3,200–$4,500**, including the ESA permit and inspection. The work replaces the panel, and usually the meter base, main service conductors, and grounding — bringing the whole service entrance up to current code. It's often a one-day job, though coordinating with the utility for the actual connection can add scheduling time. The ESA notification and inspection are included in our quote, never an add-on.
If you're planning an EV charger, a heat pump, a hot tub, or a basement unit and aren't sure whether your service can handle it, we'll run the load calculation and give you a straight answer — upgrade or not. Call 416-837-4038 or request a free estimate; we do panel and service upgrades across the GTA.