100 A Panel, Heat Pump, and EV: Do You Need a 200 A Upgrade in Ontario?
The Amp Champ team ·
The heat-pump quote looks ready to sign until you reach the electrical line: 200 A service upgrade required. Before you treat that as settled, stop and ask what calculation produced it.
That line shows up on a lot of heat-pump and driveway charger proposals around Collingwood, The Blue Mountains, Wasaga Beach, Stayner, and Thornbury. It is a contractor’s conclusion. It is not, by itself, the Ontario Electrical Safety Code.
The 200 A line on the quote
If you live in southern Georgian Bay and you are adding a cold-climate heat pump or a driveway charger, you already know the equipment is a big decision. The electrical line item is the one that often arrives last and feels settled.
It is not automatically required just because the equipment is new. An ESA technical advisor has said plainly that adding EV supply equipment does not always mean changing the service. It depends on a formal demand calculation, or on documented historical demand for the dwelling.
What you can do safely is pause. Do not open the panel. Do not start adding the loads on a scrap of paper. Ask what written calculation produced that 200 A line, and who is licensed to stand behind it.
What the demand calculation actually decides
The demand-calculation rules in the Ontario Electrical Safety Code set how a home’s service size is worked out. They are not a homeowner worksheet. They are the official math a licensed electrical contractor uses when they add up what the code says could run at once.
The current code is the Ontario Electrical Safety Code now in force, adopted by Ontario’s Electrical Safety Code regulation. It came into force on May 1, 2025.
The calculation does not ask what your house draws on a quiet Tuesday. It asks what the code requires the service to be ready for. Heat pumps and home chargers sit in that math at 100% of their counted load unless a recognized control method applies, according to the ESA bulletin on maximum circuit loading and demand factors.
- Current Ontario Electrical Safety Code in force
- May 1, 2025
- Demand factor for a heat pump and unmanaged EV charging
- 100%
Why heat pumps and chargers trigger upgrade quotes
A heat-pump compressor is not usually the load that makes a 100 A service look tight on paper. The usual driver is auxiliary electric resistance heat in the air handler, sized for the coldest nights.
Trade coverage of Ontario retrofits often points to a backup kit of 10 kW (approx. 41.6 A at 240V) as the strip-heat size that shows up beside a 200 A recommendation (Mechanical Business). That is a typical equipment example, not a measurement of your house.
The ESA bulletin on demand factors is more precise about how the code treats that backup. If the heat pump has no supplemental electric heat, the heat-pump nameplate is taken at 100%. If electric backup is added and both sources can run together, both get counted. If they are interlocked so they cannot run at the same time, the calculation uses the greater of the two heating loads.
A home charger is simpler. Without an energy management system, the bulletin’s worked example counts it at 32 A (7,680 W), at 100%.
That is why a quote can jump to a 200 A service even when the outdoor unit looks modest. The paperwork is often adding strip heat, a charger, and the rest of the house, then comparing the result to a 100 A main.
A full panel is a different problem. If there is no physical space for a new breaker, or the existing equipment is worn out, that is not a load-calculation issue. It is a condition issue. A tripped breaker on a single circuit is also not the same thing as a service that is too small on paper.
“The compressor is rarely what blows past a 100 A calculation. The usual driver is the electric resistance backup sitting in the air handler.”
Three code-compliant paths, not one default
A written demand calculation should consider more than one legal way to add the load. None of these is a verdict for your house.
A full 200 A service upgrade
This is the path the quote already named. It usually means a new main panel and breaker, a new meter base, and a new mast or underground customer-side run, plus an ESA permit and a utility disconnect and reconnect. It creates headroom for later loads. It also puts you on the utility’s schedule, which is not the same as an indoor panel swap.
A certified energy management system
An energy management system is equipment that monitors the service and limits how much of a controlled load can run at once. Since May 1, 2025, Ontario’s amendments go beyond charger-only controls. The amendment on energy management systems allows other energy management systems where increasing the service may not be practicable.
When that equipment is in place, the energy-management rules let the calculation use the managed limit. The system still has to keep the service inside the 80% continuous-loading rule. It cannot repair a damaged or obsolete panel.
We will not name brands here. The question for the quote is whether a certified system was evaluated at all.
Dual-fuel or interlocked backup
If the heat pump uses an existing gas or propane furnace for the coldest weather, the large electric strip kit may not be in the calculation at all. If electric backup is installed but interlocked so it cannot run with the compressor, the ESA demand-factor bulletin points to the greater of the two loads.
That is an HVAC design choice as much as an electrical one. It still has to show up on the written calculation, not as a verbal assurance.
| Full 200 A upgrade | Certified energy management | |
|---|---|---|
| What it changes | Service, meter base, and panel capacity | How much of the new load is allowed to run at once |
| What the code is looking at | A larger service entrance and calculated headroom | A monitored limit that stays inside the continuous-loading rule |
| What it does not fix | Utility-side timing or extra conductor length | A worn, full, or obsolete panel |
| Question to ask | What is customer-side work versus the local utility? | Was a certified system included on the demand-calculation sheet? |
Hydro One and EPCOR change the job, not the code
The code is provincial. The connection is local.
EPCOR Electricity Distribution Ontario serves Collingwood, Stayner, Creemore, and Thornbury. Hydro One covers most of the rural and cottage territory around those towns.
On a Hydro One service, you typically own the meter base, the mast or the customer-side underground run, the main breaker, and the panel. The utility owns the meter and the supply up to the demarcation. Hydro One’s Conditions of Service include a basic overhead connection of 30 metres of secondary conductor for up to 200 A. Longer runs, underground differentials, and distribution changes are extra, and they are site-specific.
Hydro One also publishes timing that belongs in the quote conversation. It is not a promise that your job will hit these dates.
Hydro One timing variables on a service change
| Step | Published timing | What it means for a quote |
|---|---|---|
| First response | 15 calendar days | How long Hydro One says it may take to answer a connection request |
| Offer to connect | 60 calendar days | How long a formal offer can take after they have what they need |
| Temporary disconnect notice | 10 calendar days | Advance notice for the free annual disconnect during business hours |
Hydro One’s upgrade page also says you must apply to the Electrical Safety Authority for a permit before changing the service, and that Hydro One will not connect until ESA approval is in. An ESA permit is required for a service change anywhere in Ontario. The local difference is who schedules the meter and the reconnect.
None of this means a given energy management system will be accepted on the first try. Utility layout, transformer capacity, and the ESA inspection still have to line up. Treat Hydro One and EPCOR as variables in the quote, not as a rubber stamp.
Cottage services raise the same code questions with a different lifestyle. If the panel sits in a seasonal place, the cottage electrical checklist is about how you leave circuits for winter, not about whether the service can accept a new heat pump.
What should you ask before you sign the upgrade?
You do not need to calculate anything. You need answers in writing.
- 1Ask for the demand-calculation sheetA licensed calculation, not a glance at the main breaker, is what the code uses to size a service.
- 2Ask how the heat pump is backed upElectric resistance strips, a dual-fuel furnace, or an interlock change the counted load.
- 3Ask whether a certified energy management system was evaluatedSince May 1, 2025, Ontario recognizes those systems for more than EV chargers.
- 4Ask about the panel's condition and spare spaceA full, damaged, or obsolete panel is a different reason to replace it than a calculated overload.
- 5Ask what is customer-side work versus the utilityMeter base, mast, and extra conductor length sit on your side of the demarcation.
- 6Ask who is pulling the ESA permitA service change needs an ESA notification and inspection before the utility reconnects.
These questions test a quote. They are not a do-it-yourself load calculation, and they do not decide whether your house needs a 200 A service.
Does every heat pump or home charger require a 200 A service in Ontario?
No automatic rule says that. Service size is decided by a licensed demand calculation, or by documented historical demand, not by the equipment brochure.
If the quote skipped an energy management system, is the upgrade invalid?
Not by itself. It does mean the quote has not shown you every code path. Ask for the calculation with and without a certified system, then decide with a licensed electrician.
Can I add up my breakers to check the quote?
No. Adding breaker handles is not a demand calculation, and it is easy to get wrong. Ask for the licensed sheet instead.
Have Amp Champ review the quote
Bring the HVAC or charger proposal, the electrical line item, and anything you already have on the existing panel. We will look at whether a written demand calculation exists, how backup heat was counted, whether a certified energy management path was considered, and how Hydro One or EPCOR would enter the job.
We will not tell you from a blog post that you do or do not need a 200 A service. That answer belongs on a licensed calculation for your house.
If you want that review on paper before you sign, get in touch.
Sources
Ontario’s Electrical Safety Code regulation, Government of Ontario e-Laws, in force May 1, 2025.
Ontario Electrical Safety Code updates, Electrical Safety Authority.
Ontario amendments on energy management systems, Electrical Safety Authority.
ESA podcast transcript on EV supply equipment, Electrical Safety Authority.
EPCOR Electricity Distribution Ontario, Conditions of Service.
How heat pumps affect the need for service upgrades, Mechanical Business.