Most heat pump installations in Halton and Hamilton do not need a panel upgrade, and the thing that decides it is not the size of the heat pump. It is whether you are keeping a gas furnace as backup or going all-electric with resistance heat strips. A cold-climate heat pump on a hybrid system typically adds one 240 V circuit in the 20 to 40 amp range, which a healthy 100 amp service usually absorbs. Bolt 10 kW of electric backup onto the same job and the calculated load can exceed what that service is allowed to carry.
Panel Space and Service Capacity Are Two Different Problems
People use panel upgrade to mean both, and conflating them leads to the wrong quote. Panel space is physical: how many breaker slots are left. If that is all you are short of, tandem breakers where the panel permits them, or a small subpanel, solve it inexpensively.
Service capacity is electrical: how many amps the service conductors, the meter base and the main breaker can carry. A subpanel adds exactly zero capacity — it just gives you more places to connect to the same supply. Look at the number stamped on the main breaker rather than the label on the panel door, because a 200 amp-rated enclosure fed by a 100 amp main is still a 100 amp service.
What the Electrician Actually Calculates
A licensed electrical contractor runs a calculated load for the dwelling under the Ontario Electrical Safety Code. It takes the floor area, then adds the fixed loads — electric range, electric water heater, EV charger, and space heating or air conditioning, counting the larger of the two rather than both, since you do not heat and cool simultaneously.
- The heat pump's contribution comes off its nameplate, not off its tonnage. Minimum circuit ampacity sets the wire size and maximum overcurrent protection sets the breaker.
- Electric backup heat is the swing factor, and the arithmetic is simple: at 240 volts, 5 kW is about 21 amps, 10 kW is about 42 amps, and 15 kW is about 63 amps.
- That is why a hybrid system with a gas furnace behind the heat pump is so much easier on an older service — there are no strips at all.
- An EV charger already installed changes the answer completely, and so does an electric range plus an electric water heater in the same house.
- Rural properties on the Escarpment carry loads suburban ones do not: a well pump, a septic pump, sometimes a shop subpanel. They all count.
Which Local Houses Usually Need the Upgrade
- 1950s and 1960s bungalows in Aldershot, on the Hamilton Mountain and in older Stoney Creek: frequently 60 or 100 amps, sometimes still on an original fuse panel. A 60 amp service needs upgrading for almost any electrification project.
- 1970s to 1990s subdivisions — Millcroft, Tyandaga, Glen Abbey, River Oaks, the older parts of Binbrook: usually 100 or 125 amps. Fine for a hybrid heat pump, tight once you add electric backup or a car charger.
- 2000s and newer builds in Alton Village, Joshua Creek and Waterdown: 200 amps is the norm and the question rarely comes up.
- Condominium suites: there is no service upgrade to buy. The suite panel and the building's own capacity set the limit, which is why suite heat pumps are usually small and ducted through existing fan-coil openings.
- Century homes with an early breaker panel and knob-and-tube remnants: the heat pump may be the smallest part of that conversation.
Three Ways to Avoid a Full Service Upgrade
Before you accept a service upgrade as unavoidable, ask the contractor to price these three alternatives. In our experience at least one applies to most houses.
- Keep gas as the backup. A hybrid system runs the heat pump for most of the season and lets the furnace take the deep-cold nights, which removes electric strips from the calculation entirely — see our hybrid heat pump page for how the balance point is chosen and what it costs to get it wrong.
- Use a certified load-management device. These shed a large load — the backup heat, or the water heater — when total demand would otherwise exceed the service. They are a recognised approach when the device is certified and installed to its listing; have your electrical contractor confirm acceptability with the Electrical Safety Authority for your specific panel.
- Right-size the backup heat. Plenty of quotes include 10 kW of strip heat as a default when 5 kW covers the actual shortfall on a properly sized cold-climate unit. That single change can halve the added load — start from what size heat pump do I need.
Free quotes, written pricing.
A fourth option exists if you are already renovating: retire another big electric load. Moving an electric water heater to gas, or to a heat-pump water heater, frees up meaningful capacity.
Who Signs Off, and Who Else Has to Say Yes
Electrical work of this kind is done by a licensed electrical contractor, who files a notification with the Electrical Safety Authority so the work can be inspected. That inspection is separate from any municipal building permit covering the mechanical side of the job.
A service upgrade also involves your local distribution utility, because the service conductors, the meter and, on an overhead service, the drop from the pole belong to them. In this area that means Burlington Hydro, Oakville Hydro or Alectra Utilities in Hamilton. Their scheduling, not the electrician's, is usually what sets the date — plan the heat pump around it rather than the other way round. On older streets with overhead service, the mast and weatherhead often need replacing at the same time.
We do not publish a price for panel or service work because it is the electrician's scope and the utility's involvement changes it house by house. What we will do is tell you before you sign whether your service is likely to be a problem, so the electrical quote arrives in the same package as ours.
Where This Lands in a Heat Pump Budget
For context on the rest of the project: a 3-ton cold-climate heat pump installs for $9,500–$15,000, and ducted whole-home systems run roughly $6,000–$16,000 installed before rebates depending on capacity, brand tier and the electrical work needed. Current Ontario programs return $500–$7,500 depending on the system, and we file the paperwork — the current amounts and eligibility rules are on our rebates hub.
Ask for electrical to be quoted as its own line rather than folded into a single number, so you can compare bids properly. Our guide on how to compare HVAC quotes explains what else to line up side by side.
Verdict: Do You Need One?
- Probably not, if you have 100 amps or more, you are keeping a gas furnace as backup, and you do not have an EV charger plus an electric range plus an electric water heater already competing for the service.
- Probably yes, if you are on a 60 amp service, you are going all-electric with 10 kW or more of strip heat, or the calculated load already sits close to the main breaker rating.
- Get it calculated, always. A calculated load takes an electrician under an hour and is the only thing that turns this from opinion into an answer.
We size heat pumps for Burlington, Oakville and Hamilton homes with the electrical reality in mind, and we would rather flag a service problem at the quote stage than discover it on install day. See our heat pump installation service or ask us to check your panel while we are measuring for the system.
Frequently asked questions
Can I run a heat pump on a 100 amp service?
Often yes, particularly in a hybrid setup where a gas furnace handles backup heat and the heat pump adds a single moderate circuit. What pushes a 100 amp service over is usually the combination of electric backup heat plus other large electric loads. Only a calculated load done for your house answers it properly.
Does a subpanel count as a panel upgrade?
No. A subpanel gives you more breaker positions fed from the same service, so it solves a space problem and does nothing for a capacity problem. If the electrician says you are short on amps rather than short on slots, a subpanel will not help.
How much of the heat pump budget should I set aside for electrical?
We do not publish a figure because it swings from a single new circuit to a full service upgrade with utility involvement. Ask for it as a separate written line on the quote. If a contractor will not break it out, that is a reason to get another quote rather than to assume it is small.
Will I need a permit for the electrical work?
The licensed electrical contractor files a notification with the Electrical Safety Authority and the work gets inspected — that is standard for any new circuit or service change. Municipal building permits are a separate matter and depend on the mechanical scope, so confirm both with your contractor before work starts.