100A Panel and Heat Pump Installation in BC: Load Calculation and Upgrade Roadmap

Technical reference for BC homeowners and contractors — February 2026

Executive Summary

Most BC homes on a 100A service can support a modern heat pump. The limiting factor is not the panel — it is the equipment choices made at the time of installation.

Three conditions make it work:

Inverter (variable-speed) heat pump — ramps up gradually, draws 8–25A depending on demand, no startup spike
Correctly sized aux heat — a 5 kW strip (21A) instead of the default 10 kW (42A), or no strip at all
Energy Management System (EMS) — watches real-time panel draw and defers non-critical loads automatically

A 100A service gives you 80A of safe, continuous capacity. A well-specified inverter system with EMS draws 28–54A at peak in BC conditions — comfortably inside that limit for most homes.

A panel upgrade is still worth considering if you plan to add a Level 2 EV charger at the same time, or are replacing a large central gas system with a ducted unit and large aux strip. But it is not a prerequisite for heat pump installation on a typical BC home.

The 80A Rule

A 100A panel's real continuous capacity is 80 amps — not 100. The Canadian Electrical Code (CSA C22.1) requires continuous loads to be sized at 80% of rated capacity. A heat pump running during heating season counts as a continuous load.

Everything running in your home at once must fit within that 80A, or the main breaker trips.

Why Load Management Changes the Math

Single-stage heat pumps (older technology) draw full power or nothing — and their startup current spike is 3–5× their running draw. That is what overwhelmed 100A panels in older installations.

Inverter heat pumps modulate between 10–100% of capacity. In Metro Vancouver's mild climate (-5°C to -7°C design temperature), most inverter units run at 30–60% capacity for the bulk of the heating season — drawing well below their nameplate amperage.

Energy Management Systems (EMS) add a second layer. Current sensors at the main panel watch total draw in real time. If a dryer starts while the heat pump is running, the EMS signals the heat pump to slow down slightly. A well-insulated home holds temperature long enough that the occupant notices nothing.

Inverter modulation combined with EMS load management is why the math works on 100A.

The CSA C22.1 80% rule limits a 100A panel to 80A continuous draw. With a 10 kW aux heater, a standard heat pump system hits 82A before accounting for everyday loads — over the limit. Switch to a 5 kW strip and add an EMS, and total draw drops to 54A. The math works when the right equipment is specified.

System Configurations That Work on 100A

Cold-Climate Inverter ASHP (Preferred)

Cold-climate rated units (Mitsubishi Hyper Heat, Daikin Fit, Bosch IDS) maintain heating capacity at -15°C or lower. In Metro Vancouver (design temp -5°C to -7°C), these systems cover 100% of the heating load without activating aux heat for most of the season.

Panel impact: No aux heat draw. Compressor and air handler only — typically 20–28A combined.

EMS with Smaller Aux Strip

If a backup strip is required for code compliance or comfort, specify a 5 kW strip instead of the default 10 kW. Paired with an EMS controller (DCC-9 / DCC-12 or equivalent), the system manages simultaneous loads automatically.

Single-Zone Ductless (Lowest Panel Stress)

A 9,000–18,000 BTU/h ductless mini-split draws 8–15A at peak. If supplementing existing baseboards rather than replacing a central system, a single-zone unit is the most panel-friendly option available.

When a Panel Upgrade Makes Sense

A 200A upgrade costs $3,000–$6,000 on the homeowner side (panel, wiring, permit, inspection) plus $0–$2,500 for the utility service lateral. It makes sense when:

You are adding a Level 2 EV charger at the same time (adds 30–32A continuous — 37–40% of your 80A limit before the heat pump runs at all)
You are replacing a large central gas system and require a 10 kW+ aux strip for design temperature coverage
Your load audit shows less than 20A of available headroom even without a heat pump

Upgrade timeline: BC Hydro service upgrades in Surrey and Vancouver regularly run 8–16 weeks. Start the utility application before finalizing your heat pump quote — not after.

What to Ask Your Contractor

What is the aux/backup heat size in this quote? (Ask for kW and amperage — not just "standard")
Have you reviewed my electrical panel? (A legitimate contractor looks before quoting)
Does this system include an EMS, or how do you plan to manage simultaneous load on a 100A service?
Will this installation comply with CSA C22.1 simultaneous load requirements on my current service?
Is the electrical work permitted under Technical Safety BC? (Ask for the permit number at completion)

If the answer to question 4 is "it should be fine" without showing you numbers, get a second quote.

BC-Specific: Technical Safety BC Jurisdiction

Electrical work in BC — including panel upgrades, EMS installation, and heat pump wiring — is regulated by Technical Safety BC under the Safety Standards Act. Work must be permitted, performed by a licensed electrical contractor, and inspected before re-energization.

If a contractor offers to skip the permit to save time, that is a compliance failure, not a favour.

Verify your electrician's license: Technical Safety BC Licence Search

Next Steps

Metro Vancouver home? Get the region-specific guide: Can I Install a Heat Pump on a 100 Amp Panel? (Surrey & Vancouver)
Check your panel before calling for quotes: Heat Pump Home Assessment Checklist
In a strata? Combine panel planning with approval strategy: Vancouver Condo Heat Pumps: Navigating Strata Approval

Browse Heat Pump Installers in BC

Disclaimer: Load figures in this guide are general reference values. Actual equipment draw must be verified against manufacturer nameplates and confirmed by a licensed electrician performing a formal load calculation per CSA C22.1. Panel upgrade costs vary by location, utility, and existing infrastructure. This guide does not constitute electrical engineering advice. All electrical work in BC requires permits and inspections under Technical Safety BC jurisdiction.