Standard and code basis

Residential service load calculations in Canada are governed by CEC Part II, Rules 8-200 through 8-210 (CSA C22.1-21). The key rules implemented are:

CEC RuleWhat it governs
Rule 8-202Basic load — floor area-based general lighting and outlet circuits
Rule 8-204Small appliance load — kitchen and dining area circuits
Rule 8-200Combined demand factor — the 3,000 VA threshold at 100%, remainder at 35%
Rule 8-208 + Table 14Electric range demand — table-based, not full nameplate
Rule 8-210Electric dryer — minimum 5,000 VA or nameplate, whichever is greater

This calculator covers CEC Part II (residential) only — dwellings up to two units on a single service. Commercial, industrial, and multi-unit residential buildings require CEC Part I calculations with different demand factors.

Your inputs — what each field means

InputCEC RuleWhat it means
Heated floor area (m²)Rule 8-202The total heated floor area of the dwelling. Used to calculate the basic load — the minimum panel capacity for general lighting and outlets.
Small appliance circuitsRule 8-204The number of 20A kitchen/dining circuits. The minimum is 2. Each adds 1,500 VA to the calculated load.
Electric dryerRule 8-210If present, adds max(5,000 VA, nameplate) to the service load at 100%.
Electric rangeRule 8-208, Table 14Range demand is not the nameplate wattage — it uses CEC Table 14. Ranges up to 12 kW nameplate use a demand of 8,000 VA. Above 12 kW: 8,000 + 400 × (kW − 12).
Water heater, fixed appliancesRule 8-200Added at 100% of nameplate. Includes dishwashers, freezers, garburators, and other fixed appliances.
Electric heatingRule 8-200Added at 100%. If both heating and cooling are electric, only the larger of the two is included — not both simultaneously.
Air conditioningRule 8-200Added at 100% if it is larger than the heating load. Only one is included per the CEC — a home is never heating and cooling at the same time.

The calculation — step by step

  1. Basic load (Rule 8-202):
    5,000 VA + (1,000 VA × number of additional 90 m² units)
    For a 200 m² home: 5,000 + ceil((200−90)/90) × 1,000 = 5,000 + 2 × 1,000 = 7,000 VA.
  2. Small appliance load (Rule 8-204):
    1,500 VA × number of small appliance circuits
    Minimum 2 circuits: 2 × 1,500 = 3,000 VA.
  3. Combined demand (Rule 8-200):
    first 3,000 VA × 1.0 + remaining VA × 0.35
    Example: basic + small appliance = 10,000 VA → demand = 3,000 + 7,000 × 0.35 = 5,450 VA.
  4. Add fixed loads at 100%: Dryer (at demand VA), range (at Table 14 demand), water heater, fixed appliances.
  5. Add heating or cooling (whichever is larger) at 100%.
  6. Total service load:
    total VA ÷ 240V = service amps
    Rounded up to the next standard service size: 100A, 125A, 150A, 200A, or 400A.

Reading your result

  • Basic load VA: The floor area contribution from Rule 8-202.
  • Small appliance VA: Kitchen circuit contribution from Rule 8-204.
  • Demand VA: The combined general load after the 35% demand factor is applied.
  • Total VA: Sum of all loads — demand, dryer, range, fixed, and heating or cooling.
  • Total amps: Total VA ÷ 240V. This is the value on the permit application.
  • Required service size: The next standard panel size above the calculated amps — 100A, 125A, 150A, 200A, or 400A.

Assumptions and limitations

  • Uses 240V single-phase service, which covers all standard Canadian residential services.
  • CEC Part II residential only — does not cover apartments, commercial occupancies, or buildings requiring Part I calculations.
  • Does not apply provincial amendments to the CEC. In most provinces, the residential demand method is identical to the base CEC. Confirm with your provincial AHJ if in doubt.
  • Does not include EV charger loads as a separate fixed load — if you have or plan a Level 2 EV charger (typically 7,200W at 240V/30A), add it to the “other fixed appliances” field.

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