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CSA C861-10 (R2015): Performance Requirements for Electric Storage Tank Water Heaters
A comprehensive guide to the Canadian standard for testing, rating, and certifying electric storage tank water heaters
CSA C861-10 (R2015), issued by the Canadian Standards Association, establishes uniform test methods and performance criteria for electric storage tank water heaters. Reaffirmed in 2015, this standard is referenced by Canadian federal and provincial energy efficiency regulations. It defines how manufacturers determine the energy factor (EF) and standby loss (SL) of residential electric water heaters, ensuring fair comparison and compliance with Canada’s energy efficiency targets. This article provides a detailed overview of the standard’s scope, technical requirements, implementation considerations, and compliance pathways.
1. Scope and Applicability
CSA C861-10 applies to all electric storage tank water heaters intended for residential and light commercial use, with rated storage capacities up to 227 L (50 gal). The standard covers single-phase and three-phase units, both with and without integral heat pumps, as long as the primary heating source is electric resistance. It does not cover gas-fired, solar, or tankless water heaters. The standard serves as the basis for determining energy performance metrics required under Canada’s Energy Efficiency Regulations, making it mandatory for products sold in Canada.
The standard defines two primary metrics:
- Energy Factor (EF): The ratio of useful energy delivered to the total energy consumed by the water heater over a 24-hour simulated use period.
- Standby Loss (SL): The rate of heat loss from the stored water during non-use periods, measured in watts or as a percentage of tank capacity.
Both metrics are derived from a standardized test procedure that simulates typical household hot water usage patterns.
Tip: CSA C861-10 is harmonized with the U.S. DOE test procedure (10 CFR Part 430, Appendix E) for electric water heaters, but uses SI units and Canadian voltage/frequency standards. Ensure your test lab is familiar with these differences.
2. Technical Requirements
2.1 Test Conditions
The test requires a controlled environment with specified water supply temperature, ambient temperature, and applied voltage. Key parameters are summarized in Table 1.
| Parameter | Specification | Notes |
|---|---|---|
| Inlet water temperature | 14°C ± 0.5°C | Measured at inlet connection |
| Ambient air temperature | 20°C ± 1°C | Measured 1 m from heater |
| Supply voltage | 240 V (nominal) for single-phase; 208 V for 3-phase | Maintained within ±1% |
| Water density and specific heat | 1.0 kg/L, 4.186 kJ/(kg·K) | For energy calculations |
2.2 Simulated Use Profile and Energy Factor
The test procedure simulates 64.3 L (17 gal) of hot water usage per day, distributed over six equal draws of 10.7 L (2.83 gal) each. The draws occur at hours 0, 1, 2, 3, 4, and 5 during a 24-hour period. The water heater’s thermostats are set to deliver water at 57°C (135°F) at the outlet. Energy consumption is continuously measured, and the EF is calculated as:
EF = Q_out / Q_in
where Q_out is the energy contained in the delivered hot water above the inlet temperature, and Q_in is the total electrical energy consumed (including controls, elements, and recovery). The test includes a 24-hour standby period after the draws to measure standby loss.
2.3 Standby Loss Calculation
Standby loss is determined from the temperature decay of the tank after the final draw cycle. The cooling curve is measured over a minimum of 12 hours, and the rate of heat loss is extrapolated to the standard temperature difference between stored water (57°C) and ambient (20°C). The standby loss is expressed both in watts (SL) and as a percentage of tank capacity per hour (% loss/h). CSA C861-10 sets maximum standby loss limits based on tank volume, as shown in Table 2.
Important: Standby loss limits are more stringent for larger tanks. Products exceeding these limits cannot be certified under the standard and are ineligible for the ENERGY STAR® label in Canada.
| Rated Storage Volume (L) | Maximum Standby Loss (%/h) | Maximum Standby Loss (W) |
|---|---|---|
| ≤ 50 | 0.85 | ≤ 20 |
| 51–100 | 0.75 | ≤ 25 |
| 101–150 | 0.65 | ≤ 35 |
| 151–227 | 0.55 | ≤ 45 |
3. Implementation Highlights
3.1 Laboratory Setup
Testing facilities must ensure stable environmental conditions, with precise control of ambient and inlet water temperature. The water supply must be conditioned to ±0.5°C before entering the test unit. The heater is equipped with internal temperature sensors at multiple heights, and power meters with ±1% accuracy measure energy input. Data acquisition systems record temperatures, power, and flow rates every 10 seconds.
3.2 Measurement Procedures
Before the test, the water heater is allowed to stabilize with the thermostat set to 57°C. A pre-test conditioning period ensures uniform temperature throughout the tank. The six draws are performed with a flow rate of 3.0 L/min ± 0.3 L/min. The outlet temperature is recorded during each draw, and the total energy delivered is integrated from the temperature rise and volume. Standby cooling is monitored with no draws for at least 12 hours following the last draw.
Best Practice: Use insulated tank wraps and minimize thermal bridges (e.g., fittings, pipes) during the test to isolate the tank’s inherent standby performance. Calibrate all thermocouples annually against a traceable reference.
3.3 Calculation and Reporting
The energy factor and standby loss are computed using the formulas in Annex A of the standard. Results must be rounded to three significant figures and reported on the compliance label. The standard also requires reporting the recovery efficiency (RE) and first-hour rating (FHR) to assist consumers in sizing. All data must be maintained for a minimum of five years after testing.
4. Compliance and Certification
Manufacturers seeking to sell electric storage tank water heaters in Canada must demonstrate compliance with CSA C861-10 through testing by an accredited third-party laboratory. Certified products are listed on the NRCan database and permitted to display the CSA or equivalent certification mark. The standard is referenced in the Canadian Energy Efficiency Regulations, making compliance mandatory. Regular audits and verification testing are conducted by certification bodies to ensure ongoing conformity.
Non-compliance consequences: Products failing to meet the EF or SL limits may be banned from sale in Canada, with penalties for each violation. Retesting and re-certification are required if design changes affect performance.
Updates to CSA C861 are under periodic review; the R2015 reaffirmation maintains the 2010 requirements. However, manufacturers should monitor the CSA group for upcoming revisions that may align with updated Canadian efficiency targets, such as those stemming from the Pan-Canadian Framework on Clean Growth and Climate Change.
Q: Who must comply with CSA C861-10 (R2015)?
A: Any manufacturer or importer of residential electric storage tank water heaters with capacities up to 227 L that are sold in Canada. The standard is referenced in federal energy efficiency regulations, making compliance mandatory. Certification is required before products can be marketed or sold.
A: Any manufacturer or importer of residential electric storage tank water heaters with capacities up to 227 L that are sold in Canada. The standard is referenced in federal energy efficiency regulations, making compliance mandatory. Certification is required before products can be marketed or sold.
Q: How does CSA C861-10 differ from the US DOE test procedure for electric water heaters?
A: Both are largely harmonized in terms of draw pattern and EF calculation. However, the Canadian standard uses 14°C inlet temperature instead of 58°F (14.4°C), a 57°C outlet temperature instead of 135°F (57.2°C), and specifies supply voltages of 240 V / 208 V. The standby loss limits and metric presentation (SI units) also differ.
A: Both are largely harmonized in terms of draw pattern and EF calculation. However, the Canadian standard uses 14°C inlet temperature instead of 58°F (14.4°C), a 57°C outlet temperature instead of 135°F (57.2°C), and specifies supply voltages of 240 V / 208 V. The standby loss limits and metric presentation (SI units) also differ.
Q: Can a water heater with a heat pump component be tested under this standard?
A: The standard applies primarily to electric resistance storage heaters. For units with integrated heat pumps (i.e., hybrid water heaters), CSA C861 is not the primary standard; instead, CSA C745 or the CSA C861-series amendment for heat pumps should be used. Check with a certification body for the applicable test method.
A: The standard applies primarily to electric resistance storage heaters. For units with integrated heat pumps (i.e., hybrid water heaters), CSA C861 is not the primary standard; instead, CSA C745 or the CSA C861-series amendment for heat pumps should be used. Check with a certification body for the applicable test method.
Q: What are the consequences of non-compliance?
A: Sale of non-compliant water heaters is prohibited in Canada. Offenders may face fines, removal of products from the market, and damage to regulatory standing. Retesting and re-certification are mandatory before resuming sales.
A: Sale of non-compliant water heaters is prohibited in Canada. Offenders may face fines, removal of products from the market, and damage to regulatory standing. Retesting and re-certification are mandatory before resuming sales.
Article content is for informational purposes and does not substitute for the official standard. Consult CSA Group for the authoritative document. Last updated 2026.