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Understanding CSA C748-13 (2018): Performance Requirements for Electric Storage Tank Water Heaters
A comprehensive guide to the Canadian standard for energy efficiency and performance of residential electric water heaters
Scope and Application
CSA C748-13 (2018) is the third edition of the Canadian standard titled “Performance of electric storage tank water heaters.” This standard establishes minimum energy efficiency requirements and test methods for factory‐built electric storage tank water heaters intended for residential and light commercial applications. It applies to heaters with a storage capacity up to 454 L (120 US gal) and a rated input of 12 kW or less, designed to operate at a nominal voltage of 120 V to 600 V.
The standard covers both vertical and horizontal models, as well as those intended for indoor or outdoor installation. It does not apply to instantaneous (tankless) water heaters, heat pump water heaters, or non‐electric storage water heaters. The primary objective is to reduce standby heat losses and improve overall energy performance, thereby contributing to Canada’s energy conservation goals.
Key Update: CSA C748-13 (2018) supersedes the 2010 edition. The most notable changes include revised standby loss test conditions for larger tanks and updated calculation methods for standby loss factor (SLF) to align with more recent testing practices.
Technical Requirements and Performance Metrics
Standby Loss Requirements
The central performance metric in CSA C748-13 (2018) is the standby loss factor (SLF), expressed in watts (W). It represents the rate of heat loss from the stored water when the heater is not actively heating. The standard mandates that the measured SLF must not exceed a maximum allowable value calculated from the tank’s rated storage volume.
| Rated Volume (L) | Maximum Allowable Standby Loss (W) |
|---|---|
| ≤ 190 | 67 |
| 191 – 285 | 77 |
| 286 – 380 | 87 |
| 381 – 454 | 97 |
Note: Values shown are for tanks insulated with foam and equipped with automatic controls. For tanks with glass‐lined or other internal coatings, the manufacturer must demonstrate compliance through the prescribed test procedure.
Test Conditions and Measurement
Testing must be conducted at an ambient temperature of 20 ± 2 °C and a water temperature of 57.2 °C (135 °F). The heater is operated until steady‐state is achieved, then the energy input required to maintain the setpoint over a period of 24 hours is measured. The standby loss factor is calculated as the average input power during the test period, corrected for any electrical input to controls or pumps.
Tip: When preparing for certification, ensure the test facility meets the environmental control requirements specified in Clause 7 of the standard. Fluctuations in ambient temperature or water supply temperature can significantly affect repeatability.
Product Marking and Documentation
Each water heater covered by this standard must be permanently marked with the rated volume, rated input, maximum allowable standby loss, and the manufacturing date. Installation instructions must include a statement that the appliance meets the requirements of CSA C748-13 (2018).
Compliance and Implementation
Conformity Assessment
Compliance with CSA C748-13 (2018) is typically demonstrated through third‐party certification by an accredited body such as CSA Group or Intertek. The manufacturer submits a representative sample for testing, and if all requirements are met, a report and certificate are issued. Periodic factory audits are required to maintain certification.
Warning: Self‐declaration of compliance without third‐party testing is not generally accepted by Canadian regulatory authorities. Many provinces and territories mandate that electric storage water heaters sold or installed must bear a recognized certification mark.
Adoption in Canadian Regulations
CSA C748-13 (2018) is referenced by the Energy Efficiency Regulations under the Canadian Environmental Protection Act, 1999. It is also invoked in the National Building Code of Canada and various provincial plumbing codes. Therefore, compliance is effectively mandatory for all products offered for sale in Canada.
Implementation Challenges
- Insulation optimization: Meeting the standby loss limits may require thicker foam insulation or advanced jacket designs, increasing product cost.
- Control system interactions: The standby loss measurement excludes energy consumed by electronic controls or timers. Manufacturers must ensure these components do not inadvertently inflate measured standby loss during the test.
- Production variability: Tolerances in tank assembly and foam application can cause unit‐to‐unit variation. Periodic in‐plant verification testing is essential.
Success Factor: Manufacturers that integrate energy efficiency into the design phase often find that compliance becomes a market advantage. Products that exceed the minimum requirements can qualify for voluntary energy efficiency labels (e.g., ENERGY STAR Canada).
Frequently Asked Questions
Q: Does CSA C748-13 (2018) apply to heat‐pump water heaters?
A: No. This standard specifically covers electric resistance storage tank water heaters. Heat‐pump water heaters are covered under CSA C749 (for pack‐aged units) or separate performance specifications.
A: No. This standard specifically covers electric resistance storage tank water heaters. Heat‐pump water heaters are covered under CSA C749 (for pack‐aged units) or separate performance specifications.
Q: How often is the standard updated?
A: CSA C748 is periodically reviewed every five years. The 2018 edition supersedes C748-13 and the 2008 edition. Future updates may incorporate energy efficiency levels aligning with US Department of Energy requirements.
A: CSA C748 is periodically reviewed every five years. The 2018 edition supersedes C748-13 and the 2008 edition. Future updates may incorporate energy efficiency levels aligning with US Department of Energy requirements.
Q: Can I use a water heater that does not meet CSA C748 for replacement of an existing unit?
A: Typically, new installations and replacements must comply with the current standard in effect at the time of installation. Some jurisdictions may allow grandfathering of existing units, but a non‐compliant replacement is generally not permitted.
A: Typically, new installations and replacements must comply with the current standard in effect at the time of installation. Some jurisdictions may allow grandfathering of existing units, but a non‐compliant replacement is generally not permitted.
Q: What is the relationship between CSA C748-13 (2018) and the Canadian Electrical Code?
A: The Canadian Electrical Code (CE Code) sets safety requirements for electrical equipment, while CSA C748 addresses energy performance. A product must comply with both the CE Code (e.g., CSA C22.2 No. 64 for water heater safety) and the performance standard before it can be certified and sold in Canada.
A: The Canadian Electrical Code (CE Code) sets safety requirements for electrical equipment, while CSA C748 addresses energy performance. A product must comply with both the CE Code (e.g., CSA C22.2 No. 64 for water heater safety) and the performance standard before it can be certified and sold in Canada.
Disclaimer: This article provides a general overview of CSA C748-13 (2018) for informational purposes. For complete details, refer to the official standard published by CSA Group. Technical requirements and regulatory references are subject to change. Always verify with the latest official documents.
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