EECA’s proposed minimum energy performance standards for heat pump hot water cylinders will likely eliminate up to 40% of current market models, forcing manufacturers to upgrade efficiency ratings or withdraw products entirely.
How to comply
It is a legal requirement for suppliers to register all heat pump hot water systems under the Energy Efficiency (Energy Using Products) Regulations 2002 before sale in New Zealand. Registration must include verified performance data meeting the proposed coefficient of performance thresholds.
Heat pump efficiency thresholds
3.2
Air-source minimum COP
4.0
Ground-source minimum COP
40%
Models potentially excluded
6 months
Transition period
Standards applicable
Heat pump hot water cylinders must comply with AS/NZS 4234 testing protocols for energy efficiency measurement. Standards can be purchased from Standards New Zealand to verify compliance with the new MEPS framework.
Which products are included
The revised standards cover all electric heat pump systems integrated with storage cylinders, including split and integrated units with capacities from 160 litres to 400 litres. Both indoor and outdoor hot water cylinders fall within scope.
Which products are excluded
Gas-boosted heat pump systems and commercial units above 400 litres capacity remain outside the MEPS framework. Retrofit heat pump units for existing cylinder installations are also excluded from the initial rollout.
Performance requirements
According to EECA, the proposed minimum coefficient of performance stands at 3.2 for air-source models and 4.0 for ground-source systems. These thresholds align with Energy Star certification levels used in Australia.
NZ Building Code requirements
Heat pump hot water installations must meet Building Code Clause G12 for water supplies and Clause H1 for energy efficiency. Compliance requires verification that systems achieve the specified performance ratings under standardised test conditions.
Registration process
Suppliers must submit technical documentation through the Product Registration Database, including test certificates, energy labels and installation specifications. Non-compliant products face immediate withdrawal from the voluntary registry.
Market impact projections
Industry analysis suggests the standards will eliminate budget models with coefficient of performance below 3.0, potentially reducing consumer choice but driving down long-term running costs. Previous similar MEPS implementations for appliances saw 30-50% of existing models discontinued within 18 months.
Implementation timeline
The consultation period closes June 2026, with final standards taking effect from January 2027. Existing inventory can be sold until June 2027, providing a six-month transition period for retailers and installers.
New energy efficiency standards for electric hot water cylinders take effect in July 2026, requiring minimum insulation ratings of R-1.5 and mandatory thermostatic mixing valves for all new installations.
Minimum insulation requirements
Electric hot water cylinders installed after 1 July 2026 must achieve a minimum thermal resistance rating of R-1.5 for the cylinder body and R-2.0 for pipe connections within 1 metre of the cylinder. The insulation must maintain these values at operating temperatures up to 80°C.
Key compliance requirements
R-1.5
Minimum insulation rating
45°C
Maximum tap temperature
2.5 kWh/day
Maximum heat loss
±2°C
Temperature accuracy
600mm
Minimum access clearance
Manufacturers must provide performance data showing heat loss rates do not exceed 2.5 kWh per day for a standard 180-litre cylinder at 60°C ambient temperature. Testing must follow AS/NZS 4692.1 methodology under controlled laboratory conditions.
Note: Existing cylinders do not require immediate upgrade unless they are being replaced or undergo major modification work requiring building consent.
Temperature control standards
All new electric hot water cylinders must incorporate thermostatic mixing valves (TMV) — devices that blend hot and cold water to deliver consistent outlet temperatures. The TMV must be capable of maintaining outlet temperatures within ±2°C of the set point under varying supply pressures.
Water delivered to bathrooms and kitchens must not exceed 45°C at the tap. Cylinder storage temperature can reach 60°C to prevent Legionella bacteria growth, but mixing valves must reduce delivery temperature to safe levels.
Bathroom outlets: maximum 45°C
Kitchen outlets: maximum 45°C
Laundry outlets: maximum 50°C
Commercial dishwashers: maximum 60°C (with appropriate signage)
For example: A household cylinder storing water at 60°C must have a TMV that automatically mixes cold water to deliver 45°C water to shower and basin taps, regardless of whether someone opens another tap simultaneously.
Electrical safety compliance
Electric heating elements must comply with AS/NZS 3350.2.21 for household water heating appliances. Elements rated above 3.6 kW require dedicated circuits with appropriate overcurrent protection sized at 125% of the element rating.
Temperature and pressure relief valves must be installed within 150mm of the cylinder top connection and discharge through a visible tundish arrangement. Relief valve settings must not exceed 1000 kPa pressure or 99°C temperature.
According to Building Performance, all electrical work on cylinders requires certification by a registered electrician, with installation certificates provided to building consent authorities where required.
Note: Cylinder replacement in the same location typically does not require building consent, but electrical certification is still mandatory for new connections or circuit modifications.
Performance monitoring requirements
Cylinders must include digital temperature displays showing both storage and delivery temperatures. Display accuracy must be within ±1°C across the operating range of 10°C to 80°C. Displays must be visible without removing access panels or covers.
Smart cylinder controls — systems that can adjust heating schedules based on usage patterns or electricity pricing — become mandatory for cylinders larger than 250 litres. These systems must be capable of load shifting to off-peak periods while maintaining adequate hot water availability.
Energy consumption monitoring must record daily kWh usage with data accessible through manufacturer apps or web portals. Historical usage data must be retained for minimum 12 months to enable efficiency tracking.
Installation location standards
Indoor cylinders require minimum 600mm clearance on all sides for maintenance access. Outdoor installations must use cylinders specifically rated for external conditions with UV-resistant casing materials and additional insulation protection.
Cylinders installed in roof spaces must have permanent access routes capable of supporting removal and replacement equipment. Access hatches must be minimum 800mm x 800mm where cylinder diameter exceeds 600mm.
Note: Seismic restraints are mandatory in areas with seismic risk factor Z ≥ 0.13, requiring engineered fixing systems rated for horizontal loads of 1.8 times the cylinder’s filled weight.
Warranty and certification
Manufacturers must provide minimum 10-year warranties covering cylinder tanks and 5-year warranties for heating elements and electronic controls. Warranty terms must specify performance criteria including maximum acceptable heat loss rates and temperature control accuracy.
All cylinders require Water Mark certification demonstrating compliance with AS/NZS 3500.4.2 plumbing standards. Certification labels must remain permanently visible after installation and include QR codes linking to full specification documents.
For example: A cylinder warranty claim for excessive energy consumption requires usage monitoring data showing heat loss exceeding manufacturer specifications by more than 10% under standard operating conditions.
How to comply
Purchase cylinders displaying Water Mark certification and energy efficiency ratings meeting minimum R-1.5 insulation requirements
Ensure thermostatic mixing valves are installed and calibrated to deliver maximum 45°C water to bathroom and kitchen outlets
Engage registered electricians for all electrical connections and obtain required electrical certificates
Install digital temperature monitoring systems with visible displays and smart controls for cylinders over 250 litres
Provide adequate maintenance clearances and seismic restraints where building standards require them
