Do you need a building consent for a new hot water system in NZ? (2026 guide)

Whether you need a building consent for a new hot water system depends on what you're doing: building a new home, replacing an existing water heater, or adding to one. Here's how the rules work in New Zealand in 2026.

Building a new home

Your hot water system will be shown on your plans and included in the building consent for the whole house. We'll give you the product documents for your Energie solar thermodynamic system to include with your application.

Replacing or moving an existing water heater

No consent is needed. Exemption 38 of Schedule 1 of the Building Act lets an authorised plumber replace or move a water heater without a building consent, as long as every heat source connected to it is "controlled". A controlled heat source keeps the stored water at no more than 90°C.

MBIE gives these examples of exempt work:

• replacing a water storage heater with a heat pump water storage heater
• replacing an internal cylinder with an external heat pump system
• replacing an electric or gas cylinder with one that has controlled solar collectors

The exemption doesn't cover uncontrolled heat sources, such as a wetback connected to a wood burner.

Adding to an existing cylinder

Adding solar collectors or a split heat pump to a cylinder you're keeping needs a building consent, even if the cylinder has a solar connection. Alternatively, you can ask your council for a discretionary exemption. Talk to the council first.

What about the panel on the roof?

Since 23 October 2025, roof-mounted solar panel arrays under 40 m² in wind zones up to "high" don't need a building consent. Larger arrays, or those in very high wind zones, need a design by a Chartered Professional Engineer. Our solar thermodynamic panels are well within the size limit: one panel, weighing about 8kg, is enough for most households of up to five people. You still need to meet the Building Code and your district plan.

Who does what

• You (the homeowner) apply for consent if one is needed. We provide the documents to support your application.
• An authorised plumber connects the cylinder.
• TAEC installs the solar thermodynamic panel and connects it to the system.

Not sure which applies to you? Try MBIE's Can I Build It? tool, check with your local council, or contact us or call 03 540 3003 and we'll help you work it out. See also our FAQs.

This is general guidance and not legal advice. Always check with your council before starting building work.