Which water heaters are made for outside
Several types are designed for outdoor installation. Rinnai has mains pressure cylinders made for indoor or outdoor use. Rheem's gas range includes the Stellar outdoor gas storage heater, which runs on natural gas only.
A heat pump water heater draws warmth from the air, so it needs outdoor space. Rheem points out that switching to one can mean relocating the cylinder. Rinnai sells both integrated and split heat pump models, so ask which layout suits your space.
A cylinder built for indoors isn't automatically fine outside. Check that the model you're looking at is made for it. Every type is covered on our hot water cylinders page.
Is outdoors right for your home?
- You want the cupboard space back for storage or a bigger bathroom.
- You're moving to a heat pump or a gas heater designed for outside.
- There's a wall or pad close to the existing pipes, power or gas.
- The spot is easy for a tradie to reach later.
- It won't sit right under a bedroom window, yours or the neighbours'.
What changes when it moves outside
Relocating a cylinder means new pipe runs, a new electrical or gas connection, a base or wall fixing, and somewhere for the valves to drain. A plumber will plan those around the spot you choose.
The Building Code still expects the installation to avoid leaks, give reasonable access to parts that need maintenance, and allow the system to be isolated for testing. Rheem's installation guide also calls for seismic restraints, wherever the cylinder ends up.
Consent and who does it
Under Schedule 1 clause 38 of the Building Act, replacing a water heater is exempt from building consent, and that explicitly includes repositioning an existing one. The conditions: the replacement is connected to, or incorporates, a controlled heat source, and an authorised person does the work. The finished installation must still comply with the Building Code.
Other building work around a new outdoor spot, such as an enclosure, is a separate question, so raise it with your installer or the council. The plumbing needs an authorised plumber, the power an electrician, and any gas an authorised gasfitter.
Groundwork you can do
You can
- Pick two or three possible spots and photograph them.
- Check there's a clear path for getting the cylinder in and servicing it later.
- Let neighbours know if a unit will sit near their boundary.
- Note where the switchboard and gas meter are.
Leave to an authorised tradie
- Choosing and preparing the base or wall fixing.
- New pipe runs, valves and their drains.
- The electrical connection (an electrician) or gas (an authorised gasfitter).
- Restraint, access and weather protection.
Ask the installer
- Is this model made for outdoor installation?
- How will the pipes be protected from the weather and from knocks?
- Where will the relief valve drain to?
- Does moving it change anything for consent?
- How will it be restrained?
What we would do
Choose the spot with the tradie, not before they arrive. The right outdoor position keeps pipe runs short, leaves room to service the unit, and suits the maker's instructions. Ask an installer who moves cylinders outside regularly to walk the section with you before you buy.