Quick answer:The Rheem Optima 300L is a large outdoor mains pressure electric hot water cylinder — $4,999 incl GST fully installed across Auckland by Water & Gas Worx. Suits households of 4+ people or homes with multiple bathrooms. Price includes the unit, removal of your old cylinder, plumbing connections, mains pressure valve pack, electrical reconnection, and Rheem warranty registration. Installed by Peter — licensed plumber. Call 0800 322 322.
About the Rheem Optima 300L
The Rheem Optima 300L is the largest outdoor-rated electric cylinder in the Rheem range — built for large families and homes with multiple bathrooms. At 300 litres, it stores enough hot water to supply five people through a full morning routine without the element needing to recover between uses. Like the 180L, it carries the weatherproof outdoor jacket that makes it suitable for external wall and ground-level installation.
Vitreous enamel construction and a 10-year cylinder warranty make the Optima 300L a long-term investment. At 1,480 mm tall and 570 mm in diameter, it is a substantial unit — we confirm clearances and structural suitability before installation, and quote any additional groundwork or wall-reinforcement required. For properties where internal cupboard space simply does not accommodate a large cylinder, this outdoor model solves the problem completely.
We install Rheem Optima 300L cylinders throughout Auckland — West Auckland, North Shore, Manukau, and the eastern suburbs. The job typically takes four to six hours for a direct swap. If you are upgrading from a smaller unit and need larger-diameter connection work, we factor this into the quote. There are no surprises on the day.
Technical Specifications
| Capacity | 300 litres |
| Type | Mains pressure, outdoor-rated |
| Element | 3.6 kW |
| Material | Vitreous enamel |
| Warranty | 10-year cylinder, 2-year parts |
| Dimensions (H × dia) | 1,480 mm × 570 mm |
| Weight (empty) | 75 kg |
| Recovery rate | ~135 L/hr at 40°C rise |
| Suitable for | 5+ people |
Why This Unit for Auckland?
- — Installed across Auckland since 2009 — we know these units and the conditions they run in
- — Fixed pricing with no surprises — what we quote is what you pay
- — Licensed plumber and gasfitter — all certification included
- — Same-week installation available in most Auckland suburbs
- — Old unit disconnected, removed, and disposed of — nothing left for you to deal with
Frequently Asked Questions — Rheem Optima 300L
What is the Rheem Optima 300L installed price in Auckland?
The Rheem Optima 300L is $4,999 incl GST fully installed. This includes the unit, removal of the old cylinder, plumbing connections, mains pressure valve pack, electrical reconnection, and warranty registration.
Who is the Rheem Optima 300L suited for?
Households of five or more people, or homes with multiple bathrooms where two or more people regularly shower at similar times. If you find your current cylinder runs out of hot water before everyone has showered, the 300L resolves this without switching to continuous flow.
How tall is the Rheem Optima 300L?
The Optima 300L stands 1,480 mm tall and is 570 mm in diameter. It weighs 75 kg empty and approximately 375 kg full. Position and structural mounting points need to be checked before installation — we do this on every job.
Can the Rheem Optima 300L be wall-mounted?
The Optima 300L can be wall-mounted with appropriate heavy-duty brackets and adequate wall structure, or ground-mounted on a concrete pad or steel stand. At full capacity it weighs close to 375 kg, so the mounting surface must be engineered to support this load. We assess this during the site inspection.
Is the Rheem Optima 300L available for natural gas areas and LPG areas?
The Optima is an electric cylinder, not gas-fired. It runs on a standard 240V electrical supply. If you are currently on gas hot water and considering switching to electric, we can quote the full transition including gas line capping.
How long does a Rheem Optima 300L installation take?
A standard swap from an existing outdoor cylinder takes four to six hours. Larger plumbing modifications or ground-mounting work may extend this to a full day. We advise on timing when we quote.
What warranty does the Rheem Optima 300L carry?
Rheem provides a 10-year cylinder warranty and a 2-year warranty on parts including the element and thermostat. We register the warranty with Rheem NZ on the day of installation.
