Most Newcastle homeowners have their hot water system replaced once, maybe twice over the life of a property. Knowing what the installation process looks like — what the plumber will do, how long it takes, what disruption to expect, and what you need to do — helps the day go smoothly and avoids surprises.
Before Installation Day
Choosing the Right System
The first step happens before installation day — choosing the right replacement system. Key decisions: gas vs electric vs heat pump vs solar; system size (capacity in litres for storage, flow rate in L/min for continuous flow); brand; and location (same spot or relocated).
For emergency replacements where hot water has failed, you may be making this decision under pressure. Our recommendation: have the broad preference (gas continuous flow if you have gas; heat pump if no gas and space available; electric storage if budget is the constraint) decided in advance so you're not choosing cold under pressure.
Access and Preparation
Ensure clear access to the hot water system location and the water meter (the plumber will need to turn water off at the meter during the installation). If the system is in a laundry or bathroom, clear any items around it. If it's in a roof space or crawl space, confirm the plumber can access it safely.
Installation Day: Step by Step
1. Water Off (5 minutes)
The plumber turns water off at the main meter. This affects all water in the house — plan bathroom use before the plumber arrives. Water is typically off for 60–90 minutes for a straightforward replacement.
2. Old System Isolation and Draining (20–30 minutes)
The existing system is isolated from the water supply, the tank is drained (a full 250L storage tank takes 20–30 minutes to drain), and the electrical or gas connection is isolated. For a gas system, the gas is turned off at the system isolation valve.
3. Old System Removal (15–30 minutes)
The old unit is disconnected from supply, gas/electrical, and any drainage connections, and removed. For roof-mounted solar systems, this involves roof access — more complex and time-consuming. Ground-level systems are typically straightforward.
4. New System Connection (45–90 minutes)
The new system is positioned, levelled, and connected to cold water supply, hot water outlet, and gas/electrical supply. For gas units, the gas connection is pressure tested before any gas valves are opened. Flexible connections and pressure-limiting valves are checked or replaced as required.
For a continuous flow gas unit, the flue is connected and the unit is mounted to the wall. For a heat pump, the compressor unit is positioned outdoors and connected to the tank.
5. Commissioning and Testing (20–30 minutes)
Water is turned back on at the meter. All connections are checked for leaks under pressure. For gas systems, all gas connections are checked with leak detection solution. The system is powered on and temperature settings are confirmed. For storage systems, the tank begins heating — you won't have fully hot water until the tank has heated completely (1–3 hours depending on system type).
6. Documentation (10 minutes)
A Certificate of Compliance is issued for the installation. You receive the manufacturer's warranty documentation and the plumber walks you through basic operation — particularly temperature settings, the pressure relief valve discharge location, and any periodic maintenance requirements.
Total Timeframes by System Type
| System Type | Installation Time | Time to First Hot Water |
|---|---|---|
| Electric storage (like-for-like) | 2–3 hours | +1–3 hours tank heat-up |
| Gas continuous flow (like-for-like) | 2–3 hours | Immediate |
| Gas continuous flow (new gas line) | 3–5 hours | Immediate |
| Heat pump | 3–5 hours | +3–4 hours first heat-up |
| Solar (roof panels + tank) | 5–8 hours | Next day (first solar cycle) |
What the Plumber Needs From You
- Access to the water meter and the hot water system location
- Decision on system type and size (confirm before arrival)
- For heat pump: confirmed outdoor installation location and clearances
- For solar: roof inspection access and preferred tank location
- Confirmation of whether off-peak tariff is available (for storage systems)
Do I need to be home during hot water system installation in Newcastle?
Yes — the plumber needs access to the property and will need to walk you through the commissioning at the end. You'll need to sign off on the installation and receive the documentation. For the bulk of the installation time (1–2 hours), you don't need to actively supervise, but being present at start and finish is required.
Will there be any mess after hot water system installation?
Minimal for a straightforward replacement. Draining the old tank produces water that goes to a garden or laundry drain — no mess indoors. The old unit is removed from site (included in our installation service). The installation area may have minor water marks from connection work, which clean up easily. For roof-mounted systems, there may be slight debris from roof access — this is cleaned up before we leave.
📞 Need a plumber in Newcastle? Call 0491 570 006 for same-day service across Newcastle and the Hunter region.