The Problem: High Gas Bills That Didn't Add Up
The client noticed their gas bills had been climbing steadily over the past year without any obvious explanation. Usage habits hadn't changed — same household, same appliances. When we arrived to inspect, the source became clear almost immediately.
The existing hot water unit was a storage-style gas system that had been in service for well over a decade. Older storage systems keep a full tank of water at temperature 24 hours a day, 7 days a week — regardless of whether anyone is actually using hot water. As internal components wear and efficiency ratings drop with age, these units consume significantly more gas to maintain that standby temperature. It's one of the most common causes of unexplained high gas bills that we see.
What You're Looking At
The photo shows the new Thermann instantaneous gas hot water unit installed cleanly on the exterior brick wall. Unlike a storage system, there's no tank — the unit is compact, wall-mounted, and only fires when a hot tap is opened. Once demand stops, it shuts off completely. No standby heat loss, no wasted gas.
The installation included new gas and water connections, proper flue and exhaust routing, and full commissioning to confirm correct temperature settings and flow rate before we left the job.
Why Instantaneous Gas Outperforms Storage
A storage system keeps 160–250 litres of water hot at all times. An instantaneous unit heats water only when you open a tap — and stops the moment you close it. That difference alone accounts for a substantial share of the gas saving.
A storage system can run out if multiple people shower in succession. An instantaneous unit has no tank to deplete — it can supply continuous hot water for as long as you need it, at a consistent temperature.
Storage systems require significant wall or floor space for the tank. The Thermann unit occupies a fraction of that space — wall-mounted on the exterior, out of the way, and leaving usable space in your laundry or utility area.
With no tank subject to constant pressure and temperature cycling, instantaneous units typically outlast storage systems when properly maintained. Fewer moving parts under sustained thermal stress means fewer failures over time.
A lot of households change gas retailers when bills spike, then wonder why nothing improves. If your hot water system is 10+ years old and running inefficiently, no tariff change will offset what the unit is consuming. Get the system assessed first.
About the Thermann Instantaneous Range
Thermann is an Australian brand with a solid track record in the residential gas hot water market. Their instantaneous units are available in multiple flow rate configurations to suit different household sizes, carry a manufacturer's warranty, and parts are widely available nationally — which matters when you need a repair down the track.
For this Pascoe Vale property, we sized the unit to the household's peak demand so there's no risk of running short during a busy morning. Temperature was set at 50°C at the unit with mixing valve protection — safe for children and compliant with current Victorian plumbing regulations.
Pascoe Vale 3044 falls within the City West Water service area. Hot water system replacements must be performed by a licensed plumber and gasfitter. We hold a current VBA licence and are fully insured — ask us for details when you call.
How We Approached This Installation
- Inspected and tested the existing storage hot water unit — confirmed inefficiency and age-related performance decline
- Removed the old storage system and capped existing connections safely
- Installed the new Thermann instantaneous unit on the exterior brick wall with appropriate brackets and fixings
- Connected new gas line with correct sizing for the unit's flow rate requirements
- Routed the exhaust flue to comply with clearance requirements from windows and eaves
- Commissioned the unit, confirmed ignition and modulation, set outlet temperature
- Tested all hot water outlets throughout the home — consistent temperature and flow confirmed
High Gas Bills or an Ageing Hot Water System?
We'll assess your current setup honestly — if a replacement will save you money, we'll tell you. If it won't, we'll tell you that too.