If your LPG is disappearing faster than it used to, something has changed — and it's worth finding out what before your next bottle runs dry at the worst possible moment. The cause could be as simple as colder weather or a new appliance, or as serious as a gas leak that needs urgent attention. Here's how to work through the possibilities safely.
Check for an Obvious Gas Leak First
Before anything else, safety comes first. If you can smell gas (a strong rotten-egg or sulphur odour), act immediately:
- Don't operate any switches, flames, or electrical devices.
- Ventilate the area by opening doors and windows.
- Turn off the gas at the cylinder valve.
- Leave the building and call your gas supplier or 111 if you suspect a serious leak.
Even a small, slow leak you can't smell can waste significant amounts of LPG over days or weeks. A licensed gasfitter can perform a pressure drop test on your system to confirm whether gas is escaping somewhere it shouldn't be. This is not a DIY test — it requires calibrated equipment and is work that must be carried out by a licensed gasfitter registered with the PGDB.
Common Reasons LPG Usage Increases
1. A Gas Leak in the System
Leaks can occur at cylinder connections, flexible hoses, regulators, appliance fittings, or buried pipework. Rubber hoses and O-rings degrade over time, especially outdoors in NZ's UV-intense sunlight. Even a pinhole leak at a fitting can drain a 45 kg cylinder noticeably faster than normal.
2. A Faulty or Worn Appliance
Appliances that aren't burning efficiently use more gas to achieve the same result. Common culprits include:
- Water heaters with a pilot light that's burning too rich, or a heat exchanger that's scaled up.
- Gas heaters with blocked burners or dirty filters forcing them to run longer.
- Cooktops with burners that don't ignite cleanly and waste gas before lighting.
If an appliance is running noticeably longer to do the same job, or the flame colour has changed (healthy gas flames are mostly blue; yellow or orange flames suggest incomplete combustion), have a licensed gasfitter inspect it.
3. Regulator Problems
The regulator controls the pressure of gas flowing from the cylinder to your appliances. A faulty regulator can allow gas to flow at higher-than-normal pressure, increasing consumption across every appliance connected to it. Regulators have a service life — check with your gas supplier how old yours is. Regulator replacement must be carried out by a licensed gasfitter.
4. Seasonal and Weather Changes
LPG consumption naturally rises in winter. Gas heaters, hot water systems, and log-effect fires all work harder when temperatures drop. New Zealand's colder southern regions and high-altitude areas can see dramatic seasonal swings. If your usage has crept up gradually as the weather has cooled, this may simply be normal — but it's still worth benchmarking against the same period last year.
5. Household Changes
Think about what's changed at home:
- More people living in the house?
- A new gas appliance installed (spa pool heater, second heater, outdoor BBQ connected to the main supply)?
- Longer showers or more frequent cooking?
Sometimes the answer is behavioural rather than mechanical.
6. Cylinder or Gauge Inaccuracy
LPG cylinders are filled by weight, not volume. If you're relying on a gauge, be aware that cheap magnetic gauges can be unreliable, especially in cold weather when LPG pressure drops. Weigh your cylinder on bathroom scales (subtract the tare weight stamped on the collar) to get an accurate reading of how much gas remains.
What You Can Safely Check Yourself
As a homeowner, there are a few things you can do without needing a tradesperson:
- Soap-bubble test at the cylinder connection: Apply soapy water to the regulator connection and cylinder valve with the gas on. Bubbles indicate a leak. If you find one, turn off the gas and call a gasfitter — don't try to repair fittings yourself.
- Check appliance flames: Look for yellow or orange flames, which suggest incomplete combustion.
- Review your usage history: Note how many cylinders you've used over the past few months compared to the same period in previous years.
- Inspect flexible hoses visually: Look for cracking, kinking, or UV damage on any exposed rubber hoses. Don't use the appliance if hoses look deteriorated — call a gasfitter.
Do not attempt to disassemble regulators, refit gas connections, or repair any pipework yourself. Under the Gas Act 1992 and NZ Building Code, gasfitting work is restricted to licensed practitioners registered with the Plumbers, Gasfitters and Drainlayers Board (PGDB).
When to Call a Professional
Call a licensed gasfitter if:
- You suspect a leak anywhere in the system.
- Your appliances have yellow or orange flames, or are running longer than usual.
- You notice a hissing sound near the cylinder or pipework.
- Your regulator is old or has never been serviced.
- You can't identify a clear reason for the increased usage after checking the basics.
A gasfitter will carry out a full pressure test, inspect all appliances and connections, and certify any work completed. You can find qualified local gasfitters on tradedirectory.co.nz.
For general guidance on energy efficiency and reducing gas consumption at home, Energywise has useful resources. For safety standards and what qualifies as restricted gasfitting work, refer to WorkSafe NZ and MBIE Building Performance.
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