Gas Hot Water

Advantages of Gas Hot Water for Households

• No reliance on electricity: Gas systems continue working during power outages (assuming gas supply remains intact), giving continuity when electric supply is unreliable.
• Faster heat recovery & continuous supply: Gas cylinders can reheat water quickly — ideal for busy households with multiple hot-water uses.
• Cost-effective for larger families: For homes with multiple occupants and high hot-water demand, gas storage systems can be more economical than constantly running electric heaters.
• Space-saving options: Continuous-flow gas heaters are compact and don’t require large storage tanks, a benefit for homes with limited space.

Drawbacks & Considerations When Using Gas Heating

• Ventilation and safety requirements: Storage cylinders need proper ventilation and flues if installed indoors; ignoring this can lead to safety hazards.
• Maintenance requirements: Gas cylinders require more regular inspection and maintenance (e.g. checking valves, ensuring flues are clear) to prevent leaks, ensure safe operation, and prolong lifespan.
• Fuel price volatility: Running costs depend on gas pricing, which can fluctuate — making budgeting less predictable than using electricity or solar.
• Potential for system noise or delays (with instant systems): Continuous-flow heaters can have a short delay while heating up, which might be noticeable if a lot of hot water is demanded quickly.

Red Flags — Signs Your Plumbing or Cylinder Might Be Failing

If your water supply is chlorinated (or you suspect it might be), it’s wise to periodically inspect your plumbing and hot water system. Here are warning signs to look out for:

• Old pipes or cylinders — units older than about 10 years, especially if installed with copper piping or fittings, are at higher risk.
• Corrosion around valves or fittings — visible rust, greenish stains (common with copper corrosion), or flaking metal.
• Discoloured water or blue‑green staining on sinks, drains or baths — often a sign of metals leaching from corroding pipes.
• Pin‑hole leaks and small drips — tiny leaks are often the first sign of internal corrosion thinning pipe walls.
• Reduced efficiency or hot water heater failure — corrosion inside a hot water cylinder can compromise heating elements, insulation or tank integrity, leading to breakdowns.

If you notice any of these — especially in an older property or one connected to a chlorinated water supply — it’s worth investigating further before major damage occurs.

How to Protect Your Hot Water Cylinder & Plumbing from Chlorine Damage

The good news: there are practical steps homeowners can take to mitigate the risk of chlorine-related corrosion.

1. Use corrosion‑resistant cylinders or pipe materials — Where possible, choose cylinders and pipes made from materials less prone to chlorine-related damage. Options such as stainless steel or enamel-lined tanks are often recommended in chlorinated-water areas.
2. Regular maintenance and inspection — Have a qualified plumber check your cylinder and plumbing every few years (e.g. every 2–3 years) for early signs of corrosion, leaks, or degradation.
3. Watch out for hard water issues — If your water supply has high calcium or magnesium content, consider using water softeners or installing filters — but be aware: even softened water can react with chlorine, so speak with a qualified installer about the best approach.
4. Replace older systems proactively — For cylinders more than a decade old, especially those using copper and exposed to chlorinated supply, proactive replacement may save you from unexpected failures and water damage.
5. Choose a trusted installer for correct installation and galvanic protection — Poor installation or lack of galvanic isolation (e.g. mixing incompatible metals) can accelerate corrosion and decrease lifespan.

What Were the Trade‑offs and Challenges with Hunson RT

Even though the Hunson RT was advanced for its time, it came with compromises. Homeowners replacing an RT cylinder should be aware of these:

• Semi‑hybrid pressure behaviour: The RT was neither a traditional low‑pressure cylinder nor a full modern mains‑pressure cylinder. Its design delivered mains pressure to the shower via a heat exchanger — but taps, baths, and laundry stayed on low‑pressure supply. That meant inconsistency in water flow throughout the house.
• Incompatibility with modern plumbing standards and tapware: As modern homes shifted to mains‑pressure systems, tapware and mixers were designed for equal pressure. The RT’s hybrid pressure output made it harder to justify or retrofit modern tapware without risk of mismatched flow.
• Risk of inadequate output under demand: Since only one outlet would get mains pressure, running multiple outlets or high-demand appliances simultaneously often resulted in poor performance — an unacceptable limitation by today’s standards.
• Maintenance and reliability concerns: The complexity of the dual‑mode design (storage plus coil) increased maintenance demands; and over time, copper and weld seams age — making the system less dependable compared to modern welded‑steel, fully mains‑pressure cylinders.

In short: while the Hunson RT was a clever stop‑gap solution for a time, its compromises make it a poor fit for modern hot‑water expectations.

What to Consider When Replacing a Hunson RT Cylinder

If your home currently has a Hunson RT cylinder — or if you suspect it does — here are important considerations when replacing it:

• Upgrade to a full mains‑pressure cylinder: Modern mains‑pressure cylinders (welded steel, enamel‑lined or stainless steel) are the standard for new installations. They deliver equal, robust pressure to all outlets — showers, taps, appliances — and suit modern tapware and plumbing.
• Check cylinder size and household demand: Ensure the new cylinder capacity matches your household’s hot water usage (e.g. number of people, simultaneous showers, appliances). For typical Kiwi households, cylinders starting around 180 L are common; larger households may need more.
• Verify compliance with safety and water‑use regulations: Modern cylinders must have proper safety valves (e.g. temperature–pressure relief, cold‑water expansion valves if required), and meet current building code requirements.
• Upgrade tapware if needed: Because older tapware may not be designed for mains pressure, it’s usually best to upgrade taps, mixers, shower roses etc. when installing a new cylinder — to ensure correct flow and avoid leaks or damage.
• Budget for proper installation: Switching from a hybrid RT to a modern mains‑pressure cylinder often involves more than just swapping tanks — you may need new valves, waste‑pipes, updated plumbing, and adequate drainage.

What This Means for Cylinder Owners in Hastings (and Similar Areas)

If you live in Hastings (or an area with similar water chemistry), and you have an older copper low‑pressure hot water cylinder, there are several implications:

• Your cylinder is at high risk — especially if it’s been installed for many years. The rate of failures suggests that even relatively recent installations may be vulnerable.
• Warranty or manufacturer support may not apply — many manufacturers have explicitly excluded high‑risk areas from warranty coverage, meaning replacement or repair costs may come out of pocket.
• Corrosion may develop silently — “pitting corrosion” often starts inside the tank and may not be obvious from the outside until leaks or pin‑hole failures occur. Regular inspections are therefore especially important.
• Chlorination alone isn’t to blame — so simply switching off or changing disinfection methods may not solve the problem. Water chemistry (alkalinity, dissolved organics) must be considered.

What’s Been Proposed — Chemical Treatment or Replacement

The investigation recommended a chemical water‑treatment regime to stabilise the water chemistry — a method used in other countries to control corrosion in municipal water supplies.

• Chemical treatment approach: This would adjust the water’s chemistry (e.g. raise alkalinity or add protective agents) to make it less aggressive toward copper plumbing and cylinders. If properly implemented across the supply network, this could significantly reduce future cylinder failures.
• Non‑treatment / homeowner approach: Because implementing chemical treatment on the entire water network involves cost and coordination, many homeowners are being advised to replace copper LPCUs proactively — ideally with cylinders made from more resistant materials (e.g. enamel-lined steel or stainless steel) suited to aggressive water.