If you're considering a new hot water cylinder, one of the first decisions you'll need to make is whether to go with low pressure or mains pressure. It’s a big choice - and the right one depends on your home’s plumbing, your budget, and how you want your water to perform.
At The Hot Water Doctor, we’ve helped Auckland homeowners make this decision for years. Whether you're upgrading your old system or starting fresh, here’s what you need to know about the difference between low and mains pressure hot water cylinders.
💧 What Is a Low Pressure Hot Water Cylinder?
Low pressure cylinders are typically found in older homes and are designed to operate at a much lower pressure—usually no more than 76kPa. This pressure is regulated either by a pressure-reducing valve installed before the cylinder or by a header tank located in the ceiling. As a result, hot water is delivered at a significantly lower pressure to all tap outlets, which can make these systems incompatible with modern tapware and high-performance showers. You’ll never find low pressure cylinders in new homes, which are built with more efficient and powerful mains pressure systems as standard.
Pros:
More affordable upfront
Ideal for older plumbing setups
Less strain on aging pipes and tapware
Cons:
Weaker water pressure, especially with multiple outlets running.
More potential for faults due to imbalanced hot and cold water pressure.
Not compatible with many modern tapware options
Slower water delivery
🚿 What Is a Mains Pressure Hot Water Cylinder?
Mains pressure cylinders are designed to handle significantly higher pressure than low pressure systems. This allows them to be connected directly to your home's cold water mains supply, delivering stronger, more consistent water pressure throughout the house. In rural settings, they can also be installed with systems fed by a rainwater tank and pump. With a mains pressure hot water system, your hot water flows at the same—or similar—strong pressure as your cold water, providing a balanced and more enjoyable experience at every tap and shower.
Pros:
Powerful, even pressure across all taps and showers
Works with modern tap mixers and high-pressure shower heads
Faster delivery of hot water
Great for busy households
Cons:
Higher installation cost
May require tapware upgrades in older homes although not usually.
🏠 Which System Is Right for You?
Your Situation | Recommended Option | |
|---|---|---|
Building or renovating | Mains Pressure | |
Want stronger water flow | Mains Pressure | |
Older home with original plumbing | Low Pressure or Upgrade to Mains Pressure | |
Looking for lower upfront cost | Low Pressure | |
Tired of weak showers or pressure drops | Mains Pressure | |
🔧 Thinking of Upgrading? We Make It Easy
We specialise in upgrading low pressure systems to mains pressure and complete the switch in just one day.
And with Dean’s Limited Electrical Licence, we can safely handle both the plumbing and the electrical side of the job - no need to bring in a separate electrician.
📸 Get a Fixed Quote Without a Site Visit
We make quoting simple. Just take a few clear photos of your current cylinder and the surrounding pipework, and send them to us via our quote form or email. We’ll send back a no-obligation fixed-price quote - fast.
✅ Why Choose The Hot Water Doctor?
Over 260 five-star Google reviews
30+ years of experience
Master Plumber Certified
Trusted Auckland-wide
No shortcuts - just honest advice and quality work
📞 Let’s Get Started
Need help deciding what’s best for your home? Give Dean a call on 0508 HOT DOC or send us a quote request.
