A mains pressure hot water system connects directly to your home's water supply at full mains pressure. This delivers strong, consistent hot water flow at all outlets — unlike low-pressure systems fed from a header tank. Mains pressure is the standard for all new NZ homes built from the 1990s onwards.
Low-pressure (LP) systems are gravity-fed from a header tank installed above the cylinder, typically in the ceiling or roof space. This creates low, inconsistent pressure at the tap. Mains pressure systems bypass the header tank entirely, using your home's direct water supply pressure — the same pressure you experience at the cold tap.
Yes — a mains pressure cylinder typically costs $800–$1,400 more than a low-pressure equivalent. When upgrading, you'll also need to remove the old header tank and cap the pipes, adding $200–$500 to the job. Total upgrade premium: $1,000–$1,900. Most plumbers and homeowners consider this well worth it.