Califont gas hot water heaters have increased in popularity in recent years, thanks to their top-selling point: instant hot water. 

Here are some things you should know about this type of hot water heater to see if it’s suited to your house. 

What is a califont?

A califont is a tank-less on demand gas-powered hot water system. These systems go by many names:

Califonts heater water on demand and only provides hot water when needed. There is no tank, or energy lost waiting to use hot water. These systems burn gas to heat cold water instantly. In New Zealand, these systems either use bottled LPG or natural gas from the mains line to your house. Typically califonts only use one type of gas, so make sure you use the right one. 

How does a califont work? 

The califont is switched on when you open the hot water tap. This is detected by the unit and cold water is run through the califont, a gas burner heats up the water in the heat exchanger and the hot water is piped to the hot water outlet.

The unit has an ECU (Electronic Control Unit) that controls how the gas flows through the hot water heater, the temperature controls, ignition, and modulation.

This is a very simple and effective system that allows you to have multiple hot water outlets open at the same time.

Flow rate

These units can heat between 16 and 32 litres of hot water per minute and that is referred to as the flow rate. This is determined by the size and heat output of the unit. Each household may require a different flow rate depending on their hot water requirements. Here are some questions you need to ask yourself when trying to determine your flow rate:

  • How many bathrooms do you have?
  • Where are the bathrooms and other hot water outlets in the building?
  • How often will your hot water outlets run simultaneously?
  • What type of tapware is installed?
  • Location within New Zealand

Califont in New Zealand

There are many califont manufacturers in New Zealand, but two really stand out from the rest Rheem and Rinnai

Rheem Instantaneous Water Heater

Rheem is a very reputable manufacturer and produces many models that suit homes in New Zealand. Most of their califont gas water heaters have the following features:

  • Flamesafe overheat protection
  • 6-star energy rating
  • Digital display for easy fault diagnosis and service
  • Frost protection down to -20
  • The units can link via Reem EZ Link, this links two units together for increased delivery
  • Optional remote temperature controllers

The range of Rheem califonts has a flow rate of 16L-27L per minute and their range suits a wide variety of households size-wise.

Rinnai Instantaneous Water Heater

Rinnai is the other reputable manufacturer that is very popular in New Zealand. They were the first manufacturer in New Zealand to introduce this type of water heating system, and have spent the years since then refining the technology for systems to make them efficient and cost-effective. Their Infinity range features califonts for both domestic and commercial purposes. Some of their units are condensing gas continuous flow systems which have a second heat exchanger that uses the waste heat from the flue gas to heat the water as well. This heats the water using less energy. Their models come in a range of flow sizes to suit all households. 


  • The units are relatively lightweight
  • They take up a lot less space than any other systems on the market
  • As long as you have gas, you won’t run out of hot water
  • These are relatively inexpensive due to a saturated market, with many second-hand  options as well
  • This hot water heating option works very well in small homes and may be more efficient than other options
  • The system does not use a tank, which means there is no buildup of harmful deposits
  • The unit is wall-mounted and can be installed outside and out of sigh
  • If the unit is installed and maintained correctly, it has an average lifespan of about 20 years
  • The units are very safe as they only operate when hot water is needed


  • This type of hot water heater produces greenhouse gases, however, this way of heating your hot water may be cleaner than electricity generated using fossil fuels
  • They can break down quicker if the unit is used to heat heard water, using a water softener will alleviate this issue
  • If your unit uses LPG gas cylinders, the gas cylinder will need to be replaced regularly and safety checks 
  • The units make a bit of noise when they operate, this needs to be considered before you decide where to install the unit
  • A qualified gas fitter will need to inspect and sign off on the installation, this adds time and money into the equation
  • The up-front cost of these units can be higher the unit may also need additional venting, which can be expensive 

If this sounds like something you’d like to install in your home, give us a call on 0508786424 or contact us online. Based on your budget and hot water requirements we can make some recommendations on which gas hot water heater would suit you best.