10 June 2017

Gas Water Heaters (Califonts) Explained

We've installed a gas water heater califont into our tiny house. There are multiple options in terms of water heating systems available but we chose to go down this route and below we explain why. (Watch the video for the 'how to' install.)

What is a califont? 

First up they are known by a number of names:
  • Califont
  • Gas water heater 
  • Water heater
  • Instantaneous water heater
  • Califont gas heater
  • Can be known by brand names like infinity
Typical domestic califont
A califont is basically a tank-less on demand gas powered water heater.  

Califonts provide hot water only as its needed. There is no tank or energy lost waiting to use the stored hot water. They burn gas to heat cold water instantaneously. In NZ they typically use bottled LPG or natural gas from the mains line to your house. In NZ califonts only burn one type of gas so ensure you use the right type.

Advantages of a califont:

  • Relatively light weight.
  • Small space envelope.
  • You won't run out of hot water (as long us there is gas).
  • Relatively inexpensive due to saturated market, including second hand options.
  • A lot of the install can be done by owner with consultation and sign off from a qualified gas fitter.
  • If you are running a solar system a califont works well due to using gas energy instead of electric. 
  • May be more efficient for small homes than other forms of heaters. 
  • No tank means less chance of harmful disposals building up.
  • Can be installed out of sight on the outside or inside of the house (depends on type of unit)
  • Life could be up to 20 years if installed and maintained correctly. 
  • Safe as they only operate when they heat water. 

Disadvantages of a califont

  • Produces greenhouse gas emissions, but may be cleaner than electricity generated using fossil fuels.
  • They can break down quickly if using hard water (use water softener). 
  • Gas bottles need to be filled or replaced regularly and require regular paid safety checks.
  • They produce noise while operating, consider this before selecting install location.
  • Qualified gas fitter needs to sign off install - added cost and time.
  • Can be a high up front cost - depends how this is tackled (can be both advantage and disadvantage as demonstrated on both these lists). 
  • May need expensive venting which can be unattractive.

Flow Rate

Flow rates vary from around 5 litres per minute to about 30L/min with the marine style at the lower end of the range. For two people in a tiny house 10-20L/min should be fine, we settled on 16L/min. So for example say the shower draws 10L/min there is still 6L/min to provide hot water at the kitchen sink. 

NZ standards

The relative NZ standard that needs to be followed is 'ASNZS 5601.2 LP Gas installations in caravans and boats for non-propulsive purposes'. This is a relatively light read and contains excellent information to keep everyone safe. We used the guys at Hagen and Owen to help us install.


We are using solar power to take our tiny house off grid so we needed to reduce our electricity draw where possible. Using a califont to take care of one of the big energy uses was essential for the off grid system.

Marine Califonts

We've gone for a domestic califont as our choice which is explained in more depth in the video above. However there are also Marine califonts which can be another good option for small spaces.

Typical Marine Califont

  • Primarily designed for boats but can work well for tiny homes. 
  • Tend to be cheaper than domestic.
  • Have more adjustment of gas and water flow. 
  • Tend to have lower flow rate.
  • Need a flue to extract combustive gas.
  • Lighter than domestic.
  • Batteries usually used to ignite flame. 

As always we would recommend giving it to go to install a califont yourself with help where needed. Please comment below if you have any questions. 

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