There is a huge range of energy sources you can use to power your central heating including diesel boilers, gas boilers and solid fuel fired boilers.
Diesel Fired Boilers
Modern diesel boilers have really developed into something special. Far from being the big, dirty and noisy machines we expect, modern diesel boilers are incredibly small, quiet and powerful, and easily meet New Zealand's stringent emission laws.
Typical boilers are roughly the size of a modern washing machine and due to their small size and quiet operation they can be easily 
stored in the garage, laundry or even a cupboard.
How do diesel boilers work?
Diesel boilers warm your home by heating water which is piped around the home into heating radiators, under floor heating, hot water cylinders, spas and even swimming pools. Heating your home like this is extremely efficient - the action of pumping water is much more efficient than pumping air!
Homes with a diesel boiler will require a fuel tank to be installed outside the home, however these are usually easy on the eye and smaller than you would expect so they will not have an impact on the appearance of your garden or outdoor areas (see right).
Gas Fired Boilers
Thanks to the cheap and easily available natural gas and LPG in the North Island Gas Boilers are an extremely cost effective heating and hot water heat source.
Modern gas fired boilers are compact, quiet and unobtrusive which makes them perfect for domestic radiator and hot water heating situations. Gas boilers have the lowest install cost of any heat source and many are small enough to fit in a kitchen cupboard.
Gas fired boilers are famous for providing almost unlimited hot-water. No matter how many people you have needing a shower in the morning, no-one will end up having to put up with a bone-shatteringly cold shower. Gas fired boilers effectively heat the water in your hot water cylinder as fast as you can drain it!
Gas boilers can be positioned almost anywhere in your home and are designed to ensure that oxygen is not depleted in the house by the burner and that condensation is not created.
Solid Fuel Fired Boilers
The fluctuating prices for fossil fuels has meant that solid fuels such as wood are becoming an increasingly viable fuel, particularly for rural or lifestyle blocks where wood is easy and cheap to get hold of.
The most common solid fuel boiler option is a wood fired log boiler. While a wood fired boiler sounds a little bit simple and old fashioned, modern variations of these boilers produce a surprising amount of heat without needing to be continually stoked to maintain this heat.
How do solid fuel boilers work?
The boiler is filled with logs or pellets which is then set alight. Once the boiler is up to the required temperature it heats the house as per a normal boiler and can be topped up with more wood if required or left to burn out.
Many modern boilers can regulate the temperature of the boiler and heating system by controlling the fan and the air damper so that it is effectively like adjusting the heat on a gas or diesel boiler.
To achieve the best results it is highly recommended that these solid fuel appliances are connected to a thermal store cylinder. These cylinders store and control the heat produced, reducing the required stoking time for convenience. A thermal store cylinder will also increase the lifetime performance of the boiler saving you maintenance and replacement costs as well as a few cold nights!
How you can get the most out of your wood
Another form of solid fuel boiler is the Gasification Boiler. These boilers are more advanced and efficient than other boilers because they superheat the ash and smoke from the burnt fuel which then combusts to a point where there is very little left. This means that rather than just burning the ‘easy’ fuel, these boilers burn EVERYTHING so that you don’t need to stoke and reload the boiler as often.
What is a Pellet Fired Boiler?
A pellet fired boiler works in exactly the same way as a wood fired boiler with the only difference being that wood pellets are used instead of your more traditional logs of wood.
Wood pellets are very similar to what they sound like – small cylindrical pieces of wood roughly the size of a little finger nail. They are almost always made out of wood shavings and sawdust and have a number of advantages over traditional firewood:
-
They are more compact so you can store more wood at a time
-
They burn extremely efficiently,
-
They are 98% combustible and leave very little ash behind so you have to clean up less.
-
They are also extremely easy to handle, usually coming in 20kg sacks, and can be used in all wood fired boilers.
