Why Greenwood
Why do the furnaces burn so clean
Greenwood Crossfire Combustion
Introducing the Frontier Series

Greenwood Heating NZ Ltd

6 High St
Timaru

Greenwood Gasification Wood Boilers

Innovative American technology produces amazing efficiencies

The Greenwood wood burning gasification boiler represents the latest innovation in sustainable wood burning boilers.  Imported from America and derived from 20 years of development, the Greenwood wood boiler is the most efficient, wood burning boiler you can buy for your home.

Recognized as the leader in renewable heating appliances, Greenwood's wood heating systems' patented designs improve combustion and thermal efficiency, which enables cleaner operation and delivers more energy to your home. That means less wood, fewer emissions and a warmer home for each dollar spent on fuel. Greenwood systems:
  • Can reduce heating bills by 70%
  • Operate virtually smoke and creosote free
  • Leave little ash, reducing frequency of cleaning
  • Consume 50% less wood than traditional outdoor wood furnaces

Why Greenwood

Greenwood Frontier Series hydronic furnaces can be integrated with most existing heating systems including, radiators, in-floor heating, and boiler systems and may be located in your basement, garage or shed. The boilers provide heat-on-demand, mitigating the need for a large storage tank. Controlled from the thermostat in your home, Greenwood solutions deliver the heat you expect at a fraction of the cost.
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Why do the Greenwood furnaces burn so clean?

To understand why the Greenwood wood boiler "burns clean," it is helpful to understand how wood burns. Here's the scientific explanation... when you kindle a fire, the temperature accelerates to around 260ºC  at which point the wood begins to breakdown chemically and throw off volatile gases. These gases catch fire and accelerate the temperature to about 590ºC, at which point the wood solids begin to burn. If the temperature remains at or above 590ºC, the fire consumes all of the wood gases and solid materials, and you have a "clean burning" fire. If not, you have incomplete combustion, which means unburned gases and particulates are vented by the furnace. Some of it escapes out the chimney as smoke; the rest cools down and remains in the chimney in the form of creosote.

Most wood burning furnaces and wood boilers on the market today are unable to sustain a temperature of 590ºC or higher. They are built with a firebox made of steel which is surrounded by a jacket of water. This water jacket serves two purposes: it transfers heat from the firebox to the home heating system, and it cools the steel firebox and keeps it from melting. The problem is, by keeping the firebox cool, the water jacket also cools the fire and prevents it from burning at temperatures needed for complete combustion. That's why these units produce irritating smoke and potentially dangerous creosote.


Greenwood's hydronic wood furnace is built in an entirely different way. Our firebox is made of super-duty ceramic refractory, cast four to six inches thick, and surrounded by outer layers of insulation designed to keep the heat in. The natural draft system pulls air into the furnace which fans the flames and creates a roaring fire with sustained temperatures of 980º to 1000ºC. Heat from the fire is captured by a water tube heat exchanger located above the firebox in the path of the escaping superheated gases. The furnace extracts heat from these escaping gases, not the fire below.

This innovative design enables the Greenwood wood boiler to burn cleanly and operate at a very high level of efficiency. By the time the escaping gases leave the furnace, they have cooled to around 300ºF. The 1700ºF difference in temperature between firebox and the vent represents the amount of energy captured to heat your home. The Greenwood hydronic furnace burns clean and delivers up to 85% of the wood's thermal energy to your home heating system.

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Greenwood Crossfire Combustion System

 1 UNDER-FIRE ZONE: Under-fire air from the pinhole grate drivers the rate of pyrolysis.
 2 COMBUSTION ZONE: 340 kg of refractory relect energy back into combustion chamber maintaining temperatures >760 degree C.
 3 CROSSFIRE ZONE: Over-fire air is added following the separation of gases from the wood pile.
 4 BURN-OUT ZONE: Combustion is completed in the burn-out zone where gas temperatures reach 1100 degree C.
 5 HEAT EXCHANGE ZONE: Heat is transferred to the water-tube heat exchanger in an isolated chamber. This is the only area where heat is transferred to water.
 6 EXHAUST ZONE: Exhaust gases leave the boiler at temperatures of 90-235 degree C depending on firing rate.
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Introducing the Greenwood® Frontier Series

Born through American innovation and manufacturing, the Frontier Series is Greenwood's most advanced line of high-efficiency wood gasification boilers.  The inaugural model, the Frontier CX, achieves EPA Phase 2 standards and provides homes up to 280 square metres with enough heat to heat their entire home and all hot water.

Built on feedback from owners of the award-winning Greenwood Furnace and Aspen Series boilers, the Frontier Series was designed with today's busy homeowner in mind. Breaking new ground in wood boiler performance, each Frontier Series comes with Greenwood's patented Crossfire Combustion System and an industry-first SmokeGuard system. The Greenwood® Boiler Management System provides intelligent control that continuously monitors and adjusts the boiler to ensure peak performance.
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Click here for page 2 on the Greenwood Frontier Series Boiler specifications Boiler specifications Boiler specifications