Wood Burner Flu Systems - Standard vs Eco or Heat Saver

Installing a new woodburner? You can improve the efficiency of your burner by using a heat saver flue.

All flues require a cooling air flow around the flue casings to ensure they do not set fire to the building. The way the flue is cooled can have a dramatic effect on the efficiency of your woodburner.  There are two types of flue to consider:


woodburner systems stnadard flu

The majority of flue systems draw the cooling air from inside the living room. This results in large volumes of warm air from the room being drawn up between the flue skins and expelled to the outside.

Laboratory testing has shown that up to 450 litres of heated air a minute is drawn out of the home. On a cold winter’s night this hugely inefficient system can empty a whole room full of hot air every hour. This lost air is replaced with cold outside air drawn into the house through gaps and cracks.

These flues will be losing air 24 hours a day, so even when the fire is not going, air will be lost from the room to the outside.


There are a number of manufacturers of these types of flues, the cost difference between a conventional flue and Eco/Heat Saver flue is often minimal, yet the performance gain is huge.

An “Eco/Heat Saver” type flue system draws the cooling air from either the roof space cavity or from outside the house, instead of from inside the home as a conventional flue system does.

woodburner systems eco heatsaver flu

These “Eco/Heat Saver” type flues ensure heat produced by the wood fire remains in the room, vastly reducing heat loss from your home.

An added bonus is that you will use much less wood and still have a toasty warm home. Less wood for more heat also equates to less harmful pollution into the air outside your home.

Ask your wood burner supplier/installer about Eco/Heat Saver flues.


Nelson City Council Environmental Programmes Advisor Richard Popenhagen
Phone 03 546 0251
Email richard.popenhagen@ncc.govt.nz