LTD or ECO model? - Choosing the right wood fire

National Environmental standards came into effect throughout New Zealand on the 1st September 2005 placing more stringent emission & efficiency requirements on all wood fires installed on properties with a land area of less than two hectares. In practical terms this effectively creates two distinct wood fire markets and as a consequence Metro make two different models, ECO Metro’s and LTD Metro’s.

LTD models

LTD Metro’s comply with AS/NZS4013:1999 and although this is still the current Australian & New Zealand emission standard the National Environmental standard takes precedence if installations are on properties with a land area of less than two hectares. LTD Metro’s can therefore only be installed on a property with a land area of two hectares or greater.

A major feature of the LTD Metro’s is their responsive total control of burn rate with overnight burning capabilities. Independent testing carried out in a NATA registered laboratory recorded burn times and output which were set at a very low burn rate on a single fuel load of 100mm x 50mm pine blocks. The results were quite remarkable, with 35kWs of energy being released over 22 hours, an average output of 1.6kW’s per hour.

ECO & ECO DV models

ECO models have a design specification which differs to their LTD counterparts, with the emphasis on burning hot and clean. Metro’s ECO fireboxes utilise a secondary burn chamber and secondary air supply combination unique to Metro, which eliminates the ongoing and costly replacement of secondary air tubes used by most other brands.

Not only have all ECO models achieved Metro’s self imposed 1gm/kg in particulate emissions (National Environmental standard allows 50% higher emissions of 1.5gm/kg), but most ECO models have also achieved compliance with the national standard tested with a wetback fitted.

Metro have released some selected ECO Metro’s with DV (Direct Vent) options. This is the latest in combustion technology enabling all the Metro ECO DV’s combustion air to be pre-heated to very high temperatures before it enters the firebox, which allows for greater combustion temperatures, lower emissions and higher efficiencies.

These ECO DV models also allow you the option of connecting the combustion air supply to outside the home, further improving the heating efficiency within your home.