Woodfire Passiv Ecodesign Wood Burning Boiler Stove

It's fair to say that the Woodfire Passiv has moved boiler stoves on leaps and bounds and well beyond the point where everyone thought that Ecodesign, with its exceptionally low emissions standards, would write them off. Old style wrap-around multi fuel boiler stoves, that by their very nature reduce flue gas temperatures and therefore create more emissions, were never going to get close to the exacting 2022 Ecodesign requirements and consequently everyone has phased them out. What Woodfire have done with their Passiv wood fired central heating boiler is to completely re-think the way that boiler stoves work and in doing so they have produced an exceptional, virtually carbon neutral, highly efficient and emissions-friendly, domestic heating appliance fired by wood logs that's certainly worthy of a place heating even the greenest of homes. It's easy to see why they named it the Passiv.

A boiler stove that produced an efficiency of 85.8% would have been unthinkable a few years back. It's even hard to believe now, especially when you consider that many of the best non-boiler Ecodesign stoves struggle to make it to mid-80s efficiency while at the same time producing the low emissions required to pass Ecodesign. The Woodfire Passiv excels at both and can still deliver a practical balance of easy-to-live-with heat to the room (3kW) as well as a generous supply of domestic hot water and heat to the radiators (7kW).

It does this by placing its water tank, which incorporates a grid of Swiss cheese-like heat exchanger tubes, above the fire chamber where most of the heat is generated. This allows the maximum heat to pass through these passageways and thus warm the water. Although the tank isn't as big as in a traditional boiler more of its surface area is in contact with the heat making the Passiv much quicker at heating up the system and much more effective at keeping the flue gases warmer so that emissions are kept to a minimum. The firebox is completely insulated with vermiculite panels which adds to the Passiv's outstanding efficiency. Weighing in at some 195kg (30st 9lb) the Passiv is no lightweight either and shows you just how well it's constructed with no skimping on either materials or the quality of steel plate.

The Woodfire Passiv has two push-pull air controls (primary and secondary / tertiary), plus a clever push-pull flue damper set within the baffle plate to regulate potential strong updraught or adverse weather conditions. Between them these three controls ensure that you have total control over the burn rate, heat output and fuel efficiency. It also has a 100mm diameter direct external air supply inlet to make the stove virtually room-sealed and therefore suitable for use in rooms with extractors (eg kichen / diners) and low energy homes with mechanical ventilation heat recovery systems (MVHR). In addition the Passiv can be connected to either pressurised or open-vented systems to provide you with complete installation flexibility when combining it with other technologies.

Specifications

Drawing

Downloads

Woodfire Passiv Instruction Manual

Woodfire Brochure