"A Passive House is a building, for which thermal comfort (ISO 7730) can be achieved solely by post-heating or post-cooling of the fresh air mass which is required to achieve sufficient indoor air quality conditions – without the need for additional recirculation of air." Dr. Wolfgang Feist

The Passivhaus institute of Germany has laid out some criteria for energy efficient construction by which a building should be built, in order to qualify as a Passive house. This is administered through the Passive House academy of Ireland and the Certified Passive house Designers.

Unlike “Zero Carbon” the Passive House 

principals are only concerned with the energy performance of the building, no concern is 

given to the CO2 output of the building.

In contrast the Passive House principals are more energy efficient and stringent 

than those of Zero Carbon construction.

In short a 2000 sq ft house will cost less than £190 per year for space heating using a standard oil boiler and maintaining at a constant temperature of 20 degrees internally day and night all year round with excellent air quality and indoor comfort.

This may sound difficult to believe, but it does work and this is what can be achieved when the correct building principals are applied.

There are now 2383 certified Passive house designers spread across the world and Manus Mullan of Mullan Chartered Architects is one of the few Certified Passive House designers in Northern Ireland.

• Space head demand of ≤ 15kw/m2 per annum 
• Building heating load of ≤ 10w/m2
• Useful cooling demand of ≤ 15kwh/m2 per annum
• Primary energy demand of ≤ 120kwh/m2 per annum
• Building air tightness of ≤ 0.6 /h
• Excess temperature frequency ≤ 10%
• Windows U value of 0.85w/m2k “fitted”
• Window g value of 50 – 55 %
• Ventilation system efficiency ≥ 75%
• Thermal bridge free design details
• Some basic principals are applied in order to aid the achieving of the criteria
• Living quarters and larger windows to the south
• Service rooms and smaller windows to the north
• Keep the design compact
• Centralize the services