Passive House Construction
A warm comfortable home with a healthy living environment, a home that is very low maintenance and a home that generates minimal running costs are among the many benefits to building – and living in – a Passive House.
Many factors are considered when creating these eco-friendly homes of the future – from orientation and shading to insulation, materials used, ventilation, and airtightness. The entire process is based on science: no guesswork involved!
Passive House Standard
ORIENTATION & SHADING
While Passive House projects are not dependent on solar gains to achieve thermal comfort and energy efficiency, they still benefit from careful consideration of the impact of sun paths and shading. The aim is to ensure that any solar gains will make a positive contribution towards meeting Passive House targets without the risk of overheating.
FORM FACTOR
The complexity of a building’s thermal envelope can have a significant effect on the insulation levels required to meet the Passive House standard. Firstly, a larger thermal envelope will transmit more heat per usable area, and secondly, a complex shape will involve more junctions that create difficulty and cost. Keep it simple!
INSULATION & THERMAL BRIDGES
In a Passive House, all components of the building envelope must be well-insulated. Insulation comes in numerous forms, from batts to straw bales, from SIP panels to vacuum panels, and the choice of the material and its thickness depend on the local climate. In addition, all edges, corners, connections and penetrations must be planned with special attention in order to avoid thermal bridges.
WINDOWS & DOORS
High-performance windows and doors are arguably the single most important component to get right in any Passive House project. Passive House certified windows are available in a number of different frame materials that satisfy strict criteria on thermal performance and airtightness.
AIRTIGHTNESS
Airtightness is central to attaining Passive House certification, but, most importantly, it is a key indicator of construction quality. Remember: a leaky building is not necessarily a breathable building and an airtight building is not automatically bad at managing moisture. Designers need to understand the interaction and independence of these mechanisms when planning, in order to have an airtight building with a healthy indoor environment and a robust, ‘breathable’ thermal envelope.
VENTILATION
While a well¬-designed thermal envelope is key for achieving thermal comfort, getting the ventilation right is similarly important for feeling cosy and fresh inside. Mechanical ventilation is not mandated by the Passive House standard, but it is the easiest way to meet the energy goals in hot and cool climates, and a precondition for reliable indoor air quality in all climates.
HOTWATER & HEATING
Heating systems in Passive House projects are generally a lot smaller than people expect! There are many different options available: small heat pumps, direct electric or conventional boilers. Oversizing the heating system can be a waste of money and efficiency. You need very little heat in a Passive House, so keep the heating system small, efficient, responsive and simple!
