Passive House & Heritage Conservation
Over the past few years, Dieppe Design and Glenstone have worked on a number of heritage conservation projects incorporating Passive House principles. Using these principles we are able to provide our clients with more efficient and comfortable homes.
Passive House is a scientifically proven method of designing healthy, sustainable and economic buildings. It relies on five key principles,
Airtightness
Adequate ventilation strategy
Thermal insulation
Thermal bridge reduced design
Passive house windows and doors.
As a Passive House is built to an "airtight" standard of construction with a maximum of 0.6 ac/h (air exchanges per hour) it allows greater control of the indoor conditions. This requires that every surface is wrapped and taped with weathertight and airtight membranes. Particular care and attention is given to joints, windows and doors installations, using a series of flexible tapes and sealants.
When airtight construction is introduced, mechanical ventilation is required to provide sufficient fresh air to the building. Bear in mind the average Australian house has 15ac/hr, as air travels freely around unsealed construction joints, windows and doors. Therefore a heat recovery ventilation system (HRV) is used to provide a continuous supply of fresh and filtered air around the home. The HRV assists in controlling the indoor air quality and maintaining thermal comfort. Filters remove potentially harmful substances from the air. Due to Sydney's humid weather conditions, it is often coupled with an inline dehumidifier to control the moisture content in the air supplied to the home.
Every external surface of the building is insulated creating a complete thermal envelope. Particular attention is given to junctions to reduce thermal bridging to remove the risk of mould forming. When working with heritage buildings it is not always possible to create this complete envelope to the Passive House standard. For such areas there can be EnerPHit exemptions.
High performance Passive House windows and doors are required for certification. For Sydney's climate double glazing with LowE coatings offer us a good balance of thermal performance with cost and have become a minimum standard for our projects.
The test for all of the above results in a dwelling that ensures energy efficiency. By completing the Passive House Planning Package we are able to calculate the energy demand for the building. The maximum energy usage for a Passive House is defined by a Heating Demand of 15kWh/m2a and Cooling Demand of 15kWh/m2a. We utilise low energy use fixtures, fittings, and equipment including electric heat pumps for heating and cooling. Combined with renewable energy generated by photovoltaics it is possible to ensure that the homes energy demand is minimised, reducing energy bills.
These extra steps taken are not only best practice but act as quality assurance, meaning our clients can rest assured their homes are built to the highest standard.
Blog by Architect & Passive Home Design Specialist
Dieppe Design
