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The term Passivhaus refers to a rigorous, voluntary, standard for energy efficiency in a building (domestic, commercial and public) which significantly reduces its ecological footprint. It results in ultra-low energy buildings that require little energy for space heating or cooling. It is a design process that is integrated with architectural design and can be applied to refurbishments as well as new builds.
Passivhaus is the fastest growing energy performance standard in the world with 30,000 buildings realised to date, the majority of those since 2000. The Passivhaus Standard’s strengths lie in the simplicityof its approach – build a house that has an excellent thermal performance and exceptional airtightnesswith mechanical ventilation!
This robust approach to building design allows the designer to minimise the ‘Heating Demand’ of the building and in some residential buildings only specify a heated towel rail as means of conventional heating, this heat can then be recovered and circulated by a Mechanical Ventilation and Heat Recovery (MVHR) unit.
As well as being an energy performance standard Passivhaus also provides excellent indoor air quality, this is achieved by reducing the air infiltration rates and supplying fresh air which is filtered and post heated by the MVHR unit.
The Passivhaus Standard can be applied to any climate in the world and works equally as well in warm climates as it does in more moderate climates. To date Passivhaus buildings have been designed and built in every European country, Australia, China, Japan, Canada the USA and South America.-.a research station has even been constructed to the Passivhaus Standard in Antarctica
As we become more aware of fuel poverty it becomes increasingly important to reduce our dependence on fossil fuels, with fuel prices continuing to rise, the low heating demand of Passivhaus Buildings of less than 15kWh per square metre per year means that annual fuel costs are reduced by a factor of 5-10. For example a household living in a 70m2 Passivhaus with gas heating could spend as little as £25 on space heating each year.
It has been proven that a Passivhaus will not fall below 16°C, even without heating during the coldest winter months; this is due to the excellent thermal performance and low air infiltration rates.
So where does Passivhaus sit in relation to the Code for Sustainable homes and BREEAM? The distinction is quite simple: Passivhaus is a specific energy performance standard that delivers very high levels of energy efficiency, whilst the Code and BREEAM are overarching sustainability assessment ratings which address a large number of environmental issues.
These standards are by no means mutually exclusive. Passivhaus has already proved itself on several UK projects to be cost effective whilst delivering a ‘fabric first’ approach for an energy efficient means of delivering higher levels of the Code and BREEAM.
Of all of the Code and BREEAM categories the sub section which accounts for Energy and Carbon Dioxide emissions is one of the most heavily weighted and most difficult to achieve. In the case of the Code a percentage improvement is required in the carbon dioxide emissions of the dwelling for each successive level of the Code. For dwellings these carbon savings are defined according to the Standard Assessment Procedure (SAP) as required by Part L1 of the UK Building regulations.
In non-domestic buildings the situation is very similar whereby the BREEAM standards award Energy credits by comparing the building’s CO2 index (or EPC Rating), taken from the Energy Performance Certificate (EPC), with a table of benchmarks. A National Calculation Methodology (NCM) is used to calculate the Building Emission Rate in accordance with PartL2 of the UK Building regulations and this becomes the basis for EPC rating and BREEAM Energy credits.
By adopting the Passivhaus ‘fabric first’ approach the level of renewable energy interventions needed to deliver higher levels of the Code or BREEAM targets is greatly reduced. Any renewable energy produced onsite by a Passivhaus will typically achieve a greater profit margin since a higher component will be fed-back to the grid as a result of the standard’s stringent primary energy target.
The Passivhaus standard for central Europe requires that the building fulfills the following requirements:
The PassivHaus standard focuses on the following elements:
At CEADA we have PassivHaus experts, with particular expertise in the refurbishment of Social Housing sector.