A rigorous, voluntary standard for energy efficiency in a building, Passivhaus accreditation is the forefront of reducing the ecological footprint of a building, with ultra-low energy consumption resulting in a reduction in the use of energy for heating or cooling, thus, being the foremost tool in tackling and removing fuel poverty.
The Passivhaus Planning Package (PHPP) is the energy modelling tool used to determine whether a building can achieve the required standards. PHPP is also used as an interactive design tool to refine the project design and construction detailing.
Any variation in specification of materials, services systems design and layout must be tested to check the energy standards are met, including any changes that occur on-site. From a design point of view, Passivhaus homes must adhere to:
1. Optimising the building shape and orientation to reduce heat loss and maximise solar gain
2. Super insulating the building fabric
3. Reducing ventilation heat loss with an airtight fabric
4. Providing continuous fresh air with mechanical ventilation and heat recovery
5. Reducing primary energy demand to less than 120kWh/m²/year and applying renewable energy systems when appropriate
Fort the Dormont Park development, all of the homes are delivered to an enhanced standard as a result of CCG’s offsite manufacturing capabilities and the use of the ‘iQ’ Timber System with a bespoke wall solution achieving a U-value of 0.095W/m²K. To ensure continuous, healthy air throughout each property, this airtightness was matched with the use of an MHVR System, a system that delivers a heat recovery rate of 90%.
The domestic hot water for the houses is provided by solar thermal panels feeding a storage tank that is supplemented by a log burning stove with a back boiler. The selected unit takes 90% of the heat to the hot water tank and has a direct combustion air feed from outside. CO2 emissions from this unit are 4g/kWh in comparison with 304 g/kWh for heating oil.
Overall, residents at Dormont Park can expect bills for heating, lighting and hot water to be as low as £150 per year with total energy costs for a 3-bedroom property reaching just £700.
Green Apple Award for Environmental Best Practice 2012