The raft of energy and building legislation driving the construction industry is causing clients and designer a real headache. For example, what is the difference between PassivHaus design standards and Code for Sustainable Homes (CSH) assessment design? – Typically a PassivHaus will acheive a code for sustainable homes rating of code lvel 3 or 4. This means that it is an ideal methodology for achieving the higher level of the overall code rating, whilst minimising the cost of renewables.
Q: What does PassiveHaus mean?
The term PassivHaus refers to a specific construction standard for buildings which have excellant comfort conditions in both winter and summer. These principles can be applied not only to the residential sector but also to commercial, industrial and public sector buildings. For houses, it is claimed that this is the world’s leading standard in energy efficient construction. They are designed and built using a ‘step-by-step’ approach with efficient components and a whole house ventilation system to achieve exceptionally low running costs to create something which is comfortable, healthy and sustainable.
Q: Is the Code for Sustainable Homes better than PassivHaus?
They both have different objectives – The Code targets a wider set of environmental standards while the other covers the energy requirement required for space heating. They are mutually beneficial.
Q: What are the challenges for a PassivHaus design?
By far is the requirement to achieve the required level of air-tightness, minimising the risk through good design and specification.
Q: Is it costly designing and building to a PassivHaus standard?
EU experience and case studies show an extra 6% i likely on the build cost. There are not yet enough UK houses to make a proper comparison, although the BRE is currently advising on a London project which has apparently been built for the same cost as a typical social housing unit.
Q: Are PassivHaus products widely available?
Yes. However, windows have at this present time to be imported thus increased price hike.
Q: Will adopting PassivHaus facilitate compliance with Building Regs and the Code for Sustainable Homes?
Yes. If a compliant design specification is derived from the PHPP (PassivHaus Planning Package) and transported into SAP, a 30-45% improvement in carbon emissions can be realised -without the use of heat-pump, biomass or other LZC/Renewable technology.
Q:What simple PassivHaus techniques are there to implement?
Insulation (typically 30cm thick)
Windows (airtight, triple glazed with thoroughly insulated frames achieving a U-value of 0.8 including the frame)
Airtight construction (max 0.6 airchanges/hr under 50 pascals pressure) with very efficient mechancial heat recovery ventilation.
Assuming that these three main performance targets are met, together with detailing to eliminate cold bridging and numerous other detailed requirements prescribed by the PHPP software, it is possible to eliminate the need for a boiler and the need for radiators or underfloor heating
