• Welcome to the Zero Carbon and Passivehouse
• Introduction: Global Warming, Passivehouses and Zero Carbon
  • 'Zero carbon'
• New Passivehouses
  • Passivehouse Principles
  • Scandinavian Homes Passivehouses
  • Large Passivehouses
    • Care Homes
• Building Renovation - IRULES™
  • IRULES™ - Incremental Renovation to Ultra-Low Energy Standard
• Passivehouse Heating and Ventilation
• Software
  • Meteonorm
• Energy Performance Certificates
  • What's an EPC?
  • How to get an EPC
• Get off the grid!
• Passivehouse Events
• Passivehouse Literature and Downloads
• Niels' Take On...
  • Niels' Take On Wind Turbines
• About Us
• Contact Us

New Passivehouses

From the perspective of building physics you can talk about two different philosophies representing the ends of a spectrum of possible building solutions. All modern buildings are of course ultra-insulated in order to create a pleasant interior climate including a comfortable temperature, keeping heat out when it is hot outside and keeping heat in when it is cold.

At one end of the spectrum you find houses which are airtight. These houses tend to incorporate advanced building technology and are, being airtight, by necessity mechanically ventilated. The ventilation system normally recovers around 80% of the heat from the air that is expelled from the building, and it can in some circumstances also be used for heating and/or cooling. The system is designed in such a way that it provides a suitable rate of air change to control humidity, smells and oxygen. To be able to perform this range of functions the technical system must be designed as part of the building design process in a holistic cooperation between architects and engineers, i.e. by companies staffed by a productive combination of creative and technical people. Zero-Carbon Solutions is one such company. The state of the art of this type of building is the passivehouse as defined by Dr. Wolfgang Feist of the PassivHaus Institut in Darmstadt in Germany.

At the opposite end of the spectrum we find buildings that can 'breathe', i.e. they are constructed from permeable fabric. Thus, at least theoretically, they do not require mechanical ventilation. Excess humidity, etc, can escape by diffusion through the walls as described by Fick's law. Some people consider this type of buildings to be more 'natural', and like passivehouses, they can be build to use extremely little energy and to have a very small ecological footprint. An excellent example of this type of building is the bio-solar house invented by the German engineer Klaus Becher. You can find further information here.

Construction methods

Houses adhering to either of these philosophies (and almost everything in between) can be made using several different construction methods, e.g. masonry, timber frame or even straw bales. The choice of construction method depends on many factors, including to an extent the location of the building, planning considerations, personal preferences, costs and the availability of local materials.

Most types of houses can accommodate some degree of participation or self-build. This is particularly true for relatively low-tech houses like bio-solar houses, while reaching passivehouse standard requires a very high degree of craftmanship. Passivehouses are not normally suitable for self-builders - they are simply too difficult to get right when constructed on site.

For this reason we prefer to manufacture passivehouses in factories with tight quality control, using timber frame technology. The build quality attainable using this method is almost always higher than using any other method because the materials are kept dry throughout the process, the production quality is uniform and correct because e.g. fasteners are applied by computer controlled robots - none are missing, they are all inserted at the correct angle and to the right depth. All insulation materials are dry and present. Once all the parts have been manufactured they are delivered to the build site on trailers or in containers and erected by specialist building workers that do nothing else. This is the easiest (albeit not the only) way to ensure passivehouse quality. Of course timber frame buildings can have an outer cladding made from stone or masonry.

The British government's 'zero carbon' concept is not a technical concept but a fiscal/political concept. Hence a 'zero carbon' building is not defined through a set of technical design rules. As a consequence a passivehouse is not necessarily a 'zero carbon' house. However, it is difficult to conceive of a 'zero carbon' house that is not close to the passivhouse standard in terms of energy consumption. The 'zero carbon' concept, however, also takes into consideration how the energy used is generated and in doing so, promotes ecological energy generation. Zero-Carbon Solutions can design buildings, including their energy supply, or indeed whole developments, to 'zero carbon' rules.