- Air tightness
- Choice of Fuel
- Combined Heat & Power
- Electric lights & appliances
- Embodied Energy
- Energy Harvesting
- Heat stores
- How Much Insulation?
- Insulation properties
- Passivhaus standard
- Thermal Mass
- Wall insulation
Energy use in our society is almost always associated with pollution and habitat destruction so all types of energy use are worth looking at:
- While a house is being built
- reducing embodied energythe total amount of energy it takes to make a material (or a building). See more on embodied energy of the building materials
- reducing associated ‘building site’ energy
- During its lifetime
- high levels of insulation
- good air tightnessA measure of how leaky a building is to air. In other words, how draughty it might be. There are now standard fan pressure tests to check how air tight a house is and the Building Regulations have minimum standards for all new houses (L1A – Conservation of fuel and power in new dwellings (England)). A much higher degree of air tightness is covered by the Passivhaus standard
- renewable fuels
- low energy lighting and appliances
- efficient means of heating including good controls
- low maintenance
- natural lighting
- Upon demolition
Where can the biggest savings be made?
Undoubtedly the main savings are to do with while the house is in use (rather than during construction) and are mainly related to heating and lighting. Particularly the heating and fixed lighting are important because, especially with the heating, it is very difficult to increase the insulation values of the structure after it has been built. It may last for hundreds of years in basically the same state that it was built originally. Items such as electrical appliances and movable lighting are important but tend to get changed every decade or two.
The embodied energy is often cited as being much less important than energy in use (sometimes mentioned as being very roughly a tenth) but that way of looking at it is based on the notion of traditionally very high levels of energy in use. Once you start to reduce the energy in use then the embodied energy starts to take on significance.
The energy associated with building sites has had very little study, especially for self build. It is probably mainly to do with transport costs, which can be relatively high, particularly in the countryside where delivery journeys for materials can be quite inefficient.
Upgrading existing property
This is a much bigger challenge than building from scratch but there are already a couple of examples in the UK of old houses being brought up to Passivhaus standard: Under the Sun in Birmingham and one in Lambeth, London. Work is more advanced on the continent, particularly in Germany.
The Retrofit for the Future database gives details of dozens of mainly housing association and council properties which are in the process of being brought up to high insulation and air tightness standards. The PDFs go into considerable detail about the methods
‘Fabric First’ Although waiting for an update (as of 21/10/2012 the guide is based on out of date Building Regs and SAPStandard Assessment Procedure - the method used in the building regulations for calculating the energy use of a house. see Part L and SAP), the ESTEnergy Savings Trust guide Fabric First contains a great deal of very useful information about the design of a building’s fabric.
The Green Deal. The government’s efforts to stimulate a variety of methods for greening a house, from solar collectors to insulation, are almost impossible to keep up with! They have been alternately ignored by the public or so oversubscribe that it was necessary to close them only days after they were announced. This has made it very difficult for the various industries to gear up properly over an uncertain time span. Some have been very sensible, particularly around insulation, especially external insulation. Check out the Green Deal flavour of the minute.
Nottingham Energy Partnership are a not for profit organisation who “devise, manage and deliver domestic and commercial projects that tackle fuel poverty, cut carbon emissions, and make businesses more sustainable”