Sustainable Design
As holders of the ISO 14001 standard, our environmental impact and approach is at the heart of LPA, where long before the design process is commenced ensuring that the way the office is run, the reduction of waste, the use of environmentally friendly products and suppliers ensures that not only does the office have the smallest carbon footprint possible, but that it continues to monitor and improve the environmental performance of the operation.
After industry and transport, the biggest generator of CO2 emissions in the environment are buildings of which housing is the biggest generator. LPA therefore see the reduction of CO2 emissions as a key part of any design brief, whether as part of a small residential extension or to large scale new build and refurbishment projects. LPA will work with their client to advise of the most appropriate environmental solution for their particular scheme, able to to advise in terms of both design and cost. Where necessary LPA will draw upon expert consultants who they have long standing relationships with to provide in depth detailed analysis of the latest technology and lifetime analysis.
The environmental strategy for each scheme will vary from project to project, depending on factors such as design, lifespan, current legislation, cost and of course client requirements. The following criteria are some but not all of the important issues that are considered for each scheme.
1. The Building Envelope
The production of energy through photovoltaics or solar receivers immediately springs to mind when one is considering the environmental performance of a building, but actually long before considering energy production, the conservation of energy must first be considered to ensure minimum consumption. One of the biggest losses of energy in a building is through the building envelope; the floors, walls, doors windows and roof, where energy literally leaks out of poorly insulated roofs and badly fitted windows and doors. Ensuring air tightness of construction is therefore vital. Whether working on the refurbishment of an existing building or ensuring the correct detailing for a new build, ensuring that as much energy as possible is conserved will ensure that the least energy is inputted.
2. Insulation
In ensuring air tightness, insulation plays a key factor. Buildings can be insulated during their construction or retrospectively with products such as insulated plasterboard/cladding. Starting with the roof all components of the envelope are considered to include walls, floors and window insulation. The insulation of windows (one of the biggest factors in the loss of energy through a building) is considered through anything from high performance triple glazing to slimline double glazing suitable for the improvement of delicate sash windows found in Listed buildings.
3. Heating, hot water and ventilation
Often seen as a luxury, underfloor heating is a highly efficient way of heating a building. Capable of being installed in new build or refurbishments projects, under most floor finishes including stone, tile, timber and carpet, efficient underfloor heating operates at around 30 - 35 degrees centigrade (the same temperature as human saliva). The energy required to heat the hot water passing through the pipes system is therefore considerably less than the energy required to heat conventional radiators often operating at temperatures in excess of 50 degrees. Combined with a condensing boiler operating at 91% efficiency and factory insulated hot water storage, the energy requirements for a building can be drastically improved.
Passiv Haus technology looks to create buildings which are carbon neutral. This is achieved through various means such as using heat recovery system which re-use energy which would normally be expelled from a building and harvest the energy before inputting it back into the building or a chimney stack effect where warm air rising through a building is used to draw cool fresh air in from the outside. This often needs more specialist input and the integration of ductwork can be more problematic in existing structures.
4. Micro Generation - Renewable
Having considered the above, the production of energy can then be introduced into the design. The following are some of the potential technologies:
4.1 PV cells (Photovoltaics)
Consideration in using these include the up front capital cost, ensuring the correct orientation is achievable, government incentives and the ability to sell surplus energy back to the grid under feed in tariffs. PV's can have relatively short term bay back periods although their use in Conservation areas and on Listed buildings can be difficult.
4.2 Air or ground source heat pump.
Essentially a refrigerator in reverse, ground source heat pumps tend to be more efficient, but are more expensive and require either large areas of land or piles. Ground tends to be a constant temperature 9 – 11 degrees. Air tends to be colder when the heat pump is most needed eg 0 degrees and therefore can be far less efficient / effective.
4.3 Solar Receivers
In simple terms a black radiator fitted to the roof of a building solar receivers harvest the energy from the sun and use it to heat water. This is combined with a boiler to increase the heat as required or when no solar energy is available. Planning and design considerations are similar to PV cells.
4.4 Wind turbines
Wind turbines harvest the energy from the wind to generate electricity. Again considerations with regard design and planning are similar to PV cells, whilst surplus energy can be used to feed back into the grid.
5. Water Conservation
Whilst the need to save water may not seem as acute as a country like Spain, water is a valuable natural resource and is not that uncommon in Britain for there to be a summer hosepipe ban. More importantly the reduction of the use of hot water through for example shower heads will reduce the energy required to heat a volume of water and hence reduce the energy consumption of the building.
6. Architecture
In considering all of the above options, the impact on design, space and aesthetics needs to be carefully thought through. LPA will ensure that there is an overall and consistent approach to the integration of these technologies, incorporating them into the final scheme and design aesthetic.