Eco Design – Self-sustaining homes
From zero carbon to energy efficiency, environmental issues are not only front-page news but are increasingly mandatory considerations within the planning application process and building regulations. We are actively ensuring our design considerations, materials specification and technical support meet these new challenges, advising our clients appropriately in building sustainable, energy efficient and healthy homes. Lightening your impact on the environment while still creating stylish, modern and traditionally designed homes that benefit from the latest technology is what Design & Materials care about.
Sustainability is the key
The key word is sustainability and the Government has issued a detailed document entitled Code for Sustainable Homes, which gives a step by step guide to designing and building self sustaining, low carbon homes. In brief the document sets out design principles and includes categories such as energy/CO2, pollution, materials and water use. The code uses a star rating system to determine the overall sustainability performance of a new home starting with one star and rising to six stars. In simple language one star equates to a 10% improvement on the energy standards of the current Building Regulations and six stars represents a ‘zero carbon’ home. (For further information visit www.communities.gov.uk).
There is a wide and complex range of options open to the self builder to achieve a high rating. Calculating the rating is not a task for the layman and has to be carried out by a qualified, independent Energy Consultant. Our experienced team can guide you through the maze and advise you on the cost implications at every stage. One such consultant is Simon Bovington who has 30 years experience of the energy conservation industry. Simon says.
Importance of good design
“In the code the Government sets out 9 principle categories of sustainability to consider. Each category has a part to play. For anyone building their own home however the most important areas in my opinion, are design and specification. Good design lays the foundations for a self sustaining home and should consider key factors such as the shape of the building, it’s orientation on the site in relation to the North point, the layout of the principle rooms and the use of glazing for solar gain. The materials you use are also vitally important in terms of reducing heat loss and the storage of heat gained within the structure”.
“There is a wide range of ‘green’ products you can incorporate into your new home. My advice would be to at least investigate heat pumps, bio-mass boilers, solar panels, triple glazing and photovoltaic technology. It is worth bearing in mind that certain design features actually lose you points in the star rating system the worst of these being open fires, very large areas of glazing, mechanical ventilation systems, air conditioning units and swimming pools”. (Simon can be contacted on 01993 850 955)
We have analysed the ratings for homes we recently designed for clients and typically they have achieved a rating of 3 stars on the sustainability scale. These ratings were principally achieved through intelligent, thoughtful design and careful choice of materials and do not include additional ‘eco features’ such as heat pumps, solar panels, triple glazing or bio-mass boilers (see below*). Should you wish to incorporate any or all of these features in your new home then you can achieve a higher star rating. There are costs attached to these options and we can advise you accordingly but as with all aspects of building with Design & Materials, the choice is yours.
Design: Our key principles and objectives when designing your new home
- To make the best use of solar power and natural light.
- Add real value when compared to other houses.
- Respect local character and landscape.
- Reduce energy and water usage.
- Help you create a healthy home that maximises your wellbeing.
- Minimise waste, energy use, transportation and pollution on the build phase.
- Provide the best possible value and advice to our clients.
Optional ECO features
As mentioned above there are a number of ECO features you can incorporate when building for yourself. These will further reduce the carbon emissions from your new home and assist in attaining a higher star rating.
There are two options using the south-east to south-west aspects of the building: solar glass panels or photovoltaic (PV) roof tiles, which can be used (in part) to heat water or operate your heating system. It is difficult to attach guideline costs for these because the number and type vary. If you are interested in these systems we can explore the cost and practicality once your design has been created. ‘Payback’ time for panels is around 10 – 15 years but over 40 years for PV tiles. Image courtesy of renewable-resources.com.
Below the surface of your garden the temperature is a constant 10°C and by installing pipes and a heat pump the temperature of the water is raised, enough to power under floor heating. Typical cost is circa £10,000 for the system itself i.e. excluding the under floor heating system. ‘Payback’ time is around 10 years. Image courtesy of iceenergy.co.uk.
By far the most vulnerable area of a dwelling for losing heat is through glazed areas. We provide as standard factory fitted double-glazing filled with Argon gas to all windows. As a self-builder you have the option of specifying triple glazing to further minimise heat loss from your new home. This also has the added benefit of reducing noise pollution entering your home from external sources. It is a bit more expensive and cost varies depending on the size of the dwelling, area of glazing and window style. It should be noted that triple glazing is not particularly suitable for windows with glazing bars e.g. Georgian and cottage style.
This type of boiler burns organic materials sourced either directly from plants or indirectly from industrial, commercial, domestic or agricultural products. It does not use fossil fuels. For domestic applications the fuel usually takes the form of wood pellets. These boilers have environmental and economic advantages and are considered ‘carbon neutral’. An area for storing the wood pellets has to be planned for. For a typical 4/5 bedroom dwelling they cost on average £5,000 more than a modern condensing boiler and pay back is 5 to 10 years.
Due to turbulence in urban areas this is usually only suitable in rural locations but even then you need ‘good winds’. There are other considerations such as aesthetics and the need for planning permission.
The government currently provide grants and typically you will pay £9,000 to £13,000 (including the grant). ‘Payback’ time is similar to geothermal heating i.e. 10 years or so. Image courtesy of good-energy.co.uk.
These are fitted on your roof and channel light to darker areas of the house, the idea being you switch your lights on less often. Also natural light is always preferable to artificial. Sunpipes by Monodraught is probably the best known manufacturer. Prices start at a couple of hundred pounds.
Heat recovery/passive ventilation
This system takes the warm moist air from bathrooms and kitchens and passes it through a heat exchanger. The energy is then used to heat incoming air, which is ducted to living areas.
The heating engineer/plumber can explore the cost, practicality and efficiency when pricing for the work.
This is achieved by installing an underground water tank (or tanks) with filter and pump, to store natural rainwater, which is then used for flushing toilets, washing clothes and watering your garden.
The better systems such as Aquatek automatically monitor water levels and switch to mains when required. Cost obviously depends on the size and number of tanks but £2,000 to £3,000 is typical.
The external materials of a new house i.e. bricks/stone and roof tiles are the same for all forms of construction. Timber is clearly renewable but the blocks that we supply for internal walls and floors are manufactured from recycled waste materials. A point often conveniently ignored by those promoting the ‘greenness’ of timber framed homes.
Aside from the advantage of sound absorption, heavy dense building materials provide a high thermal mass. That means walls and floors are able to store heat, which is then gradually, released back into your home. The heat gain can be from either solar energy during the day or from your heating system. In real terms this means you can programme your heating system to come on later or switch off earlier thus saving fuel. This together with the quietness of a solid structure results in higher levels of comfort. When choosing your bathroom fittings, low flush toilets are worth consideration.