Energy efficiency and eco friendliness are two important issues for those looking to build for themselves. As a self-builder you have infinitely more input and control over these matters than those buying a ready built home.

Carbon footprint
The UK is no longer self sufficient in energy and what we pay as individuals is rising year on year. Cost and future availability are therefore most definitely factors. So too is the impact that energy consumption has on the environment and any responsible citizen will be looking at ways to reduce their carbon footprint. Finally there is the issue of how these affect the 'liveability' and comfort of your new home.

So what are your options and what are they likely to cost?

Intelligent design
Design is the natural starting point for building an eco-friendly ('green') home. The orientation of the house on the plot, careful planning of the principal rooms and thoughtful positioning of windows all combine to increase energy efficiency and levels of comfort. This is another good reason for considering our bespoke approach to designing your new home.

Thermal efficiency
Over the last 10 years in particular the Government has introduced ever more stringent Building Regulations aimed at forcing house builders (developers and individuals) to make new homes more energy efficient i.e. emit less carbon. The most recent being the changes to Part 'L' of the legislation introduced in April 2006.

Tailored thermal packages
However the self-builder has the option of further improving the thermal performance of their new home by increasing the recommended levels of insulation permanently built into the structure - at a cost of course. If this is an area that interests you then we can tailor a package to suit your requirements and tell you what it will cost.

Example: We currently provide our clients with a minimum 'U' value for the external walls of 0.24 W/m²/°C. This can be reduced to 0.15 W/m²/°C and for a family house of 250m² the additional cost is around £9,000. This compares very favourably with the SIPS system much vaunted by the timber frame industry. Payback time 5 - 10 years.

Solar energy

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

Geothermal heating
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

Wind turbines

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

Lightpipes
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.

Rainwater harvesting

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.

Building materials
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.

Increased comfort
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. For more on this see my article on the benefits of modern masonry construction Click here.

Tom Somerville
Company Architect