Articles published in 2008

Last month we had a look at the Kyoto targets for reducing greenhouse gas emissions. Related to these targets, though not the same, are targets for renewable energy. About the same time that last month’s magazine appeared on the bookshelves, the Energy minister, Malcolm Wicks, announced that the government supported the EU target of 20% of total energy to come from renewables by 2020 – but that the government would be negotiating with the European Commission for the UK’s target to be only 10% – 15%.

By now, readers will be all too aware that zero-carbon housing is on its way – though it will not become compulsory until 2016 (in theory).

Under the anticipated building regulations of 2016, taken over a year the net carbon emissions due to the energy used within a new house will have to be zero. The biggest challenge will be the production of carbon-free electricity, which means, for the selfbuilder, electricity derived from renewable sources.

Last month, we looked at the potential of wind power and noted that wind speed is critical. The power of the wind varies as the cube of its speed. Obstructions such as trees and buildings slow the wind and create turbulence near the ground, so a wind turbine should be mounted as high as possible. A counsel of perfection is that the turbine should be 10 metres higher than any obstruction within 100 metres, but that is not practical in most of over-crowded Britain.

Last month I wrote about the National Homebuilding & Renovating Show at the NEC. At the seminars of the H&R shows, two of the leading speakers are David Snell and Mark Brinkley. They have been doing the seminars together for many years, and their performance has developed into a finely tuned double act. David Snell is the author of ‘Building Your Own Home’ and Mark Brinkley author of ‘The House Builders Bible’.

For me, the most interesting building event of the year is the annual conference of the AECB. This year it was held in June at the University of East Anglia (in Norwich), and it was as stimulating as ever. Over 120 people attended, and they included architects, builders, developers, building energy specialists – and some selfbuilders.

Earlier in the year I wrote a couple of articles about renewable electricity. Now I’d like to look at renewable heat, with this article being about the harvesting of solar radiation for space heating and water heating. 

But before we look at space heating, it should be stressed that the first priority is to reduce the need for heating. Lavish insulation with good detailing drastically reduces the amount of energy required for space heating.

After a year’s work by himself and his team, John Callcutt presented his review of housebuilding delivery last month (November). In the audience were representatives from many of the diverse organisations involved in housebuilding. I had been invited as a representative of the selfbuild sector – I haven’t been amongst so many suits for many a year! Also present was the Housing Minister, Yvette Cooper, and in the way she answered questions she showed a good grasp of the issues involved.

Within a decade all new houses will have to generate their own electricity. Perhaps groups of new houses will be able to do this collectively, but most selfbuilds are on individual plots, and the electricity for an individual new house will have to be generated on site. It’s likely that the most common way to achieve this will be photovoltaic panels on the roof, and we looked at this method last month. Electricity can also be generated by the wind, and on some sites this may be a feasible option. Indeed, a wind turbine in a windy position is likely to be more cost effective than a PV array.

The original selfbuild show celebrated its centenary earlier this year – the first Daily Mail Ideal Home Exhibition was held in Olympia, London in 1908. The show included a competition to design the ‘ideal home’, and subsequently the Daily Mail Book of Home Plans was popular for decades, being regularly updated. In those early days you could build anywhere and land was cheap, so what is today the biggest barrier to selfbuilding – the lack of individual building plots – was then no barrier at all. However, after the Second World War, plots became limited by the new requirement for planning permission, and building materials were rationed, so selfbuild became difficult. The annual Exhibition became more of what it is today, a consumer show for the house proud.

At the recent Homebuilding & Renovating show at the NEC I interviewed two of the leading selfbuild experts. Last month, I wrote about one of them, David Snell. This month, the article is about my interview with Mark Brinkley.

The ‘Passive House’ movement had its origins way back in 1988, in a dialogue between two academics, Dr Wolfgang Feist of the Institute for Housing and the Environment (in Germany) and Professor Bo Adamson of Lund University (in Sweden). They thought that if a house was well enough insulated and its ventilation was by an efficient HRV system (Heat Recovery Ventilation), then the house would stay warm in winter without any need for an active heating system. Incidental heat gains from appliances and people together with solar heat gains from windows would be enough to keep the house warm.

In my overview of solar heating last month, we saw that the immediate financial return of installing solar water heating is disappointing: something like 2% pa if the fuel saved is gas, and about 6% pa if the fuel saved is electricity. But even if you are building now, solar water heating still warrants consideration. It seems likely that the price of gas and electricity will be increasing for many years to come, and the price of retrofitting a system is about 30% more than installing in new build. Moreover, a solar system appreciably cuts carbon emissions, and this can improve the Energy Performance Certificate of your house.