Friday, October 26, 2007

True low carbon or eco-chic?

Probably since the oil crisis of the early 70's there has never been such a high level of public awareness and engagement in all things 'environmental', not least in greening up homes. In particular the UK Government has made a commitment for all new homes to be 'zero carbon' by 2016, an ambitous target which would make UK building regs on energy efficiency some of the toughest in the world, even exceeding the current high standards which exist in Canada, Scandinavia and Germany.

The problem is that new homes accont for just 1% of the housing stock annually at the current UK build rate, so what can the majority of the population do to reduce consumption and 'do their bit'? There is a huge amount of information out there and a good starting point is The Energy Savings Trust, but it can be a minefield as to what actions/technologies will truly bring genuine savings in energy, carbon and money. Here's a few ideas:

1. Insulation and draft-proofing/airtightness - do this before anything else, especially on the detailed design of a new build or extension. Usually, money spent on this has a much quicker payback than any of the technologies described below. For example, £2k spent on a mini wind turbine buys a huge amount of insulation and will payback much quicker.

2. Rainwater harvesting (for toilet flushing, laundry etc) - unless gravity fed or pump free, this probably isn't worth the cost or effort and will increase your energy consumption. Whilst saving mains supplied potable water which has used energy in its processing and delivery, it is unlikely that the energy used to do that by your water supplier will be less per cubic metre than by using a water harvesting system. Furthermore, if you are on a water meter the energy costs in operating such a system may not even be offset by the saving in water costs.

3. Mini wind turbines (fixed to house) - in most cases probably not worth the bother, but in some cases (rural, wind-swept property with no nearby obstructions) might produce useful power.

4. Mini wind turbines (standalone for farms etc) - worthwhile on windswept, unobstructed sites.

5. Solar panels (hot water) - useful and can provide up to 60% of annual hot water needs. Payback can be less than 10 years, but don't overpay for system (should be ca. £2,500).

6. Solar panels (PV, electricity generating) - expensive and long payback, but very reliable (we have them) and beautifully simple. Most cost effective on building integrated applications. A better choice than roof mounted wind turbines for electricity generation in most cases.

7. Heat pumps - good choice for well insulated rural new builds with underfloor heating not connected to mains gas. Be careful over promises of '75% savings' - they still need electricity to drive the pump!

8. Wood burning stoves - go for it! In the vast field of alternative energy, the joy of watching carbon-neutral fuel being consumed by fire within the highly efficient combustion chamber of a modern wood burner is rivaled only by the gentle rotation of 150ft wind turbine blades! If you use an open fire, three quarters of the energy in the fuel you feed it goes up the chimney; in a woodburner, three quarters stays in the room, not to mention considerably reduced emissions.

1 comment:

Anonymous said...

I've just located your blog and am reading from the very beginning and found this section very useful. We are in possession of a plot with revised plans in the hands of planners (fingers crossed for the approval decision) and are trying to find our way through the minefield of technologies to enable us to be efficient in costs, energy use and generally as green as we can make our new home so this honest opinion of the techonolgies available was very timely and helpful. I can see our new build heading the way yours has. The original planning was approved May 2007 for the previous owners, we purchased the land in November 2007 and have been trying to get the plans adjusted to suit our needs ever since!! We will prevail!! Now I'm going to carry on reading.......