We rebuilt out house as "carbon neutral" as we could in 2005 - the work took most of a year - it was essentially a managed "self-build". We are on decent hill in the South of England, exposed to the prevailing winds and with a large area of South-facing roof & land. I am especially interested in the whole life-cycle of any materials and products we used. I monitor all energy use in the house, by room & function, day by day. All wood (mostly green oak) & stone etc. was sourced locally. 22,000 roof tiles were hand made from local clay... there is not a single piece of composite board in the house.
I spent 4 years in the planning & evaluation of technologies. Whilst investigating the energy consumption side I spent time at the Centre for Alternative Technology (CAT) in Wales ( http://www.cat.org.uk/ ) - this is the premier research organisation in the UK for this stuff and one of the most respected in the world - I remember when they were set up years ago - a bunch of hippy tree-huggers with painted VW camper vans living in a forest! Now its hugely respected and part of the university of Wales... how times change... Anyway, they have a wealth of experience, so I went and spoke with them... they confirmed what I had been researching, namely, for us: 1. Even though we are one of the highest points in the SE of England and have enough wind throughout the year to drive a domestic turbine, there is no plausible economic argument (other then feeling good) for a wind turbine - their conclusion was that it is far far better to buy "green" electricity from someone who can do it on a commercial scale. Turbines come with a number of issues, especially WRT energy storage and how that is achieved... 2. At the time, photovoltaic was completely insane in its pricing - CAT had a brand new 15kW roof that cost more to build than the house it was on and has the same storage issue as a wind turbine. PV also only works during the day and is notoriously fickle with respect to UK weather. Today, technology has moved on, the Chinese are driving the market price down and there are government grants for PV panels in the UK, but its still a long long way for economic sense if you can buy green electricity from a utility. 3. Solar heating with panels on the roof etc. No sense (still) in this at our latitudes (50N). Payback is still in the 20 year bracket and the plumbing adds complexity to the house. Now, I like the KISS principle - I don't want a house full of technology and banks of lead-acid batteries that'll be redundant in 5 years and complexity inevitably leads to problems. So what does work? 1. Insulation. Lots of it. Eco-friendly if you can - sheep wool is good, but very expensive. Straw is amazingly good and there are other similar alternatives. Many of the foam-based products sweat formaldehyde and give off nasties if burnt. Make sure your key energy users are as efficient as they can be. Fridges, in particular, are a nightmare for energy consumption - in the UK, up to 20% of a house's electricity usage can be the fridges. Replacing an old fridge (complete with its CFCs etc.) with a AAA-rated one is a BIG step. 2. Ground/Air source heat pump. This is the main system that we use for all our hot water and heating (underfloor and standard emitters). Essentially just a glorified fridge. Highly efficient (especially as we have 3-phase power so more efficient compressors can be used). Standard plumbing - just a slot-in for a standard boiler. Works day or night down to -30C. Very cheap to install (partly because it we already had diggers on site to bury the coils), No maintenance - sealed for 20 years. 3. Very careful thought WRT lighting. Many low-energy bulbs contain mercury and have a dreadful power factor, which is not good, but by choosing your technologies carefully, we've radically reduced power on that front. We have some LEDs, mostly for mood lighting, but they can't economically replace GU10s yet - every month this area improves, so in a year or two, LEDS may be viable. Other technologies are also improving. 4. Use energy saving modes on all equipment - contrary to much rambling on the web, newer flat-screen TVs etc. use only 2W or so in standby, but computers burn it up, especially if you take an "annual" view. Having all the kids PCs & games consoles etc. go into standby after 15 minutes helps greatly (especially when you have a lot of them) - getting disks to spin down, screen to turn off, using efficient UPSs, having printers go into hibernate etc. all helps greatly - you'd be amazed at the annual cost of these things if you don't do this. - I estimate each of my sons' rooms cost GBP 80 pa. in electricity before energy saving, now down to about GBP 50. Don't forget those fridges! Run the dishwasher & clothes washing machine at night during off-peak usage. Loads of other stuff was done too, but the above are some of the main "wins". Looking at or energy plan now compare with the previous house, we use less energy now for a house that is over twice the size. A good-sized 7-bedroom house on an exposed site costs about GBP 1800 pa to heat, light & run - at that's with 3 kids playing lots of sport so between 5 & 10 showers/baths a day. The payback time on the heat pump was approx 3.5 years - its by far the biggest consumer of power in the house but has a power factor of very close to 1 and is way more efficient than any other option - it just marches on without breaking step and without any maintenance or adjustment... if it does break, all the parts are pretty standard, and it's cheap to fix... Cheers Nick -- You received this message because you are subscribed to the Google Groups "neonixie-l" group. To post to this group, send an email to [email protected]. To unsubscribe from this group, send email to [email protected]. For more options, visit this group at http://groups.google.com/group/neonixie-l?hl=en-GB.
