The term eco home is used broadly to describe any house which has been designed with sustainability or environmental concerns in mind. This can range from kitting your home out with the latest renewable technology for heat and power, to building a home that has a low energy demand in the first place.
With so many factors to consider, eco homes are deemed to be a complicated endeavour. However, sustainable design falls into a few keys areas outlined below.
A fabric-first approach means focussing on reducing the potential heat loss of a building. This requires you to think about what to build out of, how to insulate it, and how to ensure airtightness (which has a direct impact on heat loss).
Certain build systems have been designed to incorporate insulation as part of the structure (rather than something that is added into wall cavities or behind panels). Structural insulated panels (SIPs) and insulated concrete formwork (ICF) are two such examples.
Those who build a thermally efficient house will also want to think about the orientation of the house for solar gain. This will dictate the positioning of windows (lots on the south-facing elevation and fewer on the colder north-facing elevation).
Letting in as much sun as possible will naturally heat the house and lower the demand for heating. However, too much sun and your home can overheat, so many use louvres over windows to control solar gain.
For some renewables are a necessary feature for eco homes, but as outlined above, your focus should be on producing a home with low heat demand to begin with. That said, while you can easily design in ways to control the temperature of your home, you may want to turn to renewables for power to light your home at night (and power any appliances). Solar photovoltaic (PV) panels can be used to generate some of this energy demand. Wind turbines and hydroelectric can generate electricity too, but these are often much more expensive.
Even a very thermally efficient house needs hot water and maybe the odd boost of heat, and there are ways to generate heat for your home without the need for a conventional gas-mains boiler. These are listed below (with links through to more information on them):
All of these have their pros and cons, but on the whole will decrease your reliance on fossil fuels, which can only be a good thing.
If you are looking to really reduce your environmental impact, limiting your energy demand is only half the story. What about the impact of what your home is made from? Getting into the sustainability of materials is a bit of a can of worms — you might be able to find materials from sustainable sources but if they need to be shipped from miles away, that is going to increase your carbon footprint.
Unless you build entirely ‘from the land’ you will have to accept that the eco warrior in you will have to make the odd compromise. However, where you can, buy local, natural materials and look out for certificates of sustainability — such as the Forest Stewardship Council (FSC) mark on wood.