• Introduction
• Energy, Power & Renewable Energy
• Energy Efficiency & Saving
• Domestic Solar Water Heating
• Domestic Space Heating
• Wind Power
• Solar Resources & Photovoltaics
• Hydro-Electric, Wave & Tidal
• Grid Linked Systems

Energy Efficiency & Saving

• Energy efficiency is key to all (renewable) energy systems. Efficient systems are cheaper, smaller and produce the required output more reliably.
• All reductions in energy consumption:
  • reduce carbon emissions
  • reduce air pollution, thus positively impacting on health problems related to smog (1)
  • reduce acid rain, thus improving forest and lake ecosystems and habitats (2)
  • improve energy conservation in housing stock which will reduce fuel poverty (3)
• Heat loss (U) is heat flow in Watts through 1m² at 1℃ temperature difference between surfaces. A lower U-value shows better insulation. Expressed in W/m²K.
• There are many simple ways to reduce your energy needs (4).
• Between 8% and 10% of household electricity supplied is used by equipment on standby!

Conserving heat energy can be achieved by designing for solar gain, using buffer zones such as porches, adjusting and improving heating controls, and most importantly the proper installation of insulation. Open fire places are very bad for heat loss retention, i.e. a significant proportion of heat in the house goes straight up the chimney!

Heat losses through the fabric of a house make up to 70% of total losses. The typical breakdown is 25% walls, 25% glazing, 10% roof and 10% floors. Improve the thermal envelope by appropriate use of insulation.

Low-emissivity double glazing that reflects heat back into the room is more than adequate for typical UK situations.

UK housing stock is very poorly built and insulated. Compare your home with the German passive house standard (5). Of particular note is that a conventional heating system is not required. Instead, a heat recovery ventilation system is employed which may include a small heating element.

Air conditioning is often installed without proper (or any) consideration of alternatives. Avoid having air conditioning and heating on at the same time by setting temperature controls for both systems appropriately, e.g. a 5℃ difference between heating system switching off and the air conditioning coming on. The air conditioning system will also require regular maintenance.

Modern, "intelligent" electricity monitoring systems allow for real-time monitoring. Although fairly expensive, by identifying energy "hot spots" in the home, the purchase cost can be recouped easily within months (6).

1. UK Air Quality
2. Acid Rain Impacts
3. Achieving the 40% House Scenario
4. Take Action on Your Energy Savings
5. Wikipedia Passive House
6. Energy Saving Products

For inspiration, visit