1. Choose an architect who understands energy efficient home design

• Make sure builders are aware of your home’s low energy goal
• Choose dealers who have knowledge and experience in energy efficiency
• Remember that many architects/builders do not go beyond the minimum building standards and regulations, but the minimum is not the most efficient.

Minimize your heat loss:

• Keep your house plan simple and compact: A compact house without extensions will have less heat loss due to the reduction of external walls and roof area. Remember that single-story houses like bungalows lose more heat through the roof than two- or three-story houses where rising heat is used at all levels before reaching the roof.
• External walls must have high level insulation
• Make sure there is good controlled ventilation and draft protection.
• Your architect can provide you with energy estimates of expected annual fuel bills

Maximize your solar heat gain:

• Build along the east-west axis – An energy efficient home will capture free energy from the sun to heat your home and water. Ideally, when possible, choose a site where your home can face the sun (external shades can prevent overheating in the summer months) and be sheltered from prevailing winds.
• Homes in the northern hemisphere should locate most windows on the south side with a reduced window size on the north side, and vice versa for homes in the southern hemisphere: most windows should face the sun side to benefit from solar gains. However, some windows will need to be on the non-sun side to allow good natural light into all rooms of your home.
• Kitchens and breakfast rooms are used primarily in the mornings, so for homes in the northern hemisphere, a southeast orientation will take advantage of the morning sun. For houses in the southern hemisphere, a northeast orientation will take advantage of the morning sun.
• Hallways, stairs, and bathrooms can be located on the side that doesn’t get much sun, as they are used less often.
• Locate living rooms and master bedrooms on the side facing the sun
• In two-story homes, consider having your bedrooms on the lower level (cooler for sleeping) and your living rooms on the upper level, further reducing your heating requirements as the floor above heats up.
• Use the energy of the sun
  • Wind turbines can take full advantage of wind power generation
  • Heat pumps use the sun’s energy: all renewable energy systems are complementary to an energy efficient home design.

Install an efficient heating and hot water system:

• renewable energy systems
• Solar heaters
• Use a condensing boiler if you use gas or oil
• Install easy-to-use controls

You can find more information about these on the Home Heating Systems and Solutions site.

Consider the thermal mass

• When thinking about an energy efficient home, remember that the use of certain materials will also improve the ‘thermal mass’ of your home by their ability to slowly absorb solar heat during the day and then slowly release this free heat at night – Materials Common ones used for thermal mass are:
  • Adobe bricks (mud or earth bricks)
  • rocks and stones
  • concrete (preferably concrete with stone)

  This is because they have:

  • High Specific Heat: Capable of storing a large amount of heat over a long period of time like the heat bricks in a sauna.
  • High density – basically the weight (mass) of a material relative to its volume (its size) – the greater the mass per unit volume, the greater the density
  • Low thermal conductivity – slow absorption and slow release of heat
• Thermal mass is not insulation, it is the amount of specific heat that can be stored in a material (water has a high thermal mass as it can store a lot of heat). Insulation materials have lower thermal conductivity to restrict heat flow and absorption.

isolation

• The percentage of heat loss from a house is approximately:
  • 42% ceiling
  • 12%windows
  • 12% Unlocked chimneys and drafts around doors
  • 24% walls
  • 10% floor
• So when you think about building an energy efficient home, understand that installing insulation at the construction stage is the easiest and cheapest way to improve the energy efficiency of your home.
  • You can upgrade standard timber framed walls by using 140mm studs instead of 90mm studs; This will allow you more insulation. Masonry cavity walls can be improved by filling with insulating polystyrene foam and using lightweight thermal blocks.
  • You must have at least 250mm of loft insulation, 100mm of insulation between joists and 150mm of insulation at the top. Loft conversions require careful attention, especially if dormer windows are installed, but a high level of insulation can still be achieved.
  • Soil heat loss varies with soil type. However, ground floor insulation is quite easy. Usually a 125mm polystyrene layer/sheet is used. This size will be increased if underfloor heating is installed to minimize heat loss.
  • Make sure insulation overlaps between elements, for example between the wall and the attic/ceiling cavity
  • Make sure air gaps, such as wall cavities, are free of debris that can be salvaged and thus compromise the insulating air gap.
  • Make sure fiber insulation materials are not compressed (packaged tightly) as this will undermine their ability to insulate properly
  • Make sure all insulating materials are kept dry.
  • Be sure to seal all the holes where services such as water and gas pipes enter your home.

Windows & Conservatories

• You will always lose more heat through windows than through walls, especially single pane windows. To minimize heat loss through windows, ‘Low-E’ coated double glazing should be installed in all new homes.
• Double glazing not only reduces heat loss but also offers some sound insulation. With double glazing, the two panes are usually vacuum sealed. However, you can get argon filled (gas filled) triple glazed units which are worth considering if you can afford them.
• Conservatories can save you some energy by acting as a buffer between the adjoining wall by trapping heat from the sun, thus reducing heat loss from the room separated by the adjoining wall. To be effective, greenhouses should be located on the sunny side of the house and preferably not shaded by trees or other buildings.
• Properly placed greenhouses should not require permanent heating, but the doors separating the house from the greenhouse should be double-glazed and closed when not in use.

Efficient home heating

• A well-insulated house is a low-energy house, which means that the heating requirements of an energy-efficient house are lower than those of a similarly sized house that is poorly insulated.
• Your heating system must take into account:
  • Fuel source and availability
  • The time you will spend in your home: fast or slow response systems
  • Construction material: Wood-framed houses should have sensible heating, such as radiators or air-source heat pumps, since wood retains less heat than concrete, for example.
  • Underfloor heating systems are not suitable for houses built with lightweight building materials, such as wood frames, due to their slower heating response.
• You can have hydronic (wet or water) underfloor heating systems combined with radiators. These are generally designed with the underfloor heating on the ground floor and the radiators located on the upper floor.
• Solid tile floors work best with underfloor heating. If you prefer a softer floor finish instead of tile, you should consider rugs instead of rugs for better heat transfer/escape within the room.
• Renewable energy systems, such as heat pumps and solar heating, are perfectly suited to energy efficient home designs.

Ventilation

• Ventilation is an important aspect that should not be overlooked as it provides fresh air and removes stale air and moisture. The removal of moisture prevents bacterial growth, thus maintaining a healthy living environment.
• Kitchens should have exhaust fans or passive stack ventilation (PSV). The PSV works on the principle that hot air “rise” and carry stale air up and out.
• Mechanical ventilation systems with heat recovery offer filtered air and reduced noise intrusion as windows can be kept closed. However, unless you are using a renewable energy system, such as photovoltaic (PV) or wind turbines, the energy required to run the fans rules it out as a feature of an energy efficient home. Also, for a heat recovery system to work efficiently, the house must be well sealed.
• All rooms must have drip ventilation, which allows air to enter at a trickle rate to provide the room’s air change rate per hour (ACH).

lighting and appliances

• These should have a low energy (low power) rating, saving you money on running costs and helping the planet by reducing CO_two transmissions

So now you can save the planet and cut running costs by building an energy efficient home.