Building an Energy Efficient Home is a question of doing a few things very well
- Build it tight
- Insulate it right
- Orient it for sunlight
- Correctly install efficient equipment
Always remember that energy efficiency comes before renewables.
Don’t design in problems, design in energy efficiency. Improvement s in structural and build quality will generally have a greater benefit than good appliances.
Well sealed building is the perfect start to an energy efficient house. Minimise penetration of pipe work and cabling through the insulation shell. Consider building a draught lobby. By using a smart vapour barrier, a near airtight envelope can be built. This can then be measured by use of a blow-door test which is mandatory in the new building regulations. Air tight houses will require good indoor air quality which can be proven by a whole house mechanical ventilation system with high efficient heat recovery. Open fires should have an independent air supply.
Increased levels of insulation above the building regulations are obviously important and economically justified but what is crucial is that the improved level of insulation is installed to a high standard. That means no voids or gaps, no compressions of the insulation. Avoid thermal bridging or “short circuits” across insulation at lintels, jambs, and sills of doors and windows and at junctions where floors and ceilings meet external walls.
Try and orient the house to capture a lot of sun in the winter. Concentrate the glazing and living spaces on the southern façade. That way exposure to the low altitude winter sun can allow passive solar heating and day lighting. Thermal mass within south facing rooms e.g. masonry walls or concrete floors can absorb and store solar energy during the day and release at night. A well designed sunspace or conservatory on the south side of a house can reduce the heating requirements by acting as a buffer against heat loss.
Energy efficient houses need smaller heating systems than conventional houses. Select high efficient equipment and controls that are installed correctly. Use “A” rated condensing boilers with high efficient radiators or under-floor heating, factory insulated cylinders, zone and separate time and temperature controls. Install solar water heating to provide up to 60% of a houses hot water needs. Install energy efficient lamps and appliances. Glazing should be “low emissivity” double glazing or consider argon filled triple glazing.
If you are planning to build a house try and choose a sheltered location so that you can reduce heat loss from exposure to wind. If that isn’t possible plan to plant trees or shrubs to act as shelter. A compact build form is more energy efficient with a lower surface to volume ratio. Try and avoid dormer and bay windows as they are difficult to insulate effectively. Pitched roofs should have one slope oriented south or at least south east to south west for optimum performance of solar panels. When you have a design completed and specification outlined have a Building Energy Rating Assessor work out the BER for the house and then if necessary refine either the design or the specification of the energy products.
BER Building Energy Rating is an indication of the energy performance of a dwelling. It covers energy use for space heating, water heating, ventilation and lighting, calculated on the basis of Standard occupancy. It is expressed as primary energy unit per floor area per year.
“A” rated properties are the most energy efficient and will tend to have the lowest energy bills.