22 Common Myths in Design, Cost, Lights, Windows, Insulation and Weather Proofing, Heating and Cooling, Water and Landscaping.
Myths and misunderstandings about good design have prospered. They exist as the architectural equivalent of 'old wives' tales'. This fact sheet should dispel some of the common myths.
DESIGN
1) Myth: If you can't design the perfect sustainable house there's no point bothering at all.
House performance varies across a spectrum, from very good to very bad. Incorporating any element of sustainable building practice will make a difference. Simply specifying the optimal eave widths on a project home or renovation may prevent unwanted sunshine overheating your home in summer. This step on its own will improve your thermal comfort and reduce your energy bills. All home design includes compromises, but try to do what you can to incorporate good design features.
2) Myth: Sustainable Design is just for "Greenies".
Everybody benefits from good home design. Occupants from all walks of life now enjoy lower energy bills and improved comfort thanks to good design features. Everybody on the planet will benefit from reduced greenhouse emissions and better use of limited resources. Passive solar homes can look like any other.
COST
3) Myth: Good Design costs more.
Good design in many cases can cost less than bad design. Good design is nothing new, extra or onerous. Good design is largely about the intelligent use of space and materials. The greatest gains are made in planning and orienting the home appropriately and working with the climate and existing landscape.
4) Myth: The up-front cost of efficient fittings is too high.
While efficient products sometimes cost more, most are comparable in cost with standard items of similar quality. They also have lower running costs. Most efficient products are also premium products in terms of features and warranty, etc. In many instances, the most efficient products are not necessarily the most expensive. For example, efficent space heaters which heat only the rooms in use are often a cheaper option than central heating which heats the whole house. An energy efficient house will similarly reduce the size of the heating and cooling systems required.
LIGHTS
5) Myth: 'Low voltage' lamps and downlights (12V dichroic) are energy efficient.
These lights are low voltage but not energy efficient. While low-voltage lights provide more light than ordinary incandescent light globes for a given amount of electricity, fluorescent lights are far more efficient. They deliver over four times more light than incandescent globes using the same amount of electricity. Downlights may also penetrate ceiling insulation, resulting in greater heat losses in winter. Fluorescent tubes and compact fluorescent bulbs are truly efficient.
6) Myth: Switching fluorescent lights on and off frequently shortens the life.
This is generally true for all types of lamps. High quality electronic ballast fluorescent lamps incorporate special start-up features which have minimised this problem. It is usually advisable to turn a fluorescent light off if it's not going to be needed for 15 minutes or more.
7) Myth: Fluorescent lamps take a long time to come on.
Some lamps will take a second or so to switch on. This is a design feature to avoid cold starting and lengthen their life. Instant start lamps may have a shorter life. Manufacturers are trying to reduce start-up times. Fluorescent lamps will take a minute or so to reach their full brightness and therefore may not be appropriate where instant lighting is required, but high quality electronic ballast fluorescent lamps 'warm up' more quickly.
8) Myth: Fluorescent lamps flicker.
Magnetic ballast lamps may have a noticeable flicker. More modern, electronic ballasts operate at very high frequencies and usually have no noticeable flicker.
9) Myth: Turning fluorescent lights off and on uses more energy than leaving them on.
While this may be true for older magnetic ballasts, with modern electronic controls it no longer applies.
10) Myth: Fluorescent lamps are bad for the environment because they contain mercury.
All fluorescent lamps contain some mercury but this is being reduced all the time. Far more mercury (and other pollutants) are released into the atmosphere from burning coal to provide the power for inefficient incandescent lamps.
WINDOWS
11) Myth: Large north windows are always a great idea.
Poorly designed, inappropriately glazed or shaded north windows can lead to overheating. Moderately sized north windows are a good idea where winter sun is available to warm your home. Since windows and their shading and coverings can be expensive, reducing window area to an appropriate size can reduce the cost of your home.
12) Myth: Laminated glass is as effective as double-glazing in stopping heat transfer.
10mm thick laminated glass is only marginally better than single glazing for reducing heat transfer. It is, however,
as effective as double-glazing in reducing noise transfer.
If you want to reduce noise and heat flow, double glazing is the best option.
INSULATION AND WEATHER PROOFING
13) Myth: Heavy materials such as brick and earth provide insulation.
Heavy materials are generally not good thermal insulators. They do not decrease heat flow as does reflective or bulk insulation. Heavy materials do slow the passage of heat through the building fabric, and this can be beneficial in both winter and summer where there are large temperature differences between day and night.
14) Myth: Bricks are weatherproof.
Most bricks allow moisture to pass through them. Cavity wall construction was devised to protect the inner wall from being damaged by moisture penetrating the outer brick skin. The outer brick skin is attached to the inner skin with cavity ties to provide strength. Water that penetrates the outer skin is shed via a drip groove. Brick is most useful on the inside where its thermal mass can help stabilise internal temperatures.
15) Myth: There's no point insulating walls, because all the heat just flows through the windows.
Adding insulation to one part of a home won't increase the heat losses through other parts. Although windows can be areas of great heat loss and gain, all insulation makes a difference by reducing heat flow. Insulated surfaces stay at a temperature closer to the indoor air temperature and therefore create a more comfortable environment.
16) Myth: Plastic pipes don't need insulation.
Many plumbers believe that plastic hot water pipes don't need insulation because plastic feels like an insulator. Although a better insulator than copper pipes, they still lose a lot of heat and need to be insulated. Insulation is often the most cost effective way to reduce heating and cooling.
HEATING AND COOLING
17) Myth: A few draughts here and there don't make much difference.
Draught sealing around doors and windows can save up to 25 percent of heat losses and gains in many climate zones.
18) Myth: Roof ventilators will keep your house significantly cooler.
Roof ventilators do not make an appreciable difference to house temperatures if the roof is insulated, particularly if reflective insulation is installed. If your ceiling is uninsulated a ventilator might make a small difference, but insulation is a better investment. There may, however, be other valid reasons for installing roof ventilators such as moisture removal.
19) Myth: It is much better to have an oversized heater or cooler because it's better to have them too big than too small.
An oversized air conditioner not only costs more to buy but cannot dehumidify air properly. It will only run for short periods and not have time to remove much moisture from the air. Consequently, the occupants feel sticky even when the air conditioner is running. Most air conditioners are less efficient when running at part load, and frequent cycling on and off may shorten their life. Oversized heating systems cost more, and will give bursts of heat, followed by long periods when no heating is occurring. Occupants are subjected to varying levels of heat and cold, especially when sitting near a window, where the temperature falls faster than it does near the thermostat. Appropriate sizing of heating and cooling equipment can save on purchase and running costs.
20) Myth: Air conditioning should be set at a constant temperature (eg. 22°C) all year round.
Human physiology enables us to adapt to seasonal and geographic changes in climate. Most people live in houses, drive in cars and spend time outside where the air is not constantly conditioned to 22°C. In winter 22°C may feel too hot and in summer it may feel too cold. People living in hot regions (eg. Darwin) will have a greater tolerance for heat and may find that a much higher temperature than 22°C feels right for them. In winter turn the thermostat down a few degrees, and in summer up a few degrees. Each degree can reduce energy consumption by up to ten percent.
WATER
21) Myth: Water efficient shower roses don't give a good shower.
While many early models of water efficient shower roses performed poorly, new models with the AAA efficiency rating have to meet minimum quality performance levels specified by Standards Australia. The AAA rating is a guarantee that you will get a high quality comfortable shower while using up to 50 percent less water.
LANDSCAPING
22) Myth: It is always better to plant native trees around the house rather than exotics.
Non invasive, exotic, deciduous trees can perform a vital valuable role in regulating the heating and cooling of a home. When planted to the north of a home they shade in summer and admit sunlight in winter. Try to choose varieties that will attract native wildlife to your garden.