Orientation of the sun
http://www.smarterhomes.org.nz/design/orientation/
I will orientate the house to take advantage of warm sun and cooling breezes, thereby achieving greater comfort at lower cost.
In general, ideal orientation means:
- You get the right amount of sun - plenty in winter and in cooler climates, not too much in summer and in warmer climates.
- You get the right amount of sun - plenty in winter and in cooler climates, not too much in summer and in warmer climates.
- You're protected from strong/cold winds but can take advantage of breezes to cool the home when it is too warm.
Positioning for sun
To make the most of the sun for warmth and natural light, the house's main living areas should face north. The main glazing in the house, such as windows, skylights and glass doors, should also face north. Anywhere between 20ºW - 30ºE of true north is ideal. I'll want less glazing facing west because of the potential for glare and overheating from late afternoon sun. This is an increasing problem in New Zealand houses. East-facing glazing captures morning sun and can be sized according to preference for light, heat control and ventilation in summer. South-facing windows receive minimal sun and should be relatively small to avoid heat loss but allow for light and ventilation.
To make the most of the sun for warmth and natural light, the house's main living areas should face north. The main glazing in the house, such as windows, skylights and glass doors, should also face north. Anywhere between 20ºW - 30ºE of true north is ideal. I'll want less glazing facing west because of the potential for glare and overheating from late afternoon sun. This is an increasing problem in New Zealand houses. East-facing glazing captures morning sun and can be sized according to preference for light, heat control and ventilation in summer. South-facing windows receive minimal sun and should be relatively small to avoid heat loss but allow for light and ventilation.
The exact amounts and proportions of glazing will vary depending on other considerations such as climate, how well insulated the house is and how energy-efficient the glazing is. It is also worth considering the type of glazing alongside the placing and number of windows – for example, if I want larger south-facing windows to capture the view, I might want to have these double glazed, or I might consider tinted glass for west-facing windows. The exact amount of heat the house gets from the sun will depend on the season, time of day, weather, local climate and rate of air pollution. Heat is greatest when the sun is at a high angle relative to the horizon (i.e. it's higher at noon than at dawn or dusk). Heat is also greater in summer than winter.
Even if the house doesn't face due north, windows can be positioned to get north sun.
Buildings, trees and terrain that block the sun
To make the most of the sun, the house should ideally be positioned as far as possible from neighbouring buildings, terrain or vegetation that might block north sun:
To make the most of the sun, the house should ideally be positioned as far as possible from neighbouring buildings, terrain or vegetation that might block north sun:
A site that slopes north will get more sun than a south-facing slope. A south-facing slope will be more shady, which may be useful in summer but restrict the ability to make the most of the sun's warmth in winter. A site that runs north-south should get sun throughout most of the day. Neighbouring homes won't generally block the sun during the middle of the day, but they may provide shade in early mornings or late afternoons if they're close to the boundary. A site that runs east-west is more likely to have its north sun blocked by neighbouring houses. However, this depends on how wide the site is and how close neighbouring homes are to the boundary. If a north-facing site is too narrow, i'll have limited ability to place living areas along a large north wall. Make the most of morning or afternoon sun in a number of rooms. Note that in winter, objects cast shadows two to three times their height, so if possible the house should be sited well back from anything that might block the sun. Building along the southern boundary is a good idea if the local council permits it.
Neighbouring buildings can block winter sun. If possible, build the house a sufficient distance away from buildings and other obstructions. Note that in winter obstructions will cast shadows two or three times' their height. Even if the site isn't ideal for catching the sun (for example because it slopes south), it may be possible to maximise the sun's warmth using north-facing clerestory windows or other glazing.
Clerestory window to bring north sun into a south-facing home.
Shade
If I orient the house to make the most of the sun, I can use shading and ventilation to keep the home cool in summer. Because the sun travels higher in the sky in summer and lower in winter, I can use features such as overhanging eaves and vegetation to ensure I get don't get too much sun in summer. I can also position the home to get shade from neighbouring homes, terrain or trees when the sun is at its hottest, such as late afternoons in summer.
If I orient the house to make the most of the sun, I can use shading and ventilation to keep the home cool in summer. Because the sun travels higher in the sky in summer and lower in winter, I can use features such as overhanging eaves and vegetation to ensure I get don't get too much sun in summer. I can also position the home to get shade from neighbouring homes, terrain or trees when the sun is at its hottest, such as late afternoons in summer.
The sun travels higher in the sky in summer.
Letting in breezes, keeping out wind
From southerly gales to northwesterly blasts, wind is an issue in many parts of New Zealand. Ideally, I'll orient the house in a way that avoids the strongest and coldest winds - but still allows the ability to harness mild breezes to keep the occupants cool in summer. Vegetation can be used to filter harsh winds, and landscape and building structure can be used to deflect cooling breezes into the interior but exclude harsh winds. Other features such as well-designed windows will also help.
From southerly gales to northwesterly blasts, wind is an issue in many parts of New Zealand. Ideally, I'll orient the house in a way that avoids the strongest and coldest winds - but still allows the ability to harness mild breezes to keep the occupants cool in summer. Vegetation can be used to filter harsh winds, and landscape and building structure can be used to deflect cooling breezes into the interior but exclude harsh winds. Other features such as well-designed windows will also help.
When thinking about orienting the house to catch breezes and avoid wind, consider:
- Whether there is a prevailing wind direction (vegetation patterns can sometimes indicate this, or ask the neighbours; coastal breezes are usually from an onshore direction)
- Whether there is a prevailing wind direction (vegetation patterns can sometimes indicate this, or ask the neighbours; coastal breezes are usually from an onshore direction)
- Whether the wind changes with season - in terms of direction and strength
- Whether the wind strength or direction changes at different times of day - for example, in hilly areas cool breezes often flow down valleys in late evening and early morning
- How exposed the site is to wind - winds are stronger near coastal areas and ridgetops
- How exposed the site is to wind - winds are stronger near coastal areas and ridgetops
- Whether the strength is affected by nearby buildings, hills and vegetation - buildings and valleys can funnel winds (which makes them stronger), and hills and vegetation can provide shelter.
As well as sun and breezes, I will also need to consider orientation to:
- Take advantage of views
- Take advantage of views
- Avoid noise
- Achieve privacy
- Achieve the appearance I want for the house
- Ensure there is clear street access
- Beware of west-facing views. If I orient the house west, it will get the full glare of late afternoon sun and it may also be exposed to strong winds.
Striking a balance
No comments:
Post a Comment