Image: Baxter Homes
Do rising energy costs and global warming get you hot and bothered? Well, you’re going to love our cool natural ventilation solutions.
Going natural is not only a better choice for our planet than air conditioners, it’s absolutely free, and it makes keeping your home cool and comfortable all year-round a breeze – literally.
The first step is choosing the right type of windows, the second is to put them in the right place to encourage air movement and cross ventilation breezes.
Of course, this is all well and good if you are building or renovating. Passive cooling should be considered along with passive heating early in the design process. But what can you do with your existing home?
Well, you can start right now. Go ahead, check out which way the wind is blowing and open a window for some fresh air!
Let your home breathe, it will reduce mould-causing moisture, and get rid of all sorts of nasty things that make for bad air like dust, pollen, and other air-born pollutants.
Now, open another window and you’ll get a bit of natural cross ventilation going on.
Cross ventilation relies on air being able to flow freely from one side of the house to the other.
The best way to do this is to position doors and windows on walls that catch cooling prevailing winds. On the coast, breezes usually come from an onshore direction, in the mountains they usually travel downslope. Generally, they tend to come up in the late afternoon or early morning.
It’s common to think that winds blow through your home – the fact is, they suck.
Air is always drawn towards areas of lower air pressure. Natural ventilation makes use of outside air movement and pressure differences to cool and ventilate a house.
To draw the best breeze through your home, position larger openings on the more sheltered low-pressure side of the house and smaller openings on the high-pressure side facing the wind.
Openings near the centre of the high-pressure zone are more effective because pressure is highest near the centre of the windward wall and diminishes toward the edges as the wind finds other ways to move around the building.
Try to position your windows and doors to direct the airflow to the areas where you hang out the most, like family rooms, lounges and kids’ bedrooms.
Make sure there are windows or doors on at least two sides of rooms. The idea is to position them so that the air is sucked in one opening and pushed out another one directly opposite, like a vacuum effect.
To enhance the effect, a good tip is to open your window where the breeze is coming in a little less, and have the window on the opposite wall a little more open.
If your rooms aren’t built this way, don’t worry, the air will still find a way out, even if the opening is at 90 degrees from the inlet.
Because breezes come from lots of different directions, and can be deflected and diverted, the orientation of an opening to the breeze is less important than the actual design of windows and doors that direct it. The size and the style of windows in particular will affect the amount of air moved and how it is directed or deflected.
Hot air rises, so cross ventilation works best when the window that is exposed to the wind is open at the bottom, and the window on the opposite side of the room is open at the top. The warm stale air gathering under your ceiling is pushed out and replaced with cooler fresh air from outside. Wideline double hung windows are perfect for the job.
Even if you only have one window in your room, you can open both the bottom and the top sashes of a double hung window. The sashes move smoothly, one in front of the other, allowing cool air to stream in through the lower opening, while the hot air zips out the top. They can be adjusted according to the direction of the wind, so you always have cross ventilation in your home.
Classic Wideline casement windows have hinged frames that open inwards and outwards, just like a door. This makes them brilliant at catching and deflecting breezes from any angle. You get maximum air when they’re fully opened, and you can stop them wherever you like to control the air-flow.
Streamlined Wideline sliding windows and doors have sashes that glide past each other horizontally allowing for the largest of openings and max airflow. Because they don’t open outwards, you can add insect screens, and they won’t obstruct outside spaces like patios or walkways when they’re open.
Want cool? You’ll love louvres. They’re made from a series of rectangular glass panels which pivot open to let the air in. Adjusting the angle of the slats controls the speed and the direction of the breeze.
Frosted Wideline louvres above and either side of an entrance door make a real statement, and direct breezes down your hallway while maintaining privacy and security.
You can even use louvres as internal walls to visually connect rooms and open up wind-flow paths throughout your house.
Motorised Louvres used as Clerestory windows encourages Convective ventilation and makes it super easy to direct the flow of hot air high above head height.
If your house is built into a slope or has different floor-levels, you can open windows in the lower and the upper floors to take advantage of the stack effect and reduce temperatures inside.
Called Convective ventilation, it uses temperature differences to move air. Even when there is no breeze, lighter warm air rises up to escape through high openings like Louvre Clerestory windows, drawing in cooler air from lower down as it makes its way up.
It’s clear that natural, passive cooling can keep your home comfortable throughout summer, fill it with fresh, healthy air and reduce your energy costs by bucketloads.
Done correctly it’s simple, cheap and effective, but putting the right style of Windows and Doors in the right place makes all the difference.