How to design your very own cool Summer oasis?
As Autumn comes around and Summer comes to an end, thankfully, we are also seeing the end to the occasionally unbearable heat that comes with the season. As the thermostat rises, we are reminded of how poorly some of the houses we live in cope with the extreme heat of our Summer. Poor design and poor construction methods are the two culprits responsible for this discomfort we are put through. Quite often, we are left in a state where we have no option but to set the air-conditioner to the max, or escape the house completely to seek solace from the heat.
Overall the cooling of your home in Summer can be broken down into two categories, the first being the design and the second being the construction. Both of which are your designer’s responsibility to not only design correctly, but to then document and specify the correct materials and construction.
Starting with the design aspect of creating a cool home, below are the items which must be considered during the design phase.
It all starts right at the very beginning of the entire process when selecting your block. However, for those of you choosing to work with an existing house this will obviously be your starting point.
We have discussed orientation in detail before and if you wish to read about it in further detail you can here. Ideally, you want an elongated north face for your block of land and house for Winter heating. This also plays a role in keeping your house cool in the Summer. The north facing sun is much simpler to shade compared to the morning sun rising east and the afternoon sun setting west which gets under shading devices, therefore, shading these become a lot more difficult. Being able to shade the sun from entering your home will assist in keeping the temperature within your home down.
In Summer the cool sea breezes provide you with natural air conditioning to flush out hot air and cool your home. In Perth, the south-west afternoon breeze (commonly referred to as the freo doctor) enters the home via windows located on the south and west orientation and out the windows located on the opposite face of the building.
The breezes can be further captured through the use of correctly placed stepped walls in the building along with correctly placed windows and/or with the use of correctly designed and positioned wing walls. Wing walls work similarly to stepped walls in the building. Both options work by providing a larger surface area to capture the breeze and then directing it towards the designated window opening.
Cooling breezes can be further enhanced by creating 'cool zones' at the location where the cooling breeze is to be captured. These breezes then pass through this cool zone, further cooling the air before it enters the house. A cool zone can be a well shaded, dark cool space located at the cooling breeze entrance point outside of the home. Bodies of water and ponds can also assist in further cooling these breezes.
Open floor plan
An open floor plan can be utilised to enhance the flow of the cooling breezes once it has entered the house. For a cooling breeze to work efficiently, it requires little or no barriers in its path between entering the house and exiting the house. An open plan floor plan provides this perfectly as the breezes can enter on the south and west facing side and then pass through this open area without any interruptions, therefore flushing the hot air out through openings on the opposite side of the house.
Some types of windows will perform better in certain locations compared to others. A louvre window works well for smaller windows, as it provides a 100% openable space in comparison to a sliding window, whereby only 50% of the window is openable.
Window heights can also play a big role in the natural ventilation of your home. Low level windows can be utilised to suck in the cooler air, with high level windows pushing out the trapped internal hot air as it rises. This again creates a natural and free air-conditioning system. This particular design method relies on the air movement internally as the less dense hot air rises, rather than relying on capturing external breezes, however these two can be combined to work together.
Before you look at incorporating window glazing into the construction of your home, you want to make sure that your shading is correct. There is little point spending any additional money on improved glazing if your basic design principles have not been considered. Shading your house greatly reduces the inside summer temperature, improving the comfort levels without any auxiliary cooling.
These window and wall shadings are crucial in reducing unwanted heat gain. Effective shading such as window awnings or shutters, eaves, pergolas and even plantings can block up to 90% of the summer heat. Unprotected glass is the greatest source of heat gain to a house. It is crucial shading is correctly designed so it blocks out all summer sun whilst still allowing the winter sun to penetrate deeply into the home.
Thermal mass is the ability of a material to absorb and store heat energy. High density materials such as concrete, bricks, stone and even tiles require a large amount of energy to change their overall temperature. Therefore, they are fantastic materials to use for your home, when utilised in the right location. The key being the right location. Badly placed thermal mass can worsen the extremes of the climate by storing and radiating heat in Summer. Good thermal design will moderate the indoor air temperature throughout all seasons of the year. In Summer, the thermal mass should be shaded from direct sunlight. This allows the thermal mass to absorb internal energy/heat from the inside the house during the day. The cool night breeze then passes over the thermal mass, drawing out any day time stored energy/heat which then, in return, cools the overall internal temperature for the day to come.
Glazing brings in light and fresh air, however, along with this comes the summer heat. Up to 87% of the homes heat is gained through glazing. With today’s technologies, there are a wide variety of different glazing types, with each performing slightly differently. This provides you with the opportunity to use the correct glazing type for the windows specific job.
Along with correct shading, insulation will help prevent unwanted heat from entering the house. Insulation acts as a barrier to heat flow, preventing not only the hot outside air in summer entering into the house, but also the cooler internal air escaping.
Air leakage will allow the hot outside air in summer an entrance point into the house, but also the cooler internal air an escape point. If air leakage is minimised, ventilation through desired openings can ensure the solar passive principles incorporated into the design work to their maximum ability to cool your home.
So with some small upfront planning and good design, you can have your very own cool Summer oasis in your own home.