As the temperatures skyrocket during the summer, so does the demand for home cooling—often costly to both the hip pocket and your carbon footprint. Let's look at a few ways you can increase thermal performance and create a comfortable and cost-effective passively cooled home.
Large glass windows can be a major source of unwanted heat loss during the cooler months and heat gain in summer. The type of glazing that is right for your home will depend on the climate, orientation and layout of your home. For example, a large western-facing window in the main living area will receive the concentrated afternoon sun and drastically diminish the thermal performance of your home.
In this situation, when selecting windows and glazing for a new or renovated home, you should consider installing a window with a highly-insulated frame material and a glass treatment suitable to your environment. Laminated, toned and low emissivity glass are excellent ways to reduce solar heat gain. Insulated glass units combine more than one layer of glass and sealed cavities to produce a window with excellent thermal performance.
If you're looking to increase the passive cooling properties of your windows without replacing the frame and glass entirely, secondary glazing allows retrofitting of an existing window by inserting a second panel of glass to act as a double glazed unit. Alternately, adhesive window films are the most cost-effective and quick method of preventing heat gain and loss by absorbing or reflecting solar radiation.
Minimising the direct sunlight that hits your home's exterior is the ultimate method of passive cooling. With a little landscaping forethought and the addition of a few fixed shading devices, you can decrease the glare and solar heat gain of your home drastically.
Easterly or westerly-facing homes benefit greatly from the addition of wide pergolas designed to shade openings and walls, particularly when combined with shade cloth or thick, quick-growing vines such as grapes, honeysuckle and jasmine. A north-facing wall can be thermally improved with correctly-designed eaves or window shading such as awnings or louvres. A southerly-facing façade can be thermally protected with careful planting of shade-providing trees, bushes and creepers.
One of the easiest and cheapest ways to passively cool your home involves preventing excessive air leakage in your home by ensuring that all gaps are adequately sealed. Eliminating leakage of cooled air will save your cooling costs, and increase home comfort year round.
Some of the most common sources of air leakage are shrunken floorboards, poorly sealed windows, doors, vents and exhaust fans, as well as gaps around wall-fitted appliances such as heaters, air conditioners and even power outlets.
Many home handypersons can locate and seal small gaps in an afternoon, with a little help from a multipurpose flexible gap filling agent and a few cost-effective draft-proofing products. Ensure that there is still adequate ventilation in your home, however, as air tightness can lead to increased humidity and a build up of toxic gasses and allergens.
A Holistic Approach
If you are serious about reducing your energy consumption by passively cooling your home, you may need to consider retrofitting your home with innovative passive design features such as a reflective roof, increased overhangs or a higher quality insulation product in your roof cavity.
If you are considering building a home with passive cooling as a guiding design principle, it is advised that you speak to a home builder like Seapointe Homes for detailed, professional advice. As the planning and design of a passive home is a complex calculation of location, orientation and seasonal changes, it is important to have your property assessed to maximise the thermal performance and minimise energy consumption of your new home.
With passive cooling solutions for all climates and budgets, you can improve the thermal performance of your home and prevent a huge energy bill this summer without compromising your comfort.