Summer — a great excuse to hit the beach or blast the air conditioning. With the sweltering heat creeping closer every day, blasting the A/C might seem like the only reasonable option to keep cool. However, with the cost of electricity always going up & up, the thought of your power bill might make you rethink grabbing the remote as your first option.
At Anderson Energy Efficiency, we’ve assessed thousands of houses & units, so we’re quite skilled at knowing how & why some buildings can get so hot while others seem pleasant all year around. So we’ve put together some helpful tips to be energy efficient while keeping your home cool in summer!
1. Throw Out Some External Shade
The first solution to overheating is to keep the summer heat out. Ideally, you want to be controlling how much sunlight is heating your home, which is much easier said than done. The first (and easiest!) step is minimising the amount of sunlight that hits any glass windows or doors. One way this can be done is by installing external shade in the form of fins, blades, lattice, awnings, outdoor blinds or external window decals. Try hanging tightly woven screens or bamboo shades outside the windows during the summer. Even large potted plants & vegetation can provide an aesthetic measure of external shade. Anything that minimises how much sun goes through your glazing!
2. Block the Summer Sun
By applying a strong solar-tint film to your glass, you can control the amount of solar heat coming through the glass. Choosing the right tinted film for your glass (such as a heavy tint with a Solar Hear Gain Co-efficient less than 0.30) could reduce a room’s cooling bill by 30% to 50%, depending on which direction the glass is facing. When deciding which windows are more important, remember that East & West facing glass lets more heat inside than North & South facing glazing. If tinted film isn’t an option for you (for instance, if you’re renting), you can try other methods of blocking out the sun.
3. Cover Your Windows
Even on a low budget there are still some super cheap options available for extremely hot windows – for instance, taping a layer of bubble-wrap to a window isn’t the prettiest but it’s a cheap way to make a window perform as if it was double glazed, and placing a car windshield reflector on the inside of your window will reflect most of the sun’s rays. And while either of those options certainly aren’t as pretty as window tint, they both have the added bonus of acting as partial sound absorbers too!
4. Consider Your Curtains
Another way to affordably reduce solar infiltration is by adding internal block-out blinds or curtains. These are special blinds with a white or reflective outer surface that bounces back unwanted radiant heat. Heavier blinds or generous drapes have a higher R-value, meaning they’re better insulators. The closer the curtains are to the window the better, since any gap between the glass & curtains will hold hot air that slowly leaks through the curtains. And don’t forget adding a pelmet cover above the heavy drapes – pelmets can double or even triple a window’s effective R-value. Adding blinds or curtains is the least effective method of heat control, but it’s also one of the least expensive options.
5. Make the Most of the Cool Summer Breezes.
In a modern house it’s often said it’s best to close up during the heat of the day. From late afternoon onwards, throw open the windows; overnight temperatures are lower outside than inside. However, in an older Queenslander with poor insulation, sealing and ventilation can work against you, trapping the hot air inside the house. It’s a good idea to invest in an indoor-outdoor temperature device so you know when outside has cooled down and you can open up for some fresh air.
6. Clean your Fly Screens
On the topic of airflow, when was the last time your fly screens were cleaned? It’s surprising how much dust & dirt gets trapped in that fine mesh. A simple scrub down can almost double the airflow through your house, so definitely make it part of your spring cleaning routine!
7. Service Your Air Conditioner
Sometimes it’s just too hot, and you’ll end up turning on the air conditioner. But before you do, stop for a moment and think – when was the last time you had yours serviced? Like any machine, it needs to be serviced regularly and its filters cleaned in order to get the most out of it! For tropical climates, most of the ‘heat’ you feel is caused by the high humidity, so setting your air Ccnditioner to dehumidify can also make your room feel much cooler.
8. Fans (ceiling & portable)
There are a few things you can do to make the air temperature inside your home feel lower through what we call natural or mechanical ventilation. This sounds a little technical, but it’s as simple as replacing a light fitting with a ceiling fan. This is cost-effective and provides a breeze when the air outside your home is uncomfortable or restricted because of poor ventilation. If you use a ceiling fan or pedestal fans at the same time as your air conditioner, you can normally get away with setting your A/C a few degrees higher – and every degree higher you set, is another 10% to 15% less electricity it’ll use.
Just remember that fans only work when the room is occupied, as they’re designed to work on people, not on the building, or those savings might go to waste!
9. Make a “Cool Room”
It sounds pretty simple, but by closing doors and only cooling the room you’re using, you’re not wasting energy cooling the entire space. Using draft-stoppers on doors & sealing up window-leaks will stop that nice cool air from sneaking out. The room will also cool faster! Additionally, if you have notorious ‘hot rooms’, close the doors to these areas, to stop them heating up the rest of the house.
10. Extractor Fans
If you can’t stop the heat getting in, get it out! Exhausting the air through a roof ventilation fan can make a difference. There are many types of roof ventilators, and some are solar powered making them free to run. Be aware that “whirlybird” style ventilators provide only limited benefit because of their size and slow speed; a decent roof ventilator needs a fan inside it to provide maximum cooling potential.
11. External Upgrades
If living in an overheating (or oven-heating) home has become a constant struggle, it might be worth the effort to run the numbers on re-painting your home & roof to a lighter colour with additional heat protection.
These two things are the first line of defence in protecting your home against the scorching heat of the sun. They should be reflecting and releasing the sun’s energy rather than storing and absorbing it and pushing it into your home. That being said, these options can be expensive, so only consider this when they’re due for a replacement or upgrade already, or if the heat creates real problems in your household.
12. Invest in Insulation
Insulation can make a big difference, especially if you currently don’t have any. Adding additional insulation does normally help, but it has diminishing returns on making your home cool. When outside is hot (even at night) then the thermal resistance, or R-value of all building external surfaces controls the amount of unwanted heat entering your home.
How much insulation is enough? What type of insulation works best? There are a few rules of thumb you can use as guesstimates, but this really is something that needs to be calculated for your actual building. The calculation is an Energy Efficiency Assessment, which estimates the amount of overheating that needs to be removed to stay comfortable.
Keeping cool without losing your cool
Remember that some “solar treatments” designed to cool your home in summer may also make the home cooler in winter, resulting in more heating required. You’ll have to think about whether or not this will happen with the changes you’re making, and if this is a fair trade off. But keep in mind that it’s much easier to add another layer of clothing in winter than to take off another layer of clothing in summer.
The examples above show that modifications can be made to make hot homes more comfortable to live in. Heat does not always have to be reduced through active means like air-conditioning. Modifications to windows or home surrounds means that less heat will enter your home. When considering modifications, keep in mind the cost vs performance of different solutions. Preventative measures can save the environment & your money by making your home more energy efficient!