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Should I Install a Roof Vent?

Choosing among whirly birds, mains powered vents, and solar powered vents.

Ventilation allows air to flow within a space in your house through a system of intake and exhaust. By installing proper ventilation, you will be able to reduce your energy costs, regulate indoor temperature, and extend the life of your roof.

How does roof ventilation work?

Roof ventilation allows air to flow through the ceiling space to prevent overheating and excessive moisture.

There are two ways to create air flow within your roof space:

  1. Mechanical – requires a power source

  2. Natural – driven by the movement of air

Ever heard of the stack effect? This occurs when hot air rises and creates high pressure in top of a building. To allow hot air to escape, you must find a way for cool, low-pressure air to get in. The cool air that enters is called intake while hot air that escapes is called exhaust.

Meanwhile, wind effect occurs when the wind blows against the outside of a roof and generates the natural flow of air.

Benefits of installing a roof vent

In essence, proper ventilation allows the fresh air in and the stale air out. A well-ventilated attic will have bottom roof vents at the soffits or eaves (intake), and top roof vents at the peak or ridge (exhaust). With optimal air circulation, your attic space will have uniform temperature and humidity regardless of the season.

In order for roof ventilation to work effectively, there should be a balance between intake and exhaust.

Balanced ventilation means that the intake and exhaust allow the same amount of airflow as natural air pressure creates a push-pull effect around your roof. Without proper intake, air will only circulate across the top and leave stagnant air at the bottom. Without proper exhaust, hot air won't be able to escape.

It would help to have vents on both sides of the attic – similar to having windows on both sides of the house to allow the breeze to circulate.

What can a balanced ventilation do for you?

· Improve air quality

As mentioned, roof vents replace stale air with fresh air which can help improve air quality in domestic settings, particularly in small spaces such as kitchens and laundries. In commercial and industrial environments, roof vents are even more beneficial as these spaces often contain fumes, toxic gases, grease-laden air, and corrosive vapours. Proper ventilation can remove all these elements and replace dirty air with clean air.

· Keep cooling costs down

During a 90° summer day in Australia, hot air gets trapped in ceiling spaces with temperatures reaching 140° or higher. Without an exit, this hot air stays there. This increases the indoor temperature below, which forces your air conditioning, fans, and other cooling appliances to work harder.

Roof vents can help push hot air out and cool down the ceiling space in homes, warehouses, factories, and other structures. By taking the load off the air conditioning, roof vents contribute to lowering your cooling costs.

· Prevent cold-weather condensation

Winter weather is a much tougher challenge for attics. When warm indoor air rises to a cold roof, it condenses into moisture. This can cause the roof deck to buckle, swell, and rot over time. Condensation also attracts mould and mildew, which can have a negative impact on indoor air quality and trigger allergies.

· Eco-friendly and energy-efficient

Whirly bird roof vents harness the power of the wind to remove stale indoor air and replace it with fresh outdoor air. This makes them eco-friendly and energy-efficient.

· Durable and long-lasting

Top-quality roof vents usually come with 10- to 15-year warranties. In some cases, they last even longer. Whirly bird roof vents are made of durable construction material, with some models built with fireproof mesh for homes that are located in bushfire-prone areas.

· Easy to install

Roof vents are typically lightweight, so they are easy to transport and install for roof specialists. Here at Sydney Roof and Building Supplies, we offer flexible installation solutions to meet your exact ventilation needs.

· Zero maintenance

Roof vents are designed to withstand harsh weather conditions and require little to no maintenance. Once installed, they work well with minimal human intervention.

Do you need a roof vent?

Modern Australian houses are built with roof cavities with plenty of insulation to keep them separate from the air-conditioned interior below. However, if your home does not have such an airtight ceiling, you can expect warm, moist air to find its way up to the roof.

Do you have a metal roof? Is your roof colour dark? These are likely to absorb more heat and release hot air into the rest of the house. A roof vent is exactly what you need to keep your roof cavity from getting too hot.

Types of roof ventilation

If your home is poorly ventilated, you have many roof vent choices to choose from.

1. Whirly birds

Conventional ventilation solutions can come with significant installation costs. They also require a power source, which means you are going to incur operational expenses. On the other hand, wind-driven roof vents – more popularly known as whirly birds – are not only cheaper but more far more effective in pushing air out of your roof.

2. Mains-powered roof vents

Mains-powered roof vents are significantly more costly than whirly birds and require a power source in the roof space. You will have to install a power outlet in the roof if you currently don’t have one.

3. Solar-powered roof vents

Solar-powered roof vents are almost as pricey as mains-powered roof fans upon installation, but they do not have operational costs as they rely on the sun for power.

Things to consider when installing roof vents

If you are considering installing roof vents, here are four things you have to consider before making a purchase:

  • Number of units – what do you need and how much do they each cost?

  • Ease of installation – can you do it yourself or do you have to pay someone else to install them?

  • Quality of installation – make sure they are watertight for your peace of mind during wet weather.

Generally, whirly birds are easy to install and most are suitable for installation on Australian roofs. Some mains-powered roof vents and solar-powered roof vents come with a variety of flashings that are designed for American roofs, this makes them difficult and time-consuming to install on tin and tile roofs in Australia.

If you aren’t sure what type of ventilation will fit your roof, give us a call at 02-8090-3483. Our roof specialists in Sydney NSW can tell you exactly what to look based on your location, roof type, and whether your roof is fully conditioned or thermally isolated.

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