There are so many roof ventilators on the market to choose from – turbine ventilators, ridge ventilators, louver vents, gable vents, static ventilators then you have roof ventilation fans and solar fans – so how do you choose?
You will need ventilators that work as a system, to allow the ambient air (the air that surrounds) to enter the roofspace to flow through the roofspace and eventually exhaust from the roofspace. To cool the home in summer and dry the roofspace from condensation problems in winter – the secret ingredients for any roof ventilator to succeed in doing this task is the harnessing of the principles of fluid dynamics.
The Principles Of Fluid Dynamics In Relation To Roofspace Ventilators In Short Detail -
Convection (sometimes referred to as the stack effect) to put it in laymans terms hot air rising cold air falling – Newton’s Law of Cooling (basic physics).
The Venturi Effect – causing air to pass through a small area and increasing the airs velocity, the average flow speed of air doubles through a constriction.
Airflow – natural movement of air currents, atmospheric flow, wind. Free air flow; air currents picked up across the plane of the roof passing though a small area increases the air’s velocity.
Fluid Dynamics Explained in Brief - In physics, fluid dynamics deals with fluid flow – the natural science of fluids (gases and liquids) in motion. It has several sub-disciplines itself, including aero dynamics the study of air and gases in motion, such as velocity, density, pressure and temperature functions of space and time.
So How Do We Harness The Principles Of Fluid Dynamics And Feed Them Through The Roofspace?
Eaves Vents - Most roof ventilators incorporate eaves vents to induce ambient air into the roofspace – without eaves vents they would just be a stand alone ventilator and not part of a system.
Whilst eaves vents are a reasonable way to induce air into the roofspace, eaves vents do have their draw backs – quite often the roofspace will be blocked from the eaves due to a barrier being formed by ceiling insulation – unless a gap in the insulation has been formed to allow air to enter the roofspace and quite often this is generally not the case. Then there is the problem of people fixing roof ventilators in the roof and not even fixing eaves vents at all. This is usually normal practice.
Just have a look next time you see a whirlybird spinning around check the eaves and see if you can see any eaves vents, you may but it is doubtful you will.
Roof Ventilation Is Quite Often Misunderstood By Sales People Selling Roof Ventilators They Seem To Have Little Comprehension Of The Science Involved.
What Can You Do With A Home That Has No Eaves – How do you induce the ambient temperature into the roofspace For The Ventilators That Depend On Eaves Vents.
Some Believe Ceiling Vents Will Do The Trick – Well This Is Simply Not True.
The air from inside the home will not be at ambient temperature – although this air will rise due to convection it is simply inadequate to cause an airflow throughout the roofspace. For a roofspace to ventilate – the air inside the roofspace needs to equalize with the outside air the ambient air.
The Use Of Ceiling Vents And Sick Building Syndrome.
Another serious problem can arise with ceiling vents being open to the roofspace – ceiling vents will allow allergens to enter the home from the roofspace – dusts from the breaking down of building materials, the fibres from fiberglass insulation ceiling bats as well as probable mould spores from fungi growth. These all increase the probability and/or further exacerbate the ailments of asthma, coughing and wheezing, bronchitis and all types of lung and fungal infections with elevated rises of throat irritation, skin irritation and eye irritations.
Just do this simple test – take the bulbs out of your bathroom tastic and see what has collected around them, this is just a small example of what enters the home through ceiling vents.
Mould spores are a serious threat to our health and one of the most dangerous problems of sick building syndrome they are airborne and so minute they cannot be seen by the naked eye.
So if you are at all going to use ceiling vents don’t even consider them as an inducement for roof ventilation – make sure that the ceiling vents are ducted through the roof to the outside atmosphere.
Some Say The Bigger The Better.
Bigger is not always better to give you a scenario – a Cadillac is twice as big as a Volkswagen and takes twice as much fuel in its tank – however the small Volkswagen will go just as far or most likely much further than the Cadillac on its small tank of petrol.
Sheer size alone is not a competitive advantage over better designed products, quality comes in any size more performance more reliability will beat bigger every time.
Turbine Ventilators – Roof ventilators with moving parts these will all wear out at some time and need replacements it just depends on what you pay for them as to how long they will last.
Roof Fans – These also have moving parts and also need electricity to run them, they will eventually need repair or replacement as well as the cost of the labour in the maintenance and/or replacement. Do they work well? Providing you have enough of them for the size of your roof and have at least 4 eaves vents for each unit to allow the ambient air to circulate the roofspace.
Solar Fans When The Sun Goes Down They Go Down – The same issues with grid electric fans with moving parts becomes an issue, although you have the advantage of when the sun is shining they are not costing you anything to run however there is the other side of the coin – when there is no sun there is no fan. One of the major advantages of having roof ventilation is for the condensation problems of winter – these condensation problems are mostly caused during the periods of nighttime when the heat from the inside of the home rises to come in contact with the underside of the roof covering – (the tiles or colorbond) – this is called the Dew Point, this is when the moist heat becomes condensation it could be raining in your roof if you have no ventilation. Solar fans may be useful in the height of summer however – when the sun goes down so do solar fans – so not a good option for winter.
Aerodynamics – Most roof ventilators rise substantially above the roofline, leaving them vulnerable to the elements without any thought to aerodynamics.
What Characteristics Are Needed In Roof Ventilators To Give You The Best And Longest Lasting Effective Results.
- A roof ventilator should be part of a system that works well within itself, having inlets and outlets within the roof covering – giving the best results for the cooling of the home in summer and drying of the roofspace from condensation problems in winter.
- The ventilation system should harness all the principles of fluid dynamics to enable the system to work very efficiently to allow the ambient temperature to flow through the roofspace.
- A system that has no moving parts, that never needs repair or replacement that will give you both long lasting and effective results.
- A ventilator that is aerodynamically designed to harness the principles of fluid dynamics as well as allow mother nature to thow at it all she has – cyclones storm cells all of the extremes, being ember proof to Bal 29 for bushfire zones.
- There Are 4 Seasons In A Year So You Need Ventilators That Work For Your Best Interests All Year Round not just for the height of summer – condensation is one of the worst problems in roofspaces today – causing damage to the roofing materials, breaking down the R value of the ceiling insulation as well as a large contributor to Sick Building Syndrome.
What Is Condensation – Condensation comes from the moisture in the air – condensation generally occurs when warm air rises, cools and loses its capacity to hold water vapour.
The worst states for condensation problems are Tasmania, Victoria, Southern NSW however we are finding that condensation is on the increase in the colder climates in most other states.
So Therefore Consider The Facts you need ventilators that are for all seasons – for all that mother nature has to throw at them – ventilators that are systems within themselves – ventilators that use all the principles of fluid dynamics – ventilators that are aerodynamically designed – roof ventilators that are proven to work all year round that never need to be repaired or replaced.
Universal Tile Ventilators for tiled roofs and Smoothline Ventilators for corrugated colorbond roofs tick all the boxes for very effective roofspace ventilation.
ANYTHING ELSE IS A COMPROMISE.
PREPARE TO BE AMAZED.