Super Therm 95% Solar Heat Block from the Australian Sun

The Super Cool Roof Guide

We know that sitting in the hot sun is more pleasant in a white T-shirt than a black one. The same can be said for buildings – more and more scientific research is revealing how a white roofs are good for the planet, reducing the heat build-up in cities and in our homes. Fortunately, no aesthetic sacrifices are necessary if you’re opting for a white roof. A home with a white roof can be the envy of the neighbourhood.

30 Cool Roof Facts

Without doubt the future need for Cool Roofs as part of our urban landscape will become necessary and mandatory. As global temperatures rise, cool roof technology will become a frontline defences to rising solar heat, heat waves, increasing energy costs, rising carbon emissions and public and personal safety. Roofs are not always considered when looking at ways to improve building energy efficiency however, ‘cool roofs’ do more than simply protect a building’s occupants from the harsh environment.

For thousands of years the architecture of many ancient civilizations around the world has long recognized the benefits of light‐coloured external surfaces on buildings to improve the internal comfort levels in hot environments. The problem of global warming has renewed interest in products with low solar surface absorptance both in Asia, North America and Europe. There is a growing understanding that these products can provide a number of benefits including a reduction in the cooling and energy demand in summer, better and safer well being of the community, increased heat reflection in urban areas, reduction in the heat island effect and a reduction in greenhouse gas emissions.

Cool surfaces deliver benefits worth 12x their cost

Dian Grueneich, Director, Global Cool Cities Alliance

There are a range of options for the application of Cool Roofs, however this Super Cool Roof Guide is focused on Super Therm® Solar Heat Block Coating and its outstanding worldwide success to mitigate heat into buildings, vehicles, transportation, containers and more. Super Therm® goes a long way to assisting in the proven reduction of energy use and therefore the Urban Heat Island effect. With one of the world’s highest TSR ratings of 96.1, Super Therm® stands out from the crowd of heat reflective paints as a true heat block coating.

A cool roof is one that strongly reflects sunlight and minimises the amount of heat generated when the sun heats its surface. It also cools itself by emitting radiation to its surroundings when the sun sets or weather changes. The technology means roofs should stay cooler, and reduce the amount of heat conducted to the building it shelters, contributing to more stabilised internal temperatures (Australian Architecture and Design). 

A Super Therm® cool roof does much more:

  • Reducing the heat load into a building reducing CO2 emissions
  • Reduces energy use and consumed
  • Reduces the urban heat island effect
  • Protects the roof as an asset from thermal shock
  • Adds fire protection
  • Mould and mildew reduced
  • Sound reduction

The Cool Roof conversation should be unnecessarily complicated. If you want to know how complicated the conversation is regarding, read this article by Cameron Jewell on Cool roofs versus dark roofs: special report. On its website Monier says: “Light coloured roof tiles keep cooler than darker coloured roof tiles and this cooler temperature can mean reduced energy costs for cooling a home or building.” A spokeswoman for Monier in the article said that the company had “a fantastic range” of light ­coloured tiles, however customer preference was heavily skewed towards dark tiles. In the same article the spokeswoman also unfortunately said that building scientists who were part of parent company CSR said that colour did not make a significant difference to thermal performance of a house because roof insulation formed a thermal barrier. This gives evidence of the mis-messaging the customers receive regarding roof colours, thermal protection and benefits of Cool Roofs.

White roofs help cool the planet; dark roofs warm the planet

Mona Quinn, Houzz

In a recent study Cooling Darwin: UNSW plan to fight climate change, Scientia Professor Mat Santamouris outlined urban overheating threatens the lives of people in Darwin, but researchers from UNSW’s Faculty of Built Environment have calculated how many lives could be saved by changing the city. “We found that mortality increased by 5% for every 1°C increase in daily maximum temperature.” Urban overheating has a serious impact on human health and the economy because it increases the concentration of urban pollutants, affects urban air quality, increases energy consumption for cooling purposes and raises carbon dioxide emissions. He said the annual cooling load saving from greenery is an estimated 88.4GWh, while the application of cool roofs and pavements is 214GWh – UNSW NewsroomFull Report pdf.

Darwin City Final Report states: The mitigation potential of reflective roofs depends on several parameters like the local climate and in particular the solar radiation intensity, the ambient temperature and humidity, wind speed and cloud cover, optical parameters like the reflectivity of the roof to solar radiation and the emissivity factor, thermal parameters like the thermal capacity and the U-value of the roof, and technical parameters defining the ageing process of the reflective roofs – Page 60 – Full Report pdf.

The U-value measures how effective a material is an insulator and must be a consideration for standardisation of heat reflective paints and heat block coatings to part of the overall consideration of the thermal efficiency of all products. Understanding the Heat Load of a cool roof is critical and gives consumers the full picture of thermal benefits a product. Quite often there is just a focus on the SRI (Solar Reflective Index) which does not take into consideration the heat load penetrating into the substrate and transferring into the building therefore this is not giving the full and complete picture.

According to Architecture and Design, a whole range of design elements fall under the umbrella term of “cool roofs”. Essentially, a cool roof is one that reflects the suns heat and emits absorbed radiation back into the atmosphere at a higher rate than standard materials, literally staying cooler than a standard roof. This reduces the amount of heat transferred into the building below, keeping it at a more constant temperature however without a standard such as U-value no one is able to conclusively state what their product actually achieves in thermal efficiency. Similar to the R-value, the U-value aims to measure thermal transmittance into a building.

Cool roofs are reflective surfaces designed to reflect more solar radiation and absorb less heat than a standard roof – Victorian Energy Saver Program. ‘Cool roofs’ use roofing materials with high solar reflectance and thermal emittance, reducing the heat absorbed from the sun and increasing the heat radiated out to the sky. Cool roof technology reduces the amount of heat transmitted into buildings on hot days, and thus the amount of air-conditioning required for cooling. Their widespread use across a neighbourhood or precinct can mitigate the urban heat island effect (CRC).

There are a number of ways to use roofs to decrease the environmental toll of our built environment and to begin to use urban infrastructure as an agent of adaptation and environmental services. Installing white roofs, cool roofs, vegetated roofs, solar hot water, or photovoltaic panels can all be effective ways to improve the energy and environmental performance of roofs.

By reducing the fraction of incident sunlight that is converted to heat by the roof, cool roofs can help cool buildings, cities and the planet. The most popular type of cool roof is a bright white roof, cool coloured roofing materials have become available for steep-sloped roofs (mostly residential). Compared to white roofs, cool coloured roofs are less solar reflective and a bit more expensive.

Cool roofs are an order of magnitude cheaper to install and pay back faster than vegetated roofs. Super Therm® as an example offers 95% solar heat block amongst a range of other benefits that reduces electricity use in air-conditioned buildings, increase thermal comfort in unconditioned buildings, reduce the urban heat island effect, and by saving energy helps mitigate global climate change.

It started with an article on a study out of Berkeley Lab in California, which concluded that white roofs outperformed black roofs economically as well as environmentally. It called for the phasing out of dark roofs in hot climates, especially those prone to heatwaves. This would save energy costs, protect against the urban heat island effect and tackle climate change – The Fifth Estate

When it comes to the solar passive design of your new home, a dark-coloured, high solar absorptance roof is not a good idea, as it will make it more difficult to achieve a thermally comfortable internal environment during summer. Even if you intend on installing air-conditioning, a high solar absorptance roof will mean the air-conditioning will have to work harder to cool down your home, meaning higher electricity costs and increased carbon emissions – The Fifth Estate

“Rapid deployment of cool materials represents one of the largest and most cost-effective opportunities we have to counter global warming, improve health and strengthen security.” U.S. Secretary of Energy, Steven Chu – (Global Cool Cities Alliance)

In an insights brochure, Boral stated it was “seeing a move towards lighter colours that blend with the natural environment” (source). Dr Chris Reardon, principal author of the Your Home guide said “Research shows that light coloured roof tiles can lower the air temperature in the roof space by up to nine degrees compared to dark tiles.”

Dr Reardon warned that when designing houses, instead of taking into account current climates it would be prudent to look at projected temperatures over the 50-80 year lifetime of a house, with CSIRO research predicting temperatures up to 4°C warmer on average by 2100. (source)

Need for the future change

  • Legislation that prevents dark roofs for the future
  • Mandatory for public buildings for cool roofs
  • Education for property developers
  • Mitigation based on best technologies and plans – not myths
  • Reduce cultural norms for dark roofs
  • Industrial areas and large span roofing helps improve working environments
  • Necessity will drive cultural change
  • Cost of power will drive change
  • Government to provide stimulus for cool roof technology – reduces pressure on energy security
  • Put cool roof technology in the building codes
  • Government lead by example put on your buildings; show its real
  • Ensure all tenders cover efforts respondents will take to reduce heat

30 Cool Roof Facts

Cool roofs are designed to be used in summer and warmer environments to reduce solar thermal loads through roofs and walls. When surfaces are designed to reduce or block heat transfer and heat load, that energy isn't transferred into the building and absorbed by the bulk insulation which keeps you cool. Super Therm has been tested to block 96.1% of total solar heat allowing just 0.070 W/m2/K of heat transfer...compared with Zincalume that allows 40 W/m2/K.

The reduction in the use of energy naturally equates to a reduction in energy power consumption and power bills. Con Edison research from New York stated a 6° reduction in the thermostat produces a 39% reduction in utility costs. Therefore a KW savings = Actual Dollar Savings. Cool roof coatings like Super Therm have proven energy savings benefits that convert to less power consumption, therefore less mechanical running costs.

A Cool roof reduces the need for mechanical air conditioning demands in buildings. Without the pressure of reducing temperatures due to excessive heat, the need for keep the building cool is reduced. There are just over 1 billion single-room air conditioning units in the world right now – about one for every seven people on earth. Numerous reports have projected that by 2050 there are likely to be more than 4.5 billion, making them as ubiquitous as the mobile phone is today. The IEA projects that as the rest of the world reaches similar levels, air conditioning will use about 13% of all electricity worldwide, and produce 2 billion tonnes of CO2 a year – about the same amount as India, the world’s third-largest emitter, produces today (Buranyi, 2019). More CO2 means further increases in greenhouse gas emissions and a hotter planet. Cool roofs reduce that demand.

Cool roofs solve the challenge in areas that cannot be easily cooled mechanically. A simple and passive solution to areas where mechanical cooling is a difficult to apply or manage. Take garages, pergolas, patios, containers and sheds and more can have the solar thermal heat reduced through the correct cool roof solution...like Super Therm.

The less solar absorption by a roof ensures the thermal temperature in a roof space is reduced along with the heat load. Reducing roof temperatures ensures less heat is transferred into the building.

Thermal shock is the unseen asset expense on a building the continuous expansion and contraction of metal roofs causes corrosion. A cool roof stablises the roof sheeting therefore reducing thermal shock. Super Therm will also protect the roof further ensuring you can get another 30+ years of life savings thousands in re-roofing.

A Cool roof has been proven to reduce CO2 emissions. The reduction on need for mechanical cooling ensures there's less energy used. The CO2 results from reduced energy consumption has been proven time and time again.

A critical part of Cool roofs is the proven reduction of local air temperatures. Roofs cause between 25-35% of the urban heat island effect and less heat stored by roofs also reduces city and neighbourhood temperatures...particularly at night.

The reduction in energy consumption naturally lowers the demand for electricity but also peak energy. This reduction of energy therefore reduces the pressure on power failures.

Cool roofs are typically low cost investments. If the roof needs to be replaced anyway, choosing a white coloured material often costs the same as a dark coloured alternative

Paints are typically cosmetic in nature and significantly thinner applications than coatings and coatings are more reliably weather resistant.

In almost every case it is less than the cooling energy savings. While there usually is an increase in the demand for heating in winter, for cool roofs introduced in the right locations and the right building types this so called “winter penalty” can be insignificant and is much lower than the reduction in the cooling load (source).

Super Therm has a lower permeability rating and therefore, mould, moss, mildew and algae isn't able to grow. This ensures your health is good and roof stays clean.

Super Therm has been successfully tested at 23, 50, 75 and 100°C and performed the same. With the ability to block 99.5% of infrared heat...the hotter the better for Super Therm!

Due to the fact that air conditioners need to work hard to keep you cool, Super Therm reduces the solar thermal heat dramatically so the air conditioner doesn't need to work hard, is able to cycle...and in many instances not needed at all. This is a cost saving in power, servicing and extends the life of the machine.

It's a simple fact that when you reduce the heat entering the roof, you reduce the heat entering the bulk insulation. Bulk insulation slows the transfer of heat but cannot stop it, then releases it into the roof space at night. Cool roofs prevent the heat absorbing in the first place and this helps the bulk insulation work better instead of against you in your home when it hot.

Reduced energy use: A cool roof transfers less heat to the building below, so the building stays cooler and uses less energy for air conditioning. Reduced air pollution and greenhouse gas emissions: By lowering energy use, cool roofs decrease the production of associated air pollution and greenhouse gas emissions (EPA).

Research has shown that cool roofs have the ability to reduce urban temperatures and improve human thermal stress during heat wave conditions (source).

Cool roofs can be applied to any surface. Generally in Australia that is galvanised and tiled roofs. Super Therm, unlike many others doesn't require a primer and is a one coat solution, meaning it not only works on metal, wood and concrete but also is simply and easily applied and works instantly.

Its pure physics. Black absorbs heat and white reflects it...however the main difference is managing the infrared heat. Cool roof coatings that can reflect all forms of heat will work the best. You can have a tinted cool roof coating. The dark it is, the less effective it is. Super Therm can be tinted but we strongly recommend keeping it lighter for the best results.

Cool roofs have a variety of costs but that is related to their effectiveness, formulation and longevity. When you compare the cost of a cool roof it's cheaper than the cheapest carpets and it saves you money by saving energy, so in the end, it's return on investment can be within a few years.

Condensation happens when warm moist air comes in contact with a cold surface. Condensation is a surface phenomenon. The hot air is not the problem, the cold surface is. Therefore, in order to prevent condensation, the temperature differential between the air and surface must be reduced. Super Therm slows the rapid temperature increase of the cooled substrate. This means the cooling molecules don't convert to water vapour, therefore condensation. Not all cool roof products can do this because they don't block infrared heat.

Keeping cattle cool in agriculture means less heat stress, improved milk production and higher birth weight during calving season, producers spend a lot of money on fans, misters and extra ventilation. Unfortunately, a hot metal roof can be one of the main culprits of excessive heat. Of course, a metal roof keeps the sun’s rays off the cattle, but when you can literally cook an egg on the roof’s hot surface, that heat transfers down to the livestock (source). Cool roofs help the well being of all users.

Not every cool roof coating can last that long...in fact only Super Therm in its testing has proven to last over 30 years. Made from the best ingredients and formulation that proven worldwide ensures the cool roof investment is very long lasting.

A cool roof cools the air around the surface of the solar panels. This improves the efficiency and longevity of the panels. Because cool roofs also reduce the need for air conditioning this ensure you can have more solar power feed in. Cools roofs are great for solar systems.

The unquestioned strategy is to lift the roof sheets, try roll out some sarking that offers minimal R value and then replace the roof sheet. Alternatively the expensive exercise of replacing the roof which gains not thermal benefit. Tbe cool roof coating of Super Therm fixes so many issues and blocks 96.1% of the total solar heat transfer. It also protects the roof from thermal shock, saves money and stops moisture transfer...awesome investment!

Cool roofs are at the forefront of fighting climate change and passively saving energy and reducing CO2. There are a large range of reports on the benefits of cool roofs and the industry is growing due to its proven success. Super Therm has been used globally since 1989 and continues to reduce CO2, save energy and keep the planet cool.

Energy Star and CRRC ratings are important for rating cool roof paints and coatings. Their ratings focus on Solar Reflective Index (SRI) and 3 year performance. Unfortunately SRI doesn't measure heat load, therefore it tells only half the picture. You need to understand how much energy it can block. Super Therm only allows 0.070 W/m2/K to transfer. Blocking most of the heat. To truly verify a quality cool roof coating ensure it has high ratings and discloses all it's values.

Keeping cattle cool in agriculture means less heat stress, improved milk production and higher birth weight during calving season, producers spend a lot of money on fans, misters and extra ventilation. Unfortunately, a hot metal roof can be one of the main culprits of excessive heat. Of course, a metal roof keeps the sun’s rays off the cattle, but when you can literally cook an egg on the roof’s hot surface, that heat transfers down to the livestock (source). Cool roofs help the well being of all users.

Leading organisations globally including Princeton University, University of Reading, Roofing Magazine, USA Department of Energy, South Australian Government and Lawrence Berkeley National Laboratory along with a myriad of other’s have all stated that the ‘winter penalty’ is minimal over the benefits of summer gains.

Australian Government’s Nationwide House Energy Rating Scheme (NatHERS)

Star ratings and variations

To be effective, passive cooling needs to cool both the building and the people in it – Australian Government. According to the Australian Government, a 7 star rating is achievable with basic inexpensive materials such as aluminium windows and single glazing when the right design principles are applied—such as passive design and appropriate use of insulation and material selection.

The Building Code of Australia doesn’t take into consideration new and next generation solar heat block technology such as Super Therm® that blocks the heat entering the structure. NatHERS say in order to achieve a 7 Star rating building you need a roof colour of Surfmist® in Adelaide, Brisbane, Canberra, Darwin, Sydney and Windspray® in Melbourne and Hobart.

Colorbond® Contemporary colours range

The summer heat in Melbourne can exceed 40°C so to have a near 50% grey roof in Windspray® as a specified colour for a hot environment isn’t energy efficient. Interestingly Surfmist® is the lightest colour in the Colorbond® range above and is recommended for the rest of the country except Perth that has Classic Cream®.

According to the Australian Government graphic above summer heat gain is 25% to 35% through the roof. Blocking this heat would maximise all energy efficiencies in the home (Source)

Super Therm® Colorbond® Colour Roof Tints

Super Therm® can be tinted to the lighter range of COLORBOND® colours. Naturally due to physics, the darker the colours the less thermal efficient thermal barriers become which is the same for heat block coatings. Therefore we recommend these COLORBOND® colours that help improve thermal solar heat barrier and make your roof look fantastic.

Super Therm® is an egg shell white with a Total Solar Rating of rating of 96.1 (stops heat), Solar Reflective Index rating of 102 (reflects light and emits heat) and BTU rating of 99.5% (Blocks infrared), it can be tinted with water base dies to light colours by your local paint store.

IMPORTANT: Any tints and darker colours will cause a reduction in solar heat performance which is then influenced by the colour and the environment. The chart below is a colour guide to the reduction of efficiently with tints applied to Super Therm®. See COLORBOND® solar absorption ratings.

SUPER THERM® can be colour matched to these colours in the COLORBOND® steel range

7 Star rating and beyond

The application of Super Therm® to a roof would take the energy rating beyond 7 Stars, proven to save up to 20-50% in energy use (Industry testing) while lowering CO2 emissions and extending roof life. Super Therm® ceramic heat block coating technology blocks 95% of solar heat entering a building and used globally…that’s a game changer!

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