Saving Electricity

Saving Energy with Thermal Cooling Roof Coatings

Special roof coatings are saving electricity and energy in hot climates and can help utilities reduce peak demand.

Thermal cooling coatings can help reduce the indoor temperatures of buildings to below ambient. ( not needing air conditioning )
Architects are using special coatings to cool off buildings in hot climates, but until recently there was little research on the measured cooling-energy savings of these roofs.

Over the past two years, however, researchers in Florida and California have examined the impact of these roof coatings on air-conditioning energy use in retrofits of monitored homes. Simulation analysis suggests that a specially coated roof can cut a building’s cooling load by 10-60%. The higher numbers are associated with uninsulated roofs.

Cooling coatings are increasingly being used for manufactured homes in the Southeast, based on homeowner reports that such coatings can reduce summer air conditioning costs. Until now, however, no investigation in a cooling-dominated climate examined the effect of coated roof on time-of-day air conditioning electrical demand in occupied residential buildings–important information for utilities where summertime peak demand is a concern.

One of the earliest whole-building studies that measured cooling-energy savings from cool roof coatings was performed by the Mississippi Power Company. The utility monitored two identical side-by-side single-story commercial office buildings after the roof of one had been covered with a cooling coating. Both existing buildings had R-11 roof insulation. The results of the experiment? Summertime air conditioning was reduced by 22% in the building with the reflective roof coating.

More recently, researchers at LBL measured very significant cooling-energy savings from applying cooling coatings to three buildings in central California . At one site, energy demand for space cooling was nearly eliminated. But regardless of the potential of cooling roof coatings in California, Florida’s higher humidity and nighttime temperatures make prospects for near elimination of space cooling energy use in that state very unlikely.

Save electricity with Sno-Coat™

Sno-Coat™ is an advanced roof cooling paint as well as radiation barrier for buildings. Our product can reduce internal temperatures to below ambient, leading to significant cost savings on air conditioning and also contributing to environmental sustainability.

Use Sno-Coat™ on the roof of the building or structure as well as the walls where necessary, for the purpose of cooling the building or structure dramatically.

Air temperatures measured inside buildings can drop by up to 15 degrees centigrade and temperatures of roof sheets or walls can drop by up to 35 degrees centigrade.

Sno-Coat™ is a liquid paint coating, radiation barrier that is highly effective as a reflector of radiation, confirmed by SABS tests.

see the Sno-Coat™ video

Suitable Uses for Sno-Coat™

Shopping Centres as well as Cash and Carry wholesalers.

Hotels, Lodges as well as Churches.

Poultry houses as well as Farm houses,

Seed warehouses as well as Grain Silos.

Fruit packing, processing sheds, fresh vegetable sheds as well as warehouses.

Tobacco sheds, Food wholesalers as well as supermarkets.

Houses, Factories, Schools as well as Clinics.

Office Buildings, Store rooms as well as Convention Centres.

Garages, dormitories, astronomical observatory domes as well as Dish Antenna.

Bus/Taxi ranks, informal shelters as well as under cover out door markets.

 In Addition to the above, any structure with a roof that is too hot.

Sno-Coat™ Enamel is an advanced enamel roof cooling paint that can reduce indoor temperatures to below ambient, leading to significant cost savings on air conditioning as well as contributing to environmental sustainability.

You also don’t need to use a primer with this product.

Sno-Coat™ Enamel shows excellent resistance to rust show through and also leaves a gloss smooth finish to the substrate.

Our product has superior adhesion propensity, better opacity, extended coverage, higher cooling capacity and is also chip blister, crack and peel resistant and displays excellent rust fighting capabilities.

See the Sno-Coat™ Enamel Demo video

you might also like

advanced roof cooling paint that reduces indoor temperatures and works on most surfaces

Sno-Coat™ Ecology works on IBR, concrete, cement fibre and also harveytile roofs.

When used in conjunction with our primer Dead-End™, Sno-Coat™ achieves a 100% adhesion as tested by SABS.

THE BEST PRIMER TO USE WITH SNO-COAT™ ECOLOGY IS DEAD-END™ 

Dead-End™ provides a fantastic interface between the surface and the coating, making the paint go further and the finish last longer!

ADVANTAGES of the Sno-Coat™ range

Thermal Insulator (Cools) as well as Acoustic insulator.

Seals asbestos fibre roofs (Government regulations) and also saves electricity and Energy.

Waterproofer as well as Rust Protector/Inhibitor.

Water-Based, Non Toxic as well as Long Lasting.

Easy to apply as well as Inexpensive.

Addresses climate crisis issues as well as Combats climate change.

An Initial Experiment

In the summer of 1991 we conducted a preliminary experiment in Merritt Island, Florida. Our first test building (Site #0) was a 1,800 ft2 detached single-family, single-story home of conventional concrete-block construction. The pitched roof faced north-south, with plywood decking covered by green/gray asphalt shingles.

The home’s attic was well insulated with approximately two inches of fiberglass covered by an additional six inches of cellulose insulation, yielding a thermal resistance of about R-25. Air infiltration from the attic area into the conditioned interior (a common problem due to duct leakage), had been largely eliminated in a previous audit and retrofit.

Beginning in May 1991, we submetred the home’s air conditioner while maintaining a constant thermostat setting of 79deg.F. We also recorded the underside roof deck, attic air, and living room temperatures.

When we applied the cooling coating on September 5 of that year, the roof’s reflectivity increased from 0.22 to 0.73.2 Spot measurements under full sun at midsummer had shown shingle surface temperatures of 160-170deg.F, prior to the roof treatment, compared to 110deg.F after we applied the coating. Analysis assuming an 81deg.F average summer temperature indicated that a cooling roof coating would reduce energy consumption by 10% (35 kWh versus 39 kWh per day).

Yet this test house probably understated the savings, since most existing Florida residences have fairly poor attic insulation and attic air frequently leaks into the conditioned interiors. Therefore, we obtained more “typical” residences for the detailed experiments we conducted the following year.

View a Full 5 house study for Sno-Coat™

Technical Information

Sno-Coat™ is a wet in the can paint on coating with thermal insulating, rust preventing and other properties.

Can reduce air conditioning installation and running costs by up to 25%

 Reduces thermal shock by up to 50%

Increases rust onset and degradation time by up to 300%

Prolongs substrate life by up to 300%

Increases live carry capacity by at least 25% (Chicken house)

Decreases heat stress mortality by more than 90% (Chicken house)

Summer inside temperatures decrease by up to 30%

Roof substrate temperatures drop by up to 50%

Excellent waterproofing properties.

Aesthetically pleasing

         Table 1: Solar Reflectance Index (SRI) for Typical Roofing Materials

Source: LBNL Cool Roofing Material Database. These value are for reference only and are not for use as substitutes for actual manufacturer data

SABS TESTS CONDUCTED AND RESULTS OBTAINED
Thermal Insulation Coating.
Test report 7222/ 2090038/v 76

Product was tested for:
Heat absorption of air inside treated and non-treated containers.
Adhesion of thermal coating.

Test methods:
Adhesion – requirements in accordance with SABS ISO 2409 : 1992
Two containers – one coated one non-coated.
Inside temperatures measured with thermocouple at 1 hour intervals
Between 11:00 and 15:00.

Test window:
12 April 2002

Results:
Adhesion – 100 % adhesion, no loss.
Inside Temp – Temp in coated container is always lower than uncoated by approx. 18%.
As ambient temp. drops air in coated container drops slower than uncoated container confirming insulating properties

What About the Payback?

A frequent question concerns payback of cool roofing. There are several angles on the answer, but generally speaking, cooling coatings are most appropriate when one is re-roofing. If the coating is applied to an existing roof that is in otherwise pristine condition, the cost equation is straightforward. The typical coverage of a cooling coating is 25 ft2 per gallon,(0,6 sq. meters per liter) (Sno-Coat® gives 6 square meters per liter reducing the application cost factor by a factor of 10!!!!

This makes a massive difference to these calculations and results) based on an application of two coats to a target thickness of 40 mils.

Cost for the material from vendors varies by 50% or more but averages about $60 per 5-gallon container when purchased in quantity. It is important to keep in mind that roof area is generally considered greater than building floor area, particularly with a steep roof pitch. For instance, a typical 1,500 ft2 home may have 2,200 ft2 of roof to be covered. The application then requires 90 gallons of coating material for a materials cost of approximately $1,100.

The cost of labor for installation depends greatly on the roof surface, on whether the coating is to be rolled on or sprayed, and on labor rates. A typical labor cost might be approximately 50cents per ft2 for the required two applications. Thus the overall application would cost about $1 per ft2, or approximately $2,200 for a typical home. With annual energy savings in Florida of $35-$140, the payback times are long–usually lasting longer than the roof itself.(With the exception of Sno-Coat®)

A completely different scenario emerges if the home is soon in need of re-roofing, however. Here the roof coating (which essentially creates a new weatherproof surface) might be seen as a way of extending the life of the roof by 5 to 10 years at half of the cost of re-roofing. The energy savings then become a side benefit.

For new homes, the situation is even more interesting. Here it is often possible to choose roofing types–such as metal roofing, tile roofing, or metal or ceramic shingles–that can be specified in a reflective white at significant additional cost.

Unfortunately, no truly reflective asphalt roofing shingles yet exist for the residential market, but this situation may change as researchers work with the roofing industry to develop new products and spread the word about the energy benefits to help create a market for the materials. For commercial buildings, a variety of reflective roofing materials are already available: Hypalon, white EPDM, and PVC single-ply membranes.

Once such products are widely available for the residential market, the economics may be significantly altered as the cost of reflective roofing becomes inconsequential.

Notes

1. Reflectivity or albedo is the hemispherical reflectivity integrated over a particular wavelength band of the electromagnetic spectrum. For the purposes of this article, the terms reflectivity and albedo are used interchangeably and refer to the wavelengths encompassing the range of solar irradiance from 0.28 to 2.8 microns.

2. Surface solar reflectivity is measured using a precision spectral pyranometer with the device alternately faced upward towards the sun and downward towards the roof to determine the ratio of incident to reflected solar radiation.

Urban Heat Islands

Large cities typically contain darker surfaces and less vegetation than rural environments; these circumstances increase solar gain and thereby raise summertime cooling-energy demand. The dark surfaces and lack of vegetation also warm the summer air, leading to the creation of the urban “heat island.”

In fact, the average temperature in a typical city on a clear afternoon can be 1deg.F-5deg.F hotter than that of the surrounding rural area. Researchers at LBL Heat Island Project estimate that the additional air-conditioning use caused by this urban air temperature increase is responsible for 5%-10% of urban peak electric demand, at an annual cost of several billion dollars.

The power needed to compensate for these higher temperatures requires additional generating capacity, which often contributes to urban air pollution. Moreover, the elevated temperatures themselves accelerate smog formation. According to researchers with LBL, the probability of smog increases by 2%-4% per deg. F increase in maximum daily temperature. But shade trees and light-colored surfaces can offset, and may even reverse the summer heat island effect.

In one experiment, LBL examined the savings due to cooling roofing systems installed on three buildings in Sacramento, California. One was an occupied residence with R-11 ceiling insulation under a composite shingle roof. The initial roof reflectivity was measured at 0.18, and this was altered to 0.78 by application of a cooling roof coating. Furthermore, the air-conditioning cooling load in the building was reduced by 69%, with a 28% reduction in peak electrical demand, and the seasonal energy savings amounted to a reduction of approximately 14 kWh per day and a 1 kW in peak power demand.

The second and third buildings were test bungalows. In both cases, the buildings’ corrugated metal roof albedo was increased to approximately 70%, and measured air conditioning energy use was reduced by approximately 40%-50%.

Temperatures after using Sno-Coat™

Below are tables that show the temperature differences between roof with and without Sno-Coat™

The above temperatures are in deg. F (Average about 74,5) this relates to only 23,61 deg. Celsius. Yet at these
only slightly above room temperature temperatures, there are huge electrical savings in air conditioning
electrical consumption as seen below. In typical South African conditions where temperatures indoors frequently
reach to over 30 deg. C the electrical savings are massive. Bearing in mind that the higher the ambient temperatures the more effective Sno-Coat™ becomes.

Air Conditioning FAQ

Costs are in AUS$
Multiply by 7 for ZAR

Use a rule of thumb of about 600 Btu per square meter of floor area to be air conditioned

9000 Btu of cooling output equates to 2.64 Kw of cooling wattage which requires 1000 watts of electrical input which will cost about R0.75 cents per hour.

The above electrical consumption costs don`t take into account maintenance or initial installation costs which can increase the above savings by a factor of 3

1 Kg of air is about 850 liters in volume

The specific heat capacity of air is about 1 –  i.e it requires about 1 KJ to  heat 1 Kg of air by 1 deg.C
1 KJ is approx. .95 BTU

Air conditioning costs calculator

Air conditionng electric running costs http://michaelbluejay.com/electricity/cooling.html

Test results for Durban CBD

The following are temperature recordings taken in Durban CBD on an asbestos roof.
The ambient temperature was 30deg. C

TEMPERATURE RECORDINGS FOR COSMODEC PAINTED ROOF VS NORMAL PAINTED ROOF ETHEKWINI MUNICIPALITY

Temperatures are measured in degrees Celsius and readings recorded were all at similar times ie within 10 minutes of one another. Temperature sensors were placed in the ceilings of both H&S and First Aid buildings on the OFP Complex and ambient temperatures measureD in the shade between the two buildings.

“Must it Be White?”

Many considering the potential of cooling roof coatings  are concerned about color. The FSEC has evaluated the solar reflectance of some 37 different roofing materials, with the measured data showing that white roof materials generally exhibit the best performance.

They are highly reflective across the solar spectral bandwidth, while being highly emissive in the far-infrared region–this is another way of saying they strongly reflect solar heat and any heat they absorb will readily re-emit to the cooler sky temperatures.

It may seem a bit counter-intuitive, but silver reflective aluminum paints do not perform nearly as well as others.  This is because, although the aluminum flake paints have a high solar reflectance, they also have a low infrared emissivity–they tend to hold whatever heat they absorb–negating  the cooling properties.

Fortunately, for those who demand non-white roof colors, it appears possible to tailor paints and pigments so they are not so reflective in the visible solar range, but are very reflective in the “invisible” near infrared region. The Navy has conducted research in this area to help develop infrared reflective coatings.

What are the best colours according to science

Paints have been created that are twice as reflective in the near infrared as in the visible region. Researchers with LBL are examining spectrally selective paints that offer the possibility of significantly increasing the solar reflectance of even darkly pigmented colors.

Physics suggests green-colored pigments with large particle size may further enhance the performance of solar reflective non-white paints. Even so, such coatings will not likely perform better than materials that are uniformly very reflective access the solar spectrum–particularly since the energy intensity of solar radiation is greatest in the visible bandwidth.

Regardless, such developments promise to provide improved roofing materials with high albedo, while still preserving the designer’s pallette of colors.

It may also be possible to tailor the properties of white reflective coatings to create superior performance. An ideal coating would be very reflective across the entire solar spectrum, while being very emissive in the long infrared region so that heat is readily re-emitted.

Research shows promise in this area. One specialty coating, used to coat astronomical observatory domes, has a 98% solar reflectivity–so high that the temperature of the material is only slightly higher than air temperature under moderate solar intensity. Thus, it may be possible to tailor the composition of roof coatings to further optimize their performance.

Can we mold Climate protection into society?

Lifestyles are changing as a result of climate change, and this is creating a blueprint for more energy-efficient homes of the future. Property players believe climate proofing will soon be a requirement in order to sell homes.

In his Nobel Prize-winning documentary on climate change, An Inconvenient Truth, former US vice president Al Gore made the point that something needs to be done urgently if the world is to avoid a crisis caused by global warming over the next few decades.

“We can already see the effect of climate change on lifestyles as more and more people become aware of this fact,” says Mike Bester, CEO of Realty1 International Property Group, “However, the South African residential building industry does not yet have this issue at the top of its priority list.”

“The Eskom crisis has led to some increased awareness of so-called ‘green’ alternatives for power, but as yet there are very few initiatives to develop more holistic environmentally-friendly housing,” says Bester. “The country is so far behind when it comes to providing housing for the masses that green issues are at the bottom of the list. This means that only homeowners building privately can actually give proper attention to the issues.”

Is anything being done?

In May 2005, a report by the South African National Biodiversity Institute (SANBI) stated that as a result of the ‘greenhouse’ effect, South Africa would experience a “steady warming of three degrees Celsius within the lifetime of the present generation of children”. This means homes will need some form of insulation or will have to resort to energy-hungry air conditioning in an effort to keep the occupants cool.

“This has resulted in a wave of interest in environmentally-friendly building initiatives that are setting the stage for the homes of the future,” says Bester, “and we are seeing more homes built that incorporate alternative sources of energy and climate proofing. The homeowners will reap the benefits both through improved lifestyle and increased property values.”

And the authorities are also starting to come to the party, says Bester. As part of the Kuyasa Project in Khayelitsha on the Cape Flats, low income homes were retro-fitted with energy saving options such as insulated ceilings, low-wattage bulbs and solar water heaters.

The project demonstrated a saving of 2.85 tons of carbon dioxide per household per year and is being hailed as a blueprint for future developments. In the past few months, the first 60 of 240 Eskom-accredited solar geysers have been installed in the KwaNokuthula community in Riversdale with more to follow in areas such as Nyanga, Elsies Rivier and Atlantis.

Bester believes that the time will come when a property that does not comply with the energy efficient regulations of the future will be impossible to sell. “Although it may seem unnecessarily costly now to renovate for climate change,” he says, “not only will suitable climate proofing help reduce current energy costs, but it will greatly improve the chances of selling the property in the future.”

Related articles ( click the links )

Property market must get ‘greener’

Cities under growing pressure

Eco-friendly homes a blueprint for future developmentsWhat’s your home worth?

View our full product list

NEED TO GET IN TOUCH WITH US?

LIKE US ON FACEBOOK AND SUBSCRIBE TO OUR YOUTUBE CHANNEL

Cosmo-Dec Everlasting Coatings originated in 1991, with a single product – Therma-Masta™.

Knowledge gained from manufacturing this complex and unique product allowed us to formulate new and innovative products such as Fire-Guard™, Aqua-Mite™, Aqua-Therm™, Clean-Air, etc. for specialty applications.

To-day, 3 decades on we manufacture more than 50 different types of construction chemicals out of our factory in Pretoria, Gauteng.

Deliveries

Easily view products & add them to your cart, once you decide to check out your total will be calculated including taxes and delivery, at which point you will be able to pay through our secure Payfast service.

We pride ourselves on the fact that our products are aimed at conscientious customers who demand value for money and insist on quality and longevity.

Our business includes managing contracting teams where we apply the products for customers as well as give advice.

We are happy to share our many years of knowledge gained from manufacturing and contracting with our customers ensuring successful applications for all concerned.

We are continually adding new and improved products to our already impressive list and will look at developing new specialized products for customers, making us a customer driven innovative business.

Customer service is a non negotiable process for us and this concept is drummed into and readily accepted by our dedicated staff.