Hello everyone and welcome to the "Towards a greener world" blog where we share all the knowledge on how to improve our house energy usage and protecting the environment. What a great day to start. The weather is just nice and the ambient temperature will just make anyone feels sleepy. But whenever you want to go for a nap, sometimes your home or your room makes it a little bit not so comfortable in a way that it's humid or the air is dirty.
So normally we would go for an air-conditioning or an air purifier to be installed in the house. But did you know all these consumes electricity? With just some modification of the roof, these items may not be required and you can save on the energy bills.
So normally we would go for an air-conditioning or an air purifier to be installed in the house. But did you know all these consumes electricity? With just some modification of the roof, these items may not be required and you can save on the energy bills.
Energy Efficient Roof
Not everyone can have a living roof, but most people can have a “green” roof fairly easily. And the great news is that improving the energy efficiency of your roof doesn’t have to be costly. Small improvements can deliver a big difference, not only to your home’s energy usage, but also to the size of your energy bill. Do you know that in United States of America, people spent roughly around US$40billion a year in air-conditioning? Now that's a large amount of money.
An Energy Efficient Roof reflects more of the sun's rays. This can lower roof surface temperature by up to 10 degrees Celsius, decreasing the amount of heat transferred into a building. Thus it can help to reduce the amount of air conditioning needed in buildings, and can reduce peak cooling demand by 10-15 percent. Nevertheless, you will still need to consider the facility design, insulation used, climatic conditions, building location, and building envelope efficiency to fully utilize the benefit of the energy efficient roof.
Low-Sloped Roofs :- Low-sloped roofs are normally found on commercial buildings, industrial buildings and multifamily homes. They can be made more efficient through the application of cool coating or single-ply membrane. Cool coating is the consistency of thick paint and can be applied to existing surfaces, such as asphalt, gravel, metal and various single-ply materials. Cool coatings have additional benefits, including improved adhesion, durability, suppression of algae growth and an ability to self-wash under normal rainfall. Single-ply membranes come in prefabricated sheets and are generally glued or mechanically fastened in place over the entire surface of the roof.
Steep-Sloped Roofs :- Steep-sloped roofs are generally found on residential homes. The most common types of cool roofing systems for steep-sloped roofs include tiles and painted metal. Typical tiles, made of clay or concrete, reflect only 10 to 30 percent. "Cool-colored" tiles contain pigments that reflect 25 to 70 percent of solar energy, depending upon the color. Cool-colored metal roofing also contains pigments that reflect 20 to 90 percent. Metal roofing is more common than tile, as it is highly durable.
Heat Islands :- Heat islands are urban areas that are hotter than nearby rural areas. A city with 1 million people or more can be 1.8 to 5.4 degree Celsius warmer than its surroundings. Heat islands affect community-wide energy demands, air-conditioning costs, air pollution, greenhouse gas emissions and water quality. Cool roofs play a vital role in reducing the environmental and economic impact of large cities.
Green Roofs :- Although green roofs fall into their own category, they provide similar benefits as cool roofs. Green roofs are gardens or mini-ecosystems that cover an existing roof with the aid of special planters. The greenery essentially shades the roof, reducing heat transfer and thereby keeping the building cool. Green roofs also act as insulators in cold weather and have a host of other benefits, such as absorbing rainfall for better stormwater management, reducing air pollution and providing garden space in densely populated areas where parkland is rare.
An Energy Efficient Roof reflects more of the sun's rays. This can lower roof surface temperature by up to 10 degrees Celsius, decreasing the amount of heat transferred into a building. Thus it can help to reduce the amount of air conditioning needed in buildings, and can reduce peak cooling demand by 10-15 percent. Nevertheless, you will still need to consider the facility design, insulation used, climatic conditions, building location, and building envelope efficiency to fully utilize the benefit of the energy efficient roof.
Design
When it comes to design, there are many types that are available in the market but I'll just name a few in here:
Cool Roofs :- "Cool roofs" is an umbrella term for several different roofing systems. In short, a cool roof is a roof designed to reflect sunlight and heat. Conventional roofing materials reflect only 5 to 15 percent, which means they absorb 85 to 95 percent of the energy and heat from the sun. The coolest roofing materials reflect more than 65 percent, absorbing 35 percent or less of the energy from the sun. Thermal emittance determines how readily a surface gives up heat. Ideally, a roof will have a high percentage of reflectance and a high percentage of emittance.
Steep-Sloped Roofs :- Steep-sloped roofs are generally found on residential homes. The most common types of cool roofing systems for steep-sloped roofs include tiles and painted metal. Typical tiles, made of clay or concrete, reflect only 10 to 30 percent. "Cool-colored" tiles contain pigments that reflect 25 to 70 percent of solar energy, depending upon the color. Cool-colored metal roofing also contains pigments that reflect 20 to 90 percent. Metal roofing is more common than tile, as it is highly durable.
Heat Islands :- Heat islands are urban areas that are hotter than nearby rural areas. A city with 1 million people or more can be 1.8 to 5.4 degree Celsius warmer than its surroundings. Heat islands affect community-wide energy demands, air-conditioning costs, air pollution, greenhouse gas emissions and water quality. Cool roofs play a vital role in reducing the environmental and economic impact of large cities.
Green Roofs :- Although green roofs fall into their own category, they provide similar benefits as cool roofs. Green roofs are gardens or mini-ecosystems that cover an existing roof with the aid of special planters. The greenery essentially shades the roof, reducing heat transfer and thereby keeping the building cool. Green roofs also act as insulators in cold weather and have a host of other benefits, such as absorbing rainfall for better stormwater management, reducing air pollution and providing garden space in densely populated areas where parkland is rare.
Cost
Make your decision based on your budget and your planned tenure in the home. There are so many options such as metal roofing but the costs vary wildly. I actually saw in a forum of a local manufacturer that specialized in commercial roof and his costs were 40% lower than the franchise metal roofing contractor. Even so it was 300% higher than an asphalt shingle roof. You'll have to look at your variables and make a decision that works for you. I wouldn't recommend a solar reflective roof unless the added cost is minimal (3 – 5%).
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