In places where electricity is not predictable or is expensive, it pays to explore other ways to reduce heat:
1. Use paint that reflects heat on your roof.
Painting your roof white can cut temperatures noticeably, by as much as 10 deg. centigrade. Roof-paint can be simple white-wash, which might need to be reapplied every year or so. Or, you can use paints that are designed to be reflective (high albedo), which are more expensive but last longer.
Hiten Chavda, lead architect of Bio-diversity Conservation India Limited (BCIL) says that over 70% of heat in a building enters through the roof and is heated up quickly, especially by infra red and ultra violet rays of the sun. Building materials being good conductors of heat radiate this to the inside and trap it there. While the rest of the earth cools down after the suns sets, our homes are still warm inside. To combat this, Chavda says, roofs can be painted white as the colour reflects a large part of the sun’s rays back in to the atmosphere, thus reducing the heat absorbed by the building. Temperatures, Chavda says, can differ by as much as 10 degree centigrade between painted and non-painted roofs. To get the best effect, he says, high albedo paint should be used. “High albedo paints are highly reflective and can reduce conductivity of heat considerably. In our buildings, we have found reduced energy consumption for cooling drop by as much as 20%,” he says. Temperature difference before and after painting the roof white. Pic: Yograj S Mudalgi White roofs can even help reduce the ‘Heat island effect’ one of the causes for rising temperature in urban areas. Concrete structures and tarred roads not only heat the surroundings, they also trap it. So urban areas become islands of heat. But with white roofs, more heat is reflected back in to the atmosphere, cities can remain cooler. Naresh Narasimhan, principal architect at Venkatraman Associates, an architectural firm based in Bangalore says it has been long since benefits of painting roofs white have been known. “Not only can they keep homes cooler, if all surfaces in the city are painted white, they will bring down the temperature of the area considerably,” says Narasimhan.Read more at: http://bangalore.citizenmatters.in/articles/2951-paint-your-roof-white-stay-cool-?utm_source=copy
White reflective paint can be used on exterior walls, compound walls, and anywhere else to diminish heat.
2. Landscape to block heat:
A few trees around the house can make a huge difference to how much sun gets absorbed by the walls and conducted into the interior. While trees take a while to grow, you can substitute vines, which grow rapidly. 10-15 foot high trellises can be fully covered within 6 months and form an effective barrier against heat. Shrubs can block heat from being absorbed lower down. They too grow fast and are easier to care for than trees.
Cape Honeysuckle does well in very hot climates, can withstand drought after establishment, and grows very rapidly to form a thick bush or a dense vine that gives excellent protection from the sun and vivid color. Its bark is medicinal.
3. Use awnings outside the window and blinds/curtains inside:
It is not common to see awnings in India. Instead, builders usually incorporate concrete ledges that jut out over the window. They need to be combined with outdoor and indoor blinds for maximum cooling.
Exterior bamboo blinds are especially effective.
This eco house in Brazil has aluminum trellises mounted against the walls, on which vines are being grown, keeping the walls protected from the heat.
4. Shade structures in the yard keep the weeds down and provide protection from the sun.
Here are several examples. Living walls (plants grown vertically on a wall) are another option.
5. Grow plants on the terrace in wooden boxes, lined with plastic to prevent water leaking. The mud and foliage absorb heat that would other wise enter the house. Window-boxes also help cool temperatures.
6. Add a roof-structure, solar panels, or even an open water-tank to cool the roof. Inside the house, false ceilings are a possible way to reduce heat.