Your Home as Green Pilot-II

In my April column “Your Home as a Pilot Project”, I covered a few things you

could do at home to save energy: Cover up the rooftop to cool your top floor.

Switch to efficient lighting (and save capex). Add accessible switches to cut

out stabilizers, etc when not in use. Use natural light. Use coolers along with

air-conditioning.

I got a fair bit of reader mail on this, and am taking up a few of them here.

Covering up the top floor with fiber sheets sounds expensive-you spend a lakh.

Is there something cheaper? My top floor heats up and I spend a lot on cooling.

What can I do? I am also not very keen to block off my terrace permanently as we

do use it as an open-air venue. Raja Karmakar, Mumbai Your best bet is to paint

your rooftop with reflective (“high-albedo”) paint. You can get this from the

major paint suppliers such as Pidilite. On a building with a 7,500 sq feet

rooftop in Hyderabad, such a coating brought the surface temperature down from

52 to 32 degrees C, and cut cooling needs 8%, saving Rs 50k a year in power.

(See tinyurl.com/hydroof)

Thanks. I've also heard of 'green buildings' using spray-foam material for

the best insulation. Can you tell me more about this? Raja Karmakar, Mumbai

Spray foam is used for achieving a high level of insulation across the

house-roof, walls, window gaps, etc. There's open-cell (cheaper) and closed-cell

(more effective) spray foam. However, it can be expensive. For simply tackling

the issue of a rooftop exposed to sunlight, high-reflectivity paint is good. For

more details see tinyurl.com/spf67 or tinyurl.com/hw673 or just google for

“spray foam”.

We have to keep high-power outdoor halogen lights on, through the night. How

can we save? Rajiv Bakshi, Bangalore Keep CFLs on instead. And connect those

high-power halogens through a motion sensor with a 'daylight switch' so they

come on only at night and only if motion is detected.

Who makes these motion sensors? What do they cost and where can I buy them?

What else can I use them for? Rajiv Bakshi, Bangalore

There are many manufacturers of motion sensors, such as Honeywell, Philips,

Secom: see tinyurl.com/sens7. You can expect to spend Rs 3,000 or so for the

home-use ones. They're good for any device that should be on only when there's

people around. Some Japanese TVs now shut off if they see no motion in the room

for 20 minutes. Office or living-room ACs can be controlled through such sensors

(not bedroom ACs, else they'll go off when you fall asleep!)-see tinyurl.com/hvac8.

I read your piece "Your Home as a Pilot Project" and noted your reference to

asbestos as if it is a harmless material. I wish to inform you that asbestos is

a known cancer-causing fiber. The lung cancer caused from it is incurable. India

continues to import the asbestos toxic mineral primarily from Canada and Russia

although over 50 countries around the world have banned it. Controlled or safe

use of asbestos is not possible. Gopal Krishna, New Delhi

I used asbestos (the word, not the material) very loosely, picked up from the

contractor and workmen I employed who called these corrugated sheets 'asbestos'.

Further research shows that the opaque corrugated sheets I used say “ACC fiber

cement sheets” and are not asbestos. The translucent sheets are fiberglass

sheets.

Prasanto K Roy



pkr@cybermedia.co.in


is president and chief editor at CyberMedia's ICT Publications.