Your Home as Green Pilot-II

Saving energy at your home or small office can start with small steps

Monday, June 01, 2009

Print

Comment

Email

Digg

Del.icio.us

Reddit

Twitter

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.

Page(s)   1