Promoting environmentally sound technologies

It is not that that conservation, efficiency, and new technology won't help. They will -- but the help will be slow and expensive. The tremendous momentum of growth will work against it. If tomorrow a new furnace that used half as much oil as old furnaces. How many years would it be before a substantial number of homes had the new device? And what if it cost more that other furnaces on the market? And if oil stays cheaper per litre than bottled water?