r2i forum

Has anyone gone with better walls than traditional brick walls to get better thermal insulation? Has anyone tried the polyurathelene type insulation material in India? The ones that are used in the walls on the outer of the homes?

Anurajesh, the walls are not a big factor in terms of thermal loss. Heat loss through 9" brick walls (common in residential constructions) is fairly small.

Commercial constructions use thinner concrete walls to help with cost but make up for it by using aluminum claddings (which are excellent for their low emissivity properties). For them, these solutions are still cost effective since the utility rates for commercial establishments are 3x that of residential ones.

For residences, you can make a huge difference to your energy consumption by addressing the energy gain through windows and doors.

Do we get double pane windows in Hyderabad, India?

When you make the window, tell the carpenter to put two panes with a spacing of about 12mm. That's what we did. But with this method you should be careful that the inside surfaces are spotlessly clean (you will never be able to clean them once they are installed).

To make it more energy efficient, you should opt for low E coated glass for the outside surface (if it has sun exposure). Low E glass is available from Saint Gobain. Some folks use stickers or colored glass but that will cut the amount of light that comes in. Low E is more expensive but it is as if you have no tints or stickers. You get almost as much light as plain glass.

If you buy the whole window set (e.g from Fenesta), they will do all this. The negative with Fenesta is that the windows are made of PVC, which does not look as aesthetic as natural wood. But PVC lasts for ever and functionally is fine.