Hi @Naveen Desai
Thermal imaging is used for a variety of reasons. In real estate it was originally used by energy companies to help homeowners determine where insulation or window replacement was needed to improve the thermal performance of the home (both cold and hot weather). You might be interested in the following link
http://www.greenbuildingadvisor.com/blogs/dept/mus...
Last year I attended a class through the North Texas Association of Real Estate Investors on code compliance. Evidently Texas has adopted to follow the International Energy Conservation Code and each community in North Texas has adopted different versions of this code. Additionally, some communities are applying these to rental units. So you might want to check with the particular city.
Beyond detecting thermal leaks thermal imaging is used to find hot spots in electrical systems and areas where water leaks are present, but not visible. Additional information on thermography can be found at
en.wikipedia.org/wiki/Thermography