At this time two industries are recognized as the fastest growing in the US, one of which is a 'hot' franchising concept.
The fastest growing industry right now is 'Management, scientific, and technical consulting services'...with the amazing technical advances and new technologies continuing to be developed, it is no wonder why this is the fastest growing industry at this time. A key factor, beyond the evolving technologies, is the fact that every American uses various forms of technology on a consistent basis and so the demand for consulting services (or, more simply stated, someone to assist in using this technology) has grow exponentially.
The second fastest growing industry in the US at this time is "Service for elderly and persons with disabilities'. Health care services, specifically in-home care, is growing at an amazing rate and is driven partly by demographics. According to the US Census Bureau and the Bureau of Labor statistics, the number of people 65 and older is expected to increase to nearly 46.4 million by 2016, from 35.6 million two years ago. The sector as a whole is projected to add 4 million jobs through 2016; that includes 480,500 home health care aids and 512,500 nursing home workers.
Seniors are the fastest growing segment of our population and many strong business owners are realizing the tremendous financial and personal rewards that come with serving the aging population.
Personally, I don't think that there is one concept that can be called "hottest" across all industries. Also I feel that a lot of marketing and PR determines what we call "hot". So to be frank .... people should we wary before believing claims of "hottest" or "fastest growing".
In reality what's "hot" to some may not be to others. As for making a franchising decision for your business goals .... pick something you have a passion in. Don't just choose on "hot" .... rather choose on what will most make you happy. If you have no passion for the "industry" you're less likely to stick it out through the rough times. But if you love what you do .... you'll be in it for the long haul and have a much better chance at success because of that. Plus you'll enjoy the journey more.