If you used the home equity line of credit for a business you are operating then yes you can claim the interest. If it was used for personal items or personal debt repayments, then no. It has to show clearly how the money was used. If for a business - yes you can claim it.

You can claim 50% of your mortgage interest if you have a rental suite. ( assuming suite is half the size of your house) Of course then you have to declare the income from the suite also.

rent increase is also interest rate. For 2011 it is 0.7 percent