Service tax on income from house

SERVICE TAX ON RENT

I am in receipt of rent from two properties. one is residential and annual rent is Rs. 660,000 and another is a commercial office for which annual rent is Rs.  600,000. Total Rent is 12,60,000/- .

Am i liable to charge and pay service tax in respect of my rent from the commercial office or as i do not fall within the ambit of service tax as residential property rent is exempt.

thanks and appreciate early advice