Can I legally hold my rent?

I contacted my landlord regarding a broken furnace. If my landlord hasn't made any moves to get this fixed even though he said he would, can I legally hold my rent? I have a one year lease but I was under the impression that it was the landlords responsibility to fix major appliances such as the furnace. I have a 4 year old son and need this furnace before winter really hits. Can I hold my rent and not be penalized legally?