PA landlord tenant laws, rental property repair of furnace and central air unit, tenant's rights

Prompt property repair and new Lease!: Our furnace/central air unit failed back in February, causing carbon monoxide to fill the entire house we rent and caused a layer of soot to land on everything. Our landlord had the unit replaced, however the duct work then was not sufficient for air flow to the second floor. Our landlord was informed but hasn't had it fixed yet. So, during the past 7 months we have had to have either three electric heaters (a safety issure in itself) or two air conditioning units running upstairs along with the heat or central air. This has caused a great increase in our electric bill. I have tried to contact the landlord numerous times and he still has not had it fixed. He decided to present me with a new lease with an increase in rent, changed the date it would be due and wants all the utilities put in my name. And again the unit is not fixed. Do I have to sign and follow this new lease? Do I have any rights to dispute it since this issue is not resolved and it has been 7 months? Please Help!
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