If it turns out the place is unfit to live in, I'll definitely be breaking the lease and want to make sure that I'm legally allowed to do so without incurring contractually-specified expenses.
http://www.palawhelp.org/resource/warranty-of-habitability?lang=EN
The Supreme Court decision says you can only use the Warranty of Habitability for serious problems and you must tell the landlord about the problems and give him or her a chance to fix them. A serious problem is one that causes a large amount of discomfort or creates a realistic danger of harm. Some examples include: lack of heat or water, a gas leak, frayed electrical wiring, improperly vented furnace or hot water heater, or a leaky roof resulting in structural damage to your home.
How much notice you must give the landlord before you can use a remedy allowed by the Warranty of Habitability depends on the problem. If the furnace is broken in July, the landlord probably doesn't have to fix it until the fall, but the same situation in January would require the landlord to make repairs within one or two days. While you can give the landlord notice of the problem in person or over the phone, you should also follow up that notice by sending the landlord a letter describing the problem, what you want the landlord to do about it, when you want the repairs finished and what you plan to do if the repairs are not made. Sending the letter by certified mail will help prove that the landlord received it, if that fact is disputed in court.
If the landlord does not make necessary repairs and you live in a city having a housing inspector, have the home inspected. The housing inspector can probably convince the landlord to make repairs to your home. In addition, the inspection itself may give you important evidence of the seriousness of your problem if the landlord takes you to court because you used a remedy available to you under the Warranty of Habitability. Nevertheless, take pictures or gather other evidence you could use in court to prove that your problem is real and serious.
If the landlord does not make the repairs necessary to insure that you have a home that is safe, sanitary and fit for human habitation within a reasonable time, the Supreme Court says you can do one of three things:
Cancel your lease and move. You will have no obligation to pay any more rent to the landlord and any clause in your lease that says you must pay a penalty for canceling the lease before the end of the lease term cannot be enforced against you.
Make the repairs yourself or hire someone to make the repairs and deduct the cost of the repairs from your future rent payments. It is important that if you choose this remedy you keep the invoice or receipt you get from the repair person. Make sure the repair person writes on the invoice or receipt the exact nature of the problem they repaired and what they had to do to fix it.
Withhold all or part of your rent. You should only withhold all of your rent if the problem affects your entire home. Lack of heat would be an example. If the problem only affects part of your home, deduct the percentage of the rent which represents the amount of the home that you can't use because of the problem. You can make such a calculation by estimating the total square feet of space in your home and dividing that amount by the square feet of the room(s) affected by the defect.
Please note: If you live in a city which has a rent withholding program find out if your problems are serious enough to qualify for that program. Your city housing inspector can probably tell you if your city has a rent withholding program and how to qualify for it. Rent withholding programs typically include a provision prohibiting a landlord from retaliating against a tenant who is found eligible to withhold rent.
It is very likely that if you use a remedy you have under the Warranty of Habitability your landlord will try to evict you by filing a Landlord/Tenant Complaint with the Magisterial District Judge. If this happens, you will have to go to the hearing and prove that a serious problem exists in your home, you gave the landlord reasonable notice to fix the problem, and the remedy you chose under the Warranty of Habitability was appropriate under the circumstances. You can file a countersuit for any damages caused by the habitability problems if you have already made repairs or otherwise suffered a monetary loss. An example would be excessive utility bills due to a malfunctioning furnace. See the pamphlet, 'District Justice Defense' for more information about filing a countersuit. If you have already moved from the home but suffered a monetary loss due to the landlord's violation of the Warranty of Habitability, you can file a Civil Complaint with the Magisterial District Judge for the amount of your loss. Review the pamphlet, 'District Justice Lawsuit' for more information about filing a suit in Magisterial District Judge court.