Is it legal to get evicted for non-payment during winter if we went without heat for 2 months and the landlord stopped and looked at the furnance but never came back to fix it?

You may have a defense to eviction, if the reason you did not pay was that you were withholding rent for the period of time there was no heat. All rentals come with what's known as the "implied warranty of habitability," or the obligation to provide a rental unit that it is "fit for its intended purpose"--in this case, residence or occupancy. A failure by the landlord to provide a unit fit for residence after notice from the tenant of a serious problem, like a lack of heat, violates this warranty. This violation can provide grounds to excuse the tenant from his/her obligation to pay rent. You may also be entitled to monetary compensation for the time you lived without heat.

You should get a landlord-tenant attorney to represent you; it's not always easy or straightforward to make out a habitability defense to eviction. If you cannot or do not get an attorney, then 1) make *sure* you show up for court, if the landlord takes you to court to evict you; 2) have the rent available to deposit with the court, if the court wants it--in these cases, courts sometimes require the tenant to deposit the unpaid rent, which will be released to the landlord when the problem is fixed, and a failure to deposit may let the eviction go foward; and 3) bring with you evidence of your attempts (e.g. emails, text messages, letters, etc.) to put the landlord on notice of the problem and get it fixed.

Note that if you failed to pay months when you did have heat--for example, say that the nonpayment was for fall months, not the winter months when there was no furnace--then the habitability defense is  probably not available to you, since your non-payment would not have been related to the furnace issue.