I live in Upstate NY. My house is 121 yrs. old. The previous owner painted the house before we bought it 6 yrs. ago. It looks like they used lead paint. A lot of crackling and chipping has occurred in the old paint. I am wondering what would be the best primer (type) and paint to use over the old paint while taking into consideration I live in the north-east where we have long cold winters.
First allow me to suggest with certainty that lead based paint was not used. This product has not been available for consumer use since 1972. Any products manufactured prior to that time would have long ago been past there useful time.
Now, to answer your concern, any house built prior to 1960 most certainly has had lead based paint used on the exterior. Even so, this is not the cause of your problem. The cause is the amount of build-up of paint. This is what is causing the cracking and chipping of the coating.
The previous owner might have painted the house with an inferior "color" coating in order to sell the house and if this was done, it could have exacerbated to problem.
To be legally correct, I must refer you to the EPA website for lead renovations for the process required to remove any coatings on any house built prior to 1978.