When installing a new furnace in an older home, there are several important considerations to keep in mind. First and foremost, the age of the home should be taken into account. Older homes may have wiring and other components that may not be compatible with modern furnaces. Additionally, it is important to check local building codes to ensure that any modifications to the home, such as altering gas lines or installing a new chimney, are done correctly and safely. The location of the furnace also needs to be taken into account; it should be placed in a place that is easily accessible so that regular maintenance can be performed. Lastly, the size of the furnace should match the size of the home to ensure that it can heat the entire space efficiently and cost-effectively.