Some builders try to save money by installing their own warm-air furnaces, and some do a decent job. But more often than not, I end up talking to their frustrated customers a couple years later, when they're ready to rip out a practically new furnace. Whether you're replacing a wornout furnace or just need to add a few duct runs for an addition, if your clients can't sit in the new family room without freezing, or can't pay the heat bill, they're not going to be happy with you. Scope Out the Job Before you can recommend a specific furnace, you have to know what will and won't work with the job
