The blower fan on my 17 year old (80% efficient) Carrier gas furnace is
dead! I have 3 choices.

1. Replace the fan unit myself. Cost of fan unit? How difficult?

2. Hire an HVAC contractor to replace the fan unit. Cost estimates?

3. Hire an HVAC contractor to replace the entire furnace.

Is it worth replacing only the fan or shoiuld I replace the furnace? Any
advice? Any referals to an HVAC contractor in Milwaukee, WI area??

Thanks