The cost of owning HVAC equipment for the residential sector" has been much discussed by lending agencies, governmental authorities, utilities, and other interested parties. This paper discusses verifiably quantitative data gathered from service records of a heat pump maintenance contract program in operation since 1967 in Alabama. This report is especially significant since most service records are limited to the first five years of operation, while this report discusses finding for the first 10 years of operation. The major findings include:

1. There is a correlation between the cost of owning and reliability, which is evidenced through a 20% lower cumulative cost to service package heat pumps than split heat pumps at the end of year 5 and a 15% lower cumulative cost at the end of year 10.

2. The cost to service study revealed that the lowest cost to service brand had a total system median life of approximately 20 years in a range of 16 to greater than 20 (Lovvorn et al. 1985) and a compressor life expectancy in excess of 10 years (Lovvorn et al. 1986) with an extrapolated compressor median life of approximately 13.5 years.

3. The cost of maintaining a heat pump being marketed in the most current 10-year period in 1985 dollars is approximately $600, or $60 per year.

4. The service frequency of heat pumps in this study has decreased significantly over the past 20 years. In the most recent five-year period (1980-1985), approximately 50% of the units have required no service calls during the first five years after installation.