The compressor is often considered the "heart" of a vapor compression air-conditioning system, and is also typically the largest consumer of energy within a home setting. From this designation, the selection of compressor type holds significant influence within its operational environment, including energy consumption, ease of maintenance, and generally of primary concern for a homeowner, cost. While a variable speed compressor offers greater potential for energy savings, the increase in first-cost expense should be justified by its corresponding energy savings. This paper studies the employment of both a fixed and variable speed compressor operating inside a heat pump within a residential setting. Electrical and thermal data were collected via circuit monitors and thermocouples, respectively, and observed over a wide range of ambient conditions and time periods. The home under observation is a 2-story design, constructed in the 1920’s, and houses three graduate students. Data gathered in this setting is normalized against multiple parameters, and compared to real energy, cost, and overall efficiency improvements.