The National Institute of Standards and Technology (NIST) uses microwave calorimeters to characterize power sensors, thereby measuring microwave power in a way that is traceable to the basic definitions of the SI units. Microcalorimeters measure microwave power that is dissipated as heat in a sensor. However, some of the microwave power is absorbed in the waveguide walls preceding the sensor. NIST accounts for this power absorption by defining a value called the correction coefficient. Therefore, to make traceable power measurements, it is important to study and quantify the correction coefficient. Another source of uncertainty comes from suspected variances in the connection repeatability. As parts of the calorimeter wear over time, they can affect results between experiments. Replacing these custom precision parts is expensive and time-consuming. In this talk we discuss the relationship between the correction factor and the isolation section width. Additionally, we designed a new microcalorimeter that incorporates all the key thermal functions of the original design and integrates more commercial components. By using more commercial components, we simplified the manufacturing process, reduced the cost, and incorporated precision connectors for improved connection repeatability. Finally, by creating a thermal simulation of a proposed WR-10 microcalorimeter design, we quantified the error and correction factor.