Choose capacity for the house.

Start with a load calculation

A load calculation considers the building, insulation, windows and design conditions. It estimates how much heating and cooling the house needs. Ask how the proposed capacity was selected.

Check the ducts as well

The system must move enough air through the existing ducts. A larger unit is not a substitute for correcting a duct restriction or an airflow problem.

Review cold-weather capacity

For a heat pump, compare the home’s heating demand with the model’s delivered capacity at cold temperatures. Nominal capacity alone does not explain winter performance.

Describe the rooms that bother you

Tell us about rooms that stay hot or cold and any additions to the house. Those details help focus the assessment. Start your estimate.