Final answer:
Close all external doors and windows, open all interior doors, turn off HVAC systems, and set the thermostat to a normal level to properly prepare for a blower door test.
Step-by-step explanation:
To prepare a house for the blower door test, all external doors and windows should be closed to ensure that the house is sealed properly. This helps in accurately measuring the air leakage of the house. All interior doors should be open to allow air to flow freely throughout the house during the test. However, the HVAC systems should be turned off to prevent any interference with the test results. The thermostat should be set to a normal level to avoid any extreme temperature differences that could affect the measurements. Remember, the goal of the test is to identify air leaks, so creating a controlled environment is crucial for an accurate assessment.