Measure before buying

Record the real problem

Log outdoor shade temperature, interior front/middle/rear temperatures, relative humidity, sun exposure,parking direction, A/C mode, electrical power and door openings. Measure at seated/dog height, away fromdirect sun and supply-air blast.

Find hot surfaces

Use an infrared thermometer or thermal camera carefully: shiny metal/glass can give misleading readings.Compare similar matte/taped spots to locate windshield, forehead, roof rib, door and floor hot zones.

Test one change

Hold weather and operating mode as constant as possible. Compare external vs internal cover, awning vs noawning, each fan combination and A/C power. A 30-minute snapshot is useful; several hours show heat soakand battery reality.

Define success

Choose targets for occupied comfort, sleeping, working and safe shutdown. Do not use one thermostat readingas proof that every zone is safe.

System rule

Do not judge a cooling upgrade at the vent. Judge it by the hottest occupied zone, humidity, energy usedand whether the system can recover that energy safely.

CHAPTER CHECK

• I can explain which heat path this step addresses.• I measured its effect at front, middle and rear - not only by touch.• I added its power, failure mode, maintenance and safety action to the system plan.