Layer 1: external window covers

Why exterior wins

An interior cover acts after solar energy has crossed the glass. It can reduce heat moving deeper into the vanbut leaves very hot glass and trapped heat at the window. An exterior reflective cover intercepts the sun beforethat greenhouse step.

Our test

With interior covers, the windshield/glass became too hot to touch. After fitting the exterior cover and waitingabout 30 minutes in similar sun, the glass felt dramatically cooler.

Fit matters

Cover windshield and cab side glass with minimal gaps, secure for wind, avoid scratching paint/glass and neverobstruct the vehicle when driving. Reflective material must tolerate UV, rain and local wind.

Affiliate products

External windshield cover: choose the correct van model. Reflective insulation: product link. Verify size, firebehavior and installation instructions.

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.