Budget tiers

External windshield/cab covers, temperature/humidity sensors, seal repair, strategic reflective/insulation workand better fan placement. Often the best first dollars.

Stage 2: $300-$1,500

Multiple quality circulation fans, awning/shade, improved cab partition/insulation, wiring and monitoring. Pricingdepends heavily on fabrication.

Stage 3: $1,500-$6,000+

12/24 V A/C, structural installation, refrigerant work, heavy DC electrical integration and condensate/weathersealing. Battery/charging upgrades can exceed the A/C cost.

Order matters

Measure -> stop solar -> fix envelope -> design airflow -> calculate energy -> select A/C -> integrate safely ->commission. Do not spend the budget in reverse.

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.