Chapter 4 of 67% of exam
Solar Thermal Installation
Solar thermal is 7 percent of the examination: solar water heating and solar pool heating. The PrepPass CSLB C-46 Solar Study Guide covers this area in depth, with worked examples and a chapter quiz.
Water heating systems
Active systems pump; passive systems do not. Direct systems heat potable water; indirect systems use a heat-transfer fluid.
Freeze climates
Indirect systems with non-toxic propylene glycol; ethylene glycol must not be used.
DOE Energy Saver pages (archived)Heat exchangers
Double walls with drainage and leak detection when the fluid is toxic.
DOE Energy Saver pages (archived)Certification
Solar water and pool heating equipment must be certified by an accredited listing agency.
Government Code 65850.5Pool heating
Filtered pool water is diverted through collectors when they are warmer than the pool.
Collector area
50–100% of the pool's surface area; less with a pool cover.
DOE Energy Saver, Solar Swimming Pool Heaters (archived)Pool volume
Cubic feet × about 7.48 gallons per cubic foot.
NIST Handbook 44, Appendix CHeat
Btu = gallons × 8.35 × temperature rise.
DOE Energy Saver (archived)Keep going: the full CSLB C-46 Solar guide covers every section of the exam. CSLB C-46 Solar Trade Exam Study Guide (2026) — PDF + EPUB, $24.99 · 14-day refund →
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