What is one advantage of an active solar heating system over a passive system?

• A. It's cheaper
• B. It's more compact
• C. Requires less maintenance
• D. Uses less energy

Answer: (B)

Active solar heating moves heat with pumps or fans and uses controls to deliver heat where it’s needed. Because heat can be transferred quickly and efficiently through pipes or ducts, you can design a smaller, modular collector system and still meet the heating load. The heat doesn’t have to rely on large architectural features or extensive thermal mass built into the home, so the overall setup can take up less space and be placed closer to the area being heated. That compact, flexible arrangement is the main reason this option is considered an advantage over passive designs, which depend on building mass, large glazing areas, or sunspaces that can take up more room.

The other ideas—being cheaper, requiring less maintenance, or using less energy—aren’t inherent advantages of active systems. They often involve trade-offs: active systems add pumps and controls that raise cost and maintenance, and energy use depends on usage and design rather than being automatically lower.