Greenhouse Heating Efficiency: Insulation, Thermal Mass, and Programmable Control

First: Reduce Heat Loss (Best ROI)

• Bubble wrap insulation on inside of glass (water or spray adhesive).
• Polycarbonate glazing upgrade (double/triple wall) + bubble wrap inside.
• North wall removable insulation in winter.

Second: Add Thermal Mass

55-gallon water drums (black, sealed) — absorb solar heat by day, release at night. Low cost, high impact.

Third: Smart Temperature Management

• Programmable thermostat: Lower night temps (53°F weekends, 60°F weekdays).
• Zone heating if possible.

Real-World Example

My greenhouse (below zero winters): 4 ft below grade, polycarbonate + bubble wrap, water drums, programmable stat. Energy savings paid for upgrades in 3 years.

Resources

Charley's Greenhouse Supply (charleysgreenhouse.com) — insulation, polycarbonate, stats, drums.