sunroom

Cost Difference: Fully Insulated Sunroom vs Non-Insulated (2026 Data)

Cost Difference: Fully Insulated Sunroom vs Non-Insulated (2026 Data) A fully insulated four-season sunroom costs $200-$400 per square foot installed in 2026, while a non-insulated three-season room costs $80-$230 per square foot -- a difference of roughly $120-$170 per square foot, or $24,000-$34,000 more on a typical 200-square-foot build. The insulated version adds framed-and-insulated walls, double-pane low-E glass, an insulated roof, and an HVAC tie-in. The non-insulated version is glass walls on a frame with no climate control. Use the Sunroom Addition Cost Calculator(/construction/sunroom-addition-cost-calculator) to price your own footprint before you read on. On the last sunroom I scoped, a homeowner asked me why two bids on the "same" 14-by-14 room came in at $26,000 and $61,000. The answer was insulation. The cheap bid was a three-season shell at about $130 per square foot; the expensive one was a fully insulated four-season build at about $310 per square foot. That...