Sunroom Cost Calculator
Estimated cost of a sunroom addition by type and size.
Updated · How we check our maths
- Estimated cost
- $14,500 – $41,650
- Sunroom (168 sq ft)
- $13,440 – $38,640
- Foundation
- $840 – $2,520
- Permits
- $200 – $500
Quick answer
Sunrooms typically cost $100–$350 per square foot: prefab kits $20–$150, three-season rooms $80–$230, four-season rooms $200–$400 and solariums $300–$800 per sq ft. A 12 × 14 three-season room usually costs about $14,000–$41,000 with a new foundation.
What the Sunroom Cost Calculator does
Enter the size and choose the type of room. Three-season rooms aren't heated or insulated for winter; four-season rooms are fully insulated and conditioned, so they cost more and usually need a mini split. The calculator adds foundation, HVAC and permit costs, and adjusts for high-cost states.
The formula
Cost = area × price per sq ft (by type) + foundation ($5–$15/sq ft) + HVAC (four-season) + permits.
Worked example
15 × 15 four-season room on a new foundation: 225 × $200–$400 + $1,125–$3,375 + $2,000–$6,000 + permits = about $48,300–$99,900.
How to use the Sunroom Cost Calculator
- Enter the room's width and depth.
- Choose the sunroom type.
- Say whether you need a new foundation and pick your price level.
Frequently asked questions
What's the difference between a three- and four-season room?
A four-season room is insulated and heated/cooled for year-round use; a three-season room is for spring to autumn.
Does a sunroom add value?
It can, especially four-season rooms that count as living space, but rarely recovers its full cost.
Do I need a permit for a sunroom?
Almost always, because it is a structural addition.
Results are estimates for planning and learning. Check important figures with a qualified professional. How we build and check our calculators.