A sunroom costs $22,000 to $75,000, with national averages of $47,000 to $55,000.13 Prefab kits start at $1,500 to $8,000 for the kit itself (HomeGuide); a four-season custom build reaches $80,000+.2 Prices below are national averages* for 2026.
*National averages, not local quotes. Your price depends on sunroom type (three-season vs four-season), size, foundation, HVAC, and finishes. Permits run $250 to $1,500 (Angi).1
$47,000
national average, Angi
$100 – $350
per sq ft, HomeGuide
$8,000 – $50,000
three-season, HomeGuide
$20,000 – $80,000
four-season, HomeGuide
Quick math: a 12×12 sunroom (144 sq ft) at Angi’s $150 to $300 per square foot = $21,600 to $43,200, matching its size table exactly, our arithmetic.1 Labor eats 40% to 60% of the total — $18,800 to $28,200 on Angi’s average job, its figures.1
Three-season vs four-season
| Type | HomeGuide total | Per sq ft (HG) | Angi total |
|---|---|---|---|
| Three-season room | $8,000 – $50,000 | $80 – $230 (custom) | $10,000 – $40,000 |
| Four-season room | $20,000 – $80,000 | $200 – $400 (custom) | $25,000 – $120,000 |
| Prefab sunroom | $5,000 – $30,000 (sun porch/prefab) | $20 – $150 (kit) | $6,000 – $40,000 |
Three-season rooms skip insulation and HVAC; four-season rooms are true year-round living space with heating and cooling, which is why the per-foot rate roughly doubles (HomeGuide).2
Conversion vs new addition (Fixr)
| Route | Per sq ft | Notes |
|---|---|---|
| Convert existing porch/patio/deck | $80 – $200 | Reuses the foundation; usually becomes a three-season room |
| New sunroom addition | $130 – $300 | New foundation and roof; typically four-season |
Fixr’s $10,000 low-end job is an 8×10 patio conversion; its $55,000 average is a 14×14 four-season addition (about $280 per square foot, our arithmetic).3
Cost by size
| Size | Angi | HomeGuide (3-season / 4-season) |
|---|---|---|
| 10×10 | $15,000 – $30,000 | $8,000 – $23,000 / $20,000 – $35,000 |
| 12×12 | $21,600 – $43,200 | $11,500 – $33,000 / $28,500 – $47,500 |
| 14×14 | $29,400 – $58,800 | $15,500 – $45,000 / $39,000 – $65,000 |
| 12×20 | $36,000 – $72,000 | $19,000 – $55,000 / $48,000 – $79,000 |
| 20×20 | $60,000 – $120,000 | $32,000 – $90,000 / $80,000 – $124,000 |
Angi’s bands sit between HomeGuide’s three- and four-season columns because its project pool mixes both types, our reading.12
Other sunroom styles (Angi)
| Style | Cost |
|---|---|
| Arizona room (screened) | $2,000 – $22,000 |
| Greenhouse | $6,000 – $10,000 |
| Conservatory | $6,000 – $80,000 |
| Solarium (all-glass) | $30,000 – $75,000 |
HomeGuide prices a glass solarium higher, $30,000 to $150,000, reflecting larger luxury builds in its data, our reading.2
Worked examples
Example 1 — 8×10 patio conversion, three-season. 80 sq ft x $80 to $200 = $6,400 to $16,000 (Fixr’s conversion rate), our arithmetic; Fixr’s $10,000 low-end job is exactly this.3
Example 2 — 10×12 three-season, custom. $9,500 to $27,500 (HomeGuide).2
Example 3 — 14×14 four-season addition (Fixr’s average). $55,000 (Fixr); HomeGuide’s four-season column says $39,000 to $65,000 for the same footprint.23
FAQ
Cheapest way to add a sunroom? Convert an existing porch or patio: $80 to $200 per square foot versus $130 to $300 for a new addition (Fixr).3
Is a prefab kit worth it? Kits run $1,500 to $8,000 (HomeGuide) plus assembly on an existing deck or patio — the budget route if your site already has a slab, our judgment.2
Three- or four-season? If you want year-round use and resale value as living space, four-season; for a fair-weather room, three-season saves roughly half the per-foot rate (HomeGuide), our judgment.2
Do I need a permit? Yes for additions: $250 to $1,500 (Angi), more with HVAC and electrical.1
Sunroom or full addition? A sunroom is glass-forward and usually cheaper per foot than a fully framed addition; compare our home addition cost guide, our judgment.
DIY shopping: sunroom and screen-room kits (plain link, no affiliate relationship) — prefab kits start in the $1,500-$8,000 band HomeGuide describes, assembled on an existing patio.
Sources
- Angi, How Much Does a Sunroom Addition Cost? (2026 data).
- HomeGuide, How Much Does a Sunroom Cost? (2026).
- Fixr, Sunroom Addition Cost
Related guides
Porch Cost
Greenhouse Cost (2026 Guide)
Screened-In Porch Cost
Home Sauna Cost
Home Addition Cost
Deck Cost
Patio Cost
All cost guides