Quick answer: HomeGuide puts a US sunroom at $100–$350 per square foot on average: $15,000–$50,000 for a custom three-season room, $20,000–$80,000 for a four-season room and $50,000–$150,000 for a glass conservatory addition. Angi’s figures, as reported by HomeLight, are $10,000–$40,000 for a three-season room and $25,000–$120,000 for a four-season room. City permit and plan review fees come on top, from a few hundred to over a thousand dollars.
Sunroom cost checker
Pick a project to see the reported US price range and where the figure comes from. It is a guide, not a quote.
Prices change and depend on the size of the job, the property, access and location. Figures were last checked . Always get a written quote before work starts.
Request a free quoteSunroom, four-season room or conservatory?
In the US, what the British call a conservatory is usually sold as a sunroom. The words matter because they change the price:
- Screen room or patio enclosure: an existing patio or deck enclosed with screens or lightweight panels; usually no insulation, heating or electrics.
- Three-season room: glazed walls on a foundation, but typically without insulation or heating and cooling, so it is too cold or too hot for part of the year.
- Four-season or all-season room: insulated, with better glazing, and heated and cooled, usually from the house system, so it works as living space year round.
- Solarium or conservatory: a four-season room with a glass roof as well as glass walls; the most expensive option. In the Southwest an enclosed patio is sometimes called an Arizona room.
Every type that is enclosed and attached to the house normally needs a building permit. See our guide to sunroom permits in the USA.
Sunroom prices by type
These are reported typical ranges for supply and installation, not quotes.
| Type | Reported cost | What it usually includes |
|---|---|---|
| Prefab sunroom kit | $1,500–$8,000 | Kit assembled on an existing deck or patio |
| Enclosed patio or screened-in porch | $8,000–$30,000 | Built on an existing deck or patio; usually no insulation, HVAC or electrics |
| Prefabricated sunroom (brand dealer) | $5,000–$50,000 | Insulated panels available; three- or four-season models |
| Custom three-season room | $15,000–$50,000 | Built on a foundation; insulated and sealed but usually no HVAC |
| Four-season room | $20,000–$80,000 | Foundation, insulation, electrics and HVAC |
| Glass solarium | $30,000–$100,000 | Glass walls and roof |
| Conservatory addition | $50,000–$150,000 | Glass-roofed four-season room with foundation, insulation, electrics and HVAC |
Source: How Much Does a Sunroom Cost? (homeguide.com, written August 2025). Checked September 2026.
Prices by size and per square foot
| Size | Three-season room | Four-season room |
|---|---|---|
| 10 ft x 10 ft | $8,000–$23,000 | $20,000–$35,000 |
| 12 ft x 12 ft | $11,500–$33,000 | $28,500–$47,500 |
| 12 ft x 16 ft | $15,500–$45,000 | $38,500–$63,500 |
| 16 ft x 16 ft | $20,000–$60,000 | $50,000–$80,000 |
| Per square foot, custom build | $80–$230 | $200–$400 |
Source: HomeGuide, as above. HomeGuide prices a conservatory at $200–$600 per square foot and notes that high-cost states such as New York, New Jersey, Massachusetts, Florida and California can raise prices by up to 50%. Checked September 2026.
A second source gives a similar picture: HomeLight, citing Angi, reports $10,000–$40,000 for a three-season room ($150–$300 per square foot), $25,000–$120,000 for a four-season room and $250–$1,500 for the building permit (Sunroom Costs, homelight.com, June 2026). HomeGuide’s own permit estimate is $200–$500, plus possible zoning, electrical and HVAC permits.
Official fees in five big cities
Permit fees are set by each city, not by installers, and are extra unless your quote includes them. What we found for a typical sunroom addition on a house:
| City | Building permit basis | Example or minimum | Historic review |
|---|---|---|---|
| New York City (DOB) | $130 for the first $5,000 plus $2.60 per extra $1,000 (1–3 family) | $221 on a $40,000 job | LPC permit in 157 historic districts |
| Los Angeles (LADBS) | Valuation table plus plan check at 90% | About $779 on a $40,000 job, before surcharges | HPOZ review in 35 overlay zones |
| Chicago (DOB) | Floor area x construction and scope factors | $900 minimum for an addition to a 1–3 unit building | Commission on Chicago Landmarks reviews the permit |
| Houston (Permitting Center) | City fee schedule and calculator | Floodplain development permit $402.84 if in the floodplain | COA $302.93 in 23 historic districts |
| Phoenix (PDD) | Valuation table plus plan review at 80–100% | About $1,206 on a $40,000 job | CNE or COA in 36 residential districts |
Sources: each city’s published fee schedule, listed on the city pages. Examples are our arithmetic from those schedules. Checked September 2026.
Energy codes and why they change the price
Most US cities use a version of the International Energy Conservation Code (IECC); California uses its own Title 24 standards. Under the IECC, a heated or cooled sunroom must meet the same insulation rules as the house unless it is thermally isolated, meaning separated from the house by exterior-grade walls, doors or windows. A thermally isolated sunroom gets lighter rules: at least R-19 ceiling insulation in climate zones up to 4 and R-24 in zones 5 to 8, R-13 walls everywhere, with the dividing wall meeting the full rules. That is one reason a four-season room in Chicago (zone 5A) costs more than a three-season room in Houston (2A) or Phoenix (2B). See heating a conservatory.
Checking the contractor
Licensing is set by each state and sometimes each city. California requires a CSLB licence for jobs of $1,000 or more, Arizona requires a Registrar of Contractors licence for work that needs a permit, New York City requires a DCWP Home Improvement Contractor licence for jobs over $200, Chicago requires a City general contractor licence, and Texas has no state licence for general contractors but licenses electricians and air-conditioning contractors. Our city guides explain each check.
FAQs
How much does a sunroom cost in the US?
HomeGuide reports $100–$350 per square foot on average, with custom three-season rooms at $15,000–$50,000 and four-season rooms at $20,000–$80,000.
Is a conservatory the same as a sunroom?
A conservatory is a type of sunroom with a glass roof as well as glass walls, built as a four-season room. HomeGuide puts a conservatory addition at $50,000–$150,000.
Do I need a permit for a sunroom?
Almost always, if it is enclosed and attached to the house. Permit fees vary by city, from about $221 in New York City to about $1,206 in Phoenix for a $40,000 job on the schedules we checked.
Is a three-season room cheaper to run?
It is cheaper to build because it has no heating or cooling, but you cannot use it comfortably all year. Adding heating later can mean upgrading insulation and glazing to meet the energy code.
Why do quotes vary so much?
Size, foundation, glass type, roof type, heating and cooling, and local labour costs. Our guide to comparing quotes explains what to line up.
Local guides
- Sunrooms in New York City
- Sunrooms in Los Angeles
- Sunrooms in Chicago
- Sunrooms in Houston
- Sunrooms in Phoenix
Sources
- How Much Does a Sunroom Cost? (homeguide.com)
- Sunroom Costs (homelight.com), citing Angi cost data
- NYC Department of Buildings fee notices (nyc.gov)
- City of Los Angeles Housing Element Appendix 2.4, building permit fees (planning.lacity.gov)
- Building Permit Fee Tables effective January 6, 2026 (chicago.gov)
- City-Wide Fee Schedule (cohweb.houstontx.gov)
- PDD Fee Schedule, effective 1/20/2026 (phoenix.gov)
- International Energy Conservation Code, section R402.2.13 Sunroom insulation (up.codes)
Last checked: September 2026. Prices and fees change, so treat these as a guide and confirm with installers and your city.
Compare Conservatories is a comparison and referral service, not a sunroom or conservatory installer. We do not design, build or approve sunrooms, and a listing here is not a recommendation.