Compare 2026 costs for 3-season vs. 4-season sunrooms, solariums, and screened porch conversions by square footage, framing material, Low-E glass, and foundation type.
In 2026, a 3-season sunroom costs $110 to $210 per square foot ($22,000 to $42,000 for 200 sq ft), while an insulated 4-season sunroom with Low-E double-pane glass and HVAC costs $185 to $340 per square foot ($37,000 to $68,000 for 200 sq ft). All-glass solariums range from $300 to $450/sq ft.
📐 Engineering Formula Used: Total Cost = (Length × Width × Sunroom Rate × Regional Multiplier) + Foundation + Mini-Split + Skylights
The table below provides verified 2026 material, labor, and installed turnkey cost ranges for sunroom addition cost calculator projects. Compare these figures alongside live industry benchmarks such as HomeAdditionCostCalculator.com ↗.
| Sunroom Type | Cost Per Sq Ft (2026) | 150 Sq Ft (10×15) | 224 Sq Ft (14×16) | Counted in Home Sq Ft? |
|---|---|---|---|---|
| Screened Porch Enclosure | $80 – $125 | $12,000 – $18,750 | $17,900 – $28,000 | No (Outdoor Living) |
| 3-Season Prefab Sunroom | $130 – $200 | $19,500 – $30,000 | $29,100 – $44,800 | Rarely (Unheated) |
| 4-Season Thermal Sunroom | $210 – $330 | $31,500 – $49,500 | $47,000 – $73,900 | Yes (If Heated Year-Round) |
| All-Glass Solarium / Conservatory | $300 – $450 | $45,000 – $67,500 | $67,200 – $100,800 | Yes (If Climate Controlled) |
Project Scenario: 16 ft × 14 ft (224 sq ft) 4-Season Sunroom with New Insulated Slab & Mini-Split HVAC
| Itemized Quote Line Item | 2026 Estimated Cost |
|---|---|
| 224 sq ft 4-Season Thermal Aluminum/Vinyl Frame & Low-E Glass (@ $235/sq ft) | $52,640 |
| New Frost-Protected Concrete Slab Foundation | $6,200 |
| 12,000 BTU Ductless Mini-Split Heat Pump & Electrical Circuit | $3,800 |
| Estimated Total 4-Season Sunroom Cost | $62,640 ($279.64/sq ft) |
To count toward your home’s official gross living area (GLA) on an appraisal, a sunroom must be built on a permanent foundation, feature thermally broken frames with double-pane Low-E glass, and have a permanent heating/cooling source capable of maintaining 68°F year-round.
Because a sunroom has 60% to 80% glass wall area, its solar heat gain and winter heat loss differ drastically from standard drywall rooms. Installing an independent ductless mini-split prevents your main home furnace and AC from short-cycling.
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