Sunroom Cost Calculator
Three-season or four-season sunroom build cost.
Enter your values
Enter the length in ft.
Enter the width in ft.
Choose one of: Screened porch, Three-season, Four-season insulated, Conservatory / custom.
Choose one of: Existing deck or slab, New concrete slab, Crawl space / footings.
Enter the hvac add-on in $.
Results update instantly as you type — no submit needed. Your values are remembered on this device, and the shareable link reopens the calculator with exactly these numbers.
- Estimated total
- $37,100.00
- Room size
- 192 sq ft
- Structure & glazing
- $28,800.00
- Foundation
- $4,800.00
- Heating & cooling
- $3,500.00
- Cost per sq ft
- $193.23
Quick answer
Sunrooms cost roughly $80–200 per square foot: three-season kits at the low end and insulated four-season rooms with HVAC at the top.
cost = area × rate + foundation + HVAC
At a glance
| What it does | Three-season or four-season sunroom build cost. |
|---|---|
| Category | Home & DIY |
| Inputs needed | Length, Width, Sunroom type, Foundation, HVAC add-on |
| Main output | Estimated total |
| Formula | cost = area × rate + foundation + HVAC |
| Cost | Free — no sign-up, no download |
How to use the Sunroom Cost Calculator
- 1Enter the planned room footprint.
- 2Choose the sunroom type — screened through to full conservatory.
- 3Pick the foundation and add HVAC for year-round use.
Inputs explained
- Length(ft)
- Enter the length in ft.
- Width(ft)
- Enter the width in ft.
- Sunroom type
- Choose one of: Screened porch, Three-season, Four-season insulated, Conservatory / custom.
- Foundation
- Choose one of: Existing deck or slab, New concrete slab, Crawl space / footings.
- HVAC add-on($)
- Enter the hvac add-on in $.
Worked example
Using the values the calculator loads with:
Inputs
- Length16 ft
- Width12 ft
- Sunroom typeFour-season insulated
- FoundationNew concrete slab
- HVAC add-on3500 $
Results
- Estimated total$37,100.00
- Room size192 sq ft
- Structure & glazing$28,800.00
- Foundation$4,800.00
- Heating & cooling$3,500.00
- Cost per sq ft$193.23
Frequently asked questions
How much does a 12x16 sunroom cost?
About $25,000–35,000 for a four-season insulated room on a new slab, or $15,000 for a three-season build.
Does a sunroom add home value?
A four-season room typically returns 45–60% of its cost at resale and much more in usable living space.
What do I need to enter into the Sunroom Cost Calculator?
Just 5 values: length, width, sunroom type, foundation, hvac add-on. Every field starts with a realistic example, so you can change one number at a time and watch the result update instantly.
How does the Sunroom Cost Calculator work out the answer?
Sunrooms cost roughly $80–200 per square foot: three-season kits at the low end and insulated four-season rooms with HVAC at the top. It applies the formula cost = area × rate + foundation + HVAC and shows the working so you can check each step by hand.
Is the Sunroom Cost Calculator free, and do I need an account?
It is completely free with no sign-up, no download and no usage limit. Everything is calculated in your browser, so the numbers you type never leave your device.
Results are estimates for general information. For medical, legal, structural or financial decisions, confirm with a qualified professional.