Existing Patio/Deck
New Concrete Slab
Raised Crawl Space
Standard Single Pane / Basic Vinyl
Double Pane / Energy Star Rated
High-Performance Low-E / Premium Aluminum
Estimated Investment Range
Understanding Sunroom Construction Costs
Adding a sunroom is one of the most effective ways to increase your home's square footage while inviting natural light and nature indoors. However, prices vary wildly based on whether you want a simple screened-in porch or a fully climate-controlled four-season addition.
Major Factors Influencing Your Budget
Sunroom Type: A three-season room lacks the heavy insulation and HVAC connection of a four-season room, making it significantly cheaper but unusable during extreme winters.
Foundation Requirements: Building on an existing reinforced concrete patio is the most affordable route. If a new foundation or crawl space must be excavated and poured, costs increase by $5,000 to $15,000.
Glass Quality: Since sunrooms are primarily glass, the thermal efficiency of the panes is the biggest driver of long-term comfort and upfront cost.
Permits and Labor: Electrical wiring, HVAC ductwork, and local building permits typically account for 25% to 35% of the total project cost.
Sunroom Cost Comparison Table
Room Type
Avg. Cost Per Sq. Ft.
Typical Use Case
Screen Room
$25 – $50
Bug protection, summer breeze
Three-Season
$80 – $230
Spring through Autumn usage
Four-Season
$200 – $400+
Year-round living space
Solarium
$300 – $600
Maximum light, glass roof
Real-World Project Examples
Example 1: The Suburban Update
A 12×12 (144 sq. ft.) Three-Season room built on an existing deck with standard double-pane glass typically ranges between $22,000 and $28,000 depending on local labor rates.
Example 2: The Luxury Addition
A 15×20 (300 sq. ft.) Four-Season room requiring a new concrete slab foundation and high-efficiency Low-E glass can easily reach $85,000 to $110,000 as it functions as a true home addition.
function calculateSunroomPrice() {
var length = parseFloat(document.getElementById('roomLength').value);
var width = parseFloat(document.getElementById('roomWidth').value);
var typeCost = parseFloat(document.getElementById('sunroomType').value);
var foundationCost = parseFloat(document.getElementById('foundationType').value);
var materialMultiplier = parseFloat(document.getElementById('materialGrade').value);
var resultArea = document.getElementById('resultArea');
var totalCostDiv = document.getElementById('totalCost');
var breakdownDiv = document.getElementById('costBreakdown');
if (isNaN(length) || isNaN(width) || length <= 0 || width <= 0) {
alert("Please enter valid positive numbers for length and width.");
return;
}
var area = length * width;
// Logic: (Base Type + Foundation) * Area * Material Multiplier
var basePrice = (typeCost + foundationCost) * area * materialMultiplier;
// Add 15% for miscellaneous (permits, electrical, finishing)
var lowEstimate = basePrice * 0.9;
var highEstimate = basePrice * 1.15;
resultArea.style.display = 'block';
totalCostDiv.innerHTML = '$' + lowEstimate.toLocaleString(undefined, {maximumFractionDigits: 0}) + " – $" + highEstimate.toLocaleString(undefined, {maximumFractionDigits: 0});
breakdownDiv.innerHTML = "Based on " + area + " sq. ft. at an adjusted rate of approx. $" + (basePrice / area).toFixed(2) + " per sq. ft. (including foundation and materials).";
// Scroll to result
resultArea.scrollIntoView({ behavior: 'smooth', block: 'nearest' });
}