Which sunroom is right for your home comes down to how much of the year you’ll really use it. In other parts of the country, the goal is to stay warm in the winter. But in the Atlanta area, summer’s heat and humidity can make a room with no insulation or air conditioning feel hotter inside than your open patio on a July afternoon.
Two options can help you create an additional space to enjoy, depending on your goals and budget. A four-season sunroom is insulated and tied into heating and cooling, so it works as year-round living space. A three-season sunroom is not insulated or climate controlled but built the mild months, which keeps it simpler and less expensive.
This guide covers how each option is built, how Georgia’s climate should steer your decision, and what each one costs, so you can decide which build fits your home before you call a contractor.
Find Out Which Sunroom Fits the Way You Live
At Perimeter Remodeling, we’ve helped homeowners plan outdoor living spaces since 1999, and we’ll tell you straight whether a year-round sunroom makes sense for your home. Schedule your free consultation or call 770-333-8174 to get started.
How Three-Season and Four-Season Sunrooms Are Built Differently
The core difference between a three-season and a four-season sunroom is climate control. A four-season sunroom is insulated and tied into heating and cooling for year-round use, while a three-season sunroom has neither and is built for the mild months.
Both rooms give you walls, a roof overhead, and shelter from rain, wind, bugs, and pollen. What separates them is the framing, the glass, the insulation, and whether the room can control its own temperature. Here is how the two builds compare, point by point.
Three-Season Sunroom
- Usage – A three-season sunroom is built for spring, fall, and mild days. In the Atlanta area it stays comfortable most of the year, but without added heating or cooling, it gets hot at the peak of summer and cold in the coldest stretches of winter.
- Construction – A three-season sunroom uses basic wood framing and is usually built on top of an existing patio or deck.
- Insulation – A three-season sunroom has no wall, floor, or roof insulation, so the room tracks the outdoor temperature.
- Climate Control – A three-season sunroom relies on natural airflow, ceiling fans, or a portable heater rather than a permanent heating and cooling system.
- Cost – A three-season sunroom is the more affordable build. In the Atlanta area, a 10×10 starts around $10,000.
Four-Season Sunroom
- Usage – A four-season sunroom is built for year-round use. It stays comfortable through Atlanta’s hot, humid summers and its cold winter snaps, so you can use it as everyday living space in any month.
- Construction – A four-season sunroom uses insulated framing paired with double-pane or Low-E glass and a proper foundation built to support the room.
- Insulation – A four-season sunroom is fully insulated in the floor, walls, and roof, built to the same standards as the rest of your house.
- Climate Control – A four-season sunroom ties into your home’s central HVAC system or uses a dedicated ductless mini-split to heat and cool the space.
- Cost – A four-season sunroom costs more because of the added insulation, glass, foundation, and climate control. In the Atlanta area, a 10×10 starts around $25,000.
That extra construction also means extra inspections. A four-season build adds electrical and mechanical work, and each piece gets checked by the county before the room is finished.
How Georgia’s Climate Changes the Decision
The name “three-season” assumes the season you give up is winter. In Atlanta, the season that tests the room hardest is summer.
NOAA’s Georgia climate summary describes the state’s summers as long, hot, and humid, with winters that are short and usually mild. Atlanta actually sees fewer extreme-heat days than inland Georgia, averaging about 7 days a year above 95°F compared to roughly 20 in cities like Macon and Columbus. That milder outdoor picture is exactly why homeowners assume a three-season room will stay comfortable all summer.
The catch is the room itself: a space with no insulation or air conditioning traps heat, so on a sunny afternoon it can feel hotter inside than your open patio even when the outdoor temperature is only in the upper 80s.
Winter is the easier problem here. Cold snaps tend to be short, so a four-season room doesn’t have to work hard to stay warm, and a three-season room still offers some pleasant, sunny afternoons in December and January.
Spring and fall are where both rooms shine. Windows and walls keep out the heavy spring pollen and the pop-up storms, and the temperature outside stays comfortable enough that a three-season room feels just right.
If you go four-season, the glass matters as much as the mini-split. The U.S. Department of Energy recommends glass with a low solar heat gain coefficient (SHGC) in warm climates to cut the heat coming through the windows, so ask what SHGC rating comes with the glass in your quote. Our guide to energy-efficient upgrades for four-season sunrooms covers more ways to keep the room comfortable.
Pro Tip: Check which direction the room will face before you decide. A west-facing sunroom takes the low, hot afternoon sun during the warmest part of a summer day, which pushes the decision toward four-season, while an east-facing room gets gentler morning light and stays more comfortable without climate control.
Pros and Cons of Each Sunroom Type
Below are some guidelines to consider when deciding which sunroom is right for you.
Three-Season Sunroom
Pros:
- Lower starting price – A 10×10 starts at $10,000, well under half the cost of a four-season room the same size.
- Uses what you already have – These rooms are usually built on an existing patio or deck, which keeps the project simpler.
- Shelter without the climate package – You still get protection from rain, wind, bugs, and pollen.
- No added heating or cooling bills – With no system to run, the room adds nothing to your heating and cooling costs.
Cons:
- Hot summer afternoons – Without insulation or air conditioning, the room gets uncomfortable at the peak of summer, especially if it faces west.
- Cold mornings and nights – In winter, the room tracks the outdoor temperature.
- Usually not counted as living area – Appraisers generally count only finished space with permanent heating, so a three-season room typically won’t add to your home’s official square footage.
- Limited everyday use – It’s hard to rely on as an office or family room in every season.
Four-Season Sunroom
Pros:
- Comfortable every month – Insulated framing, upgraded glass, and climate control let you use the room in August and January alike.
- A true room addition – It works as a home office, family room, or breakfast nook you use every day.
- Can count as living area – A permitted, finished room with permanent heating typically counts toward your home’s square footage, which matters for appraisals and insurance.
- Glass that protects your furnishings – Low-E glass cuts heat gain and blocks much of the UV light that fades floors and furniture.
Cons:
- Higher upfront investment – It starts at $25,000 for a 10×10, and a 14×14 typically runs $40,000 to $65,000 or more.
- A longer, more involved build – The foundation, electrical, and HVAC work add trades and inspections to the schedule.
- Ongoing energy costs – You’re heating and cooling another room, though a mini-split lets you run it only when you’re using the space.
- Paying for comfort you might not use – If you’d realistically only use the room on mild days, you’re paying for climate control that will sit idle.
Which Sunroom Fits Your Household?
The right choice comes down to your routine. Consider how many months a year you’ll realistically use the space, what you’ll use the space for, who will use it, and at what time of day.
Sometimes that conversation leads to a simpler room than you planned. Other times it leads to a bigger investment that fits your life better.
Sunrooms for Spring and Fall Entertaining
If you host friends on mild evenings, grill on weekends in April and October, and head indoors when it gets hot, a three-season sunroom might be just the ticket. It gives you a sheltered, bug-free space for exactly the months you’d use it, at a much lower starting price.
Best for: homeowners who want an enclosed gathering space for the mild months and don’t plan to use it in July or January.
Sunrooms for Homeowners with a Solid Patio or Deck
If you already have a patio or deck in good shape, a three-season room can usually be built on top of it. That keeps the project simpler and the investment lower while still giving you a functional room.
Best for: homeowners who want more use out of an existing outdoor space without starting from the ground up.
Sunrooms for Work-From-Home Households
If the sunroom will be your office, the math changes. You need a room that’s comfortable at 2 p.m. in August and 8 a.m. in January, which means insulation, upgraded glass, and a dedicated heating and cooling source.
Best for: anyone planning to use the room every weekday, year-round.
Sunrooms for Homeowners who Want to Increase Home Value
If you plan to stay in your home for years and want the addition to count as living area, a permitted four-season room is the stronger choice. It functions as a true room addition, and it’s the version appraisers usually treat as part of the house.
Best for: homeowners who want a room that adds everyday living space and counts toward the home’s square footage.
If you mainly want fresh air and bug-free evenings, a screen room might fit better than either sunroom. Our screen room vs. three-season room comparison walks through that decision.
Three-Season vs. Four-Season Sunroom Cost in Atlanta
Once you know which room fits, here’s where our sunroom builds start.
- 10×10 three-season – Starts at $10,000 for an enclosed room without insulation or climate control.
- 10×10 four-season – Starts at $25,000 with insulated framing, upgraded glass, and year-round heating and cooling.
- 14×14 three-season – Typically runs $30,000 to $40,000.
- 14×14 four-season – Typically runs $40,000 to $65,000 or more, depending on the glass, finishes, and heating and cooling setup.
- 14×14 high-end or custom – Starts around $65,000, usually architect-designed with premium materials and finishes.
For a closer look at the smallest size, see our 10×10 sunroom cost guide for Atlanta.
What Drives the Price Gap
The difference between the two builds comes from a handful of specific line items.
- Heating and cooling – HVAC integration typically starts around $3,500. ⚠️
- Electrical – Each electrical drop for outlets, lighting, or a ceiling fan runs about $250 to $350, on either type of room.
- Foundation – A proper foundation adds cost to a four-season build, while a three-season room can often use the patio or deck you already have.
- Glass – The double-pane or Low-E glass package costs more up front, and it’s the reason a four-season room stays comfortable.
- Site prep – Preparing the site starts around $750, depending on your yard.
Costs vary with your home’s structure, site conditions, the finishes you choose, and county permit requirements, so treat these numbers as starting points rather than a quote.
If the four-season number is what’s holding you back, financing can spread it out. Options include 0% interest for 12 months, zero down payment, and a 9.99% fixed rate for 180 months, with monthly payments as low as $129.
How Each Sunroom Affects Your Home’s Value
A four-season sunroom usually counts toward your home’s heated square footage, and a three-season room usually does not. That single difference is the biggest resale gap between the two.
A four-season sunroom often qualifies as living space. Because it’s permitted, insulated, and climate-controlled, it can raise your home’s appraised size and value, and it gives you documented, code-compliant square footage that supports a stronger resale. Appraisers generally count finished, above-grade space with permanent heating as living area, which is the standard a four-season room is built to meet.
A three-season sunroom usually doesn’t add heated square footage, because it has no permanent climate control. It still adds usable, appealing space that can help a sale, but it’s typically valued as a porch or bonus area rather than finished living space.
That square footage only counts when the room is permitted and finished, so the permit does more than satisfy the county. It’s what lets the space show up as living area when your home is appraised or sold.
What a Low Sunroom Quote Usually Leaves Out
You’ll see sunroom prices online, and in some quotes, that sit well below the numbers above. Those low numbers usually come from unlicensed one-person operations that skip permits and inspections, cut corners on footings, or call a room four-season without the insulation and glass to back it up.
Our pricing reflects code-compliant footings, quality materials, pulled permits, and scheduled inspections. Before you sign with any contractor, check for these:
- Pulled permits – We pull every permit on every project. If a contractor offers to skip the permit to save you money, don’t let them talk you out of it.
- Believable permit fees – A quote of $3,000 to $4,000 just for the permit can be a sign the contractor isn’t licensed and is paying to use someone else’s license.
- A real climate package – A “four-season” room without insulated framing, double-pane or Low-E glass, and a permanent heating and cooling source is a three-season room at a four-season price.
- Progress-based payments – Payments should follow completed work instead of a large lump sum up front. At Perimeter Remodeling, the number of payments matches the number of weeks your build takes.
- A written craftsmanship warranty – The industry standard is often just 12 months. Our 36-month craftsmanship warranty covers three times that.
Cheap quotes tend to cost more later, through failed inspections, a room that doesn’t hold up, or a denied insurance claim. If a tree comes down on a sunroom that was never permitted, your insurer may refuse to pay for the damage.
Build the Right Sunroom With Perimeter Remodeling
The three-season vs. four-season sunroom decision comes down to how you’ll use the room, which way it faces, and how much of the year you want to spend in it. Get those answers right, and either room can be a smart investment.
Perimeter Remodeling has served Atlanta homeowners as a licensed general contractor since 1999, and all of our contractors have been working with us for a minimum of 10+ years. You’ll work with the same sales rep from your first estimate through the final walkthrough.
We’ll measure your space, talk through how you plan to use it, and give you ballpark pricing during the visit so you can compare both options with real numbers. Learn more about our custom sunroom builds, call 770-333-8174, or schedule your free consultation.
Three-Season vs. Four-Season Sunroom FAQs
Can you use a 3 season sunroom in the winter?
Yes, on mild days, but not as a steady, warm room. A three-season sunroom has no insulation or heating, so it tracks the outdoor temperature.
Atlanta’s winters work in its favor, though: on a sunny 55-degree January afternoon, a three-season room can be one of the most pleasant spots in the house, and our mild winters make these rooms far more usable than they’d be up north. For steady comfort on frosty mornings, you’d need a four-season build.
Does a 4 season sunroom add value to your home?
Yes, and it typically adds more resale value than any other sunroom type. Because a four-season sunroom is permitted, insulated, and climate-controlled, it counts as heated living space and raises your home’s appraised square footage.
In the Atlanta market, that documented, code-compliant square footage supports a cleaner appraisal and resale, and it also usually counts toward your home for insurance purposes. A three-season room still adds appeal, but it’s usually valued as bonus or porch space rather than finished living area.
How much does it cost to convert a 3-season room to a 4-season room?
There’s no flat rate, because it depends on how the original room was built. A true conversion means adding insulation, upgrading to double-pane or Low-E glass, and tying in a heating and cooling source, usually a mini-split (about $3,500 and up) plus electrical work ($250 to $350 per drop), and it needs a permit because the room becomes heated square footage.
Converting often costs more than building it right the first time, so if year-round use is your goal, a four-season build from the start is usually the better value. We can price a specific conversion during a free in-home estimate in the Atlanta area.
Which type of sunroom is best?
There’s no single best type; the right one matches how you’ll use the space and your budget.
For Atlanta’s climate, a four-season sunroom is the better choice for daily, year-round use, since our hot, humid summers are hard on an uncooled glass room.
A three-season sunroom is the better choice for mild-month use on a leaner budget, and our mild winters make it usable more of the year than it would be up north. During the estimate, we right-size the recommendation to how you’ll actually use the room instead of pushing the biggest build.
Recent Comments