Sunroom costs – the average price to add a sunroom to your home in 2021

Is their price per square-footage worth it? And, do average sunroom costs work out cheaper than a home addition?

garden room extension
(Image credit: Westbury Garden Rooms)

Biophilic design—incorporating nature in your living space—made a come back during the Covid-19 pandemic. With the stress associated with stay-at-home orders, homeowners longed for the calming effects of nature. What better way to achieve that than with a sunroom addition?

Sunrooms come in several designs but by definition, a sunroom is a room with large windows. It’s the windows, and the usage, that separates sunrooms from other home additions. And, with the recent rise in the cost of lumber, you may wonder if building a sunroom is less costly than a traditional home addition. How much does it cost to build a sunroom? And is it worth it?

Types of sunrooms

One important point is that a sunroom is not a greenhouse. A sunroom is designed to deflect the heat of direct sunlight, making the entire home more comfortable. It’s not designed to trap the heat in order to grow plants in the winter. Although, plants do love a sunroom. That said, a typical sunroom falls into two distinct categories: three-season and four-season. 

A three-season sunroom is for use during the comfortable seasons of the year. It may have fans to circulate the air, a window air conditioner, or a small heater to take the chill off in the morning. But for the most part, it lacks the insulation and utilities to make it tolerable year-round.

A four-season sunroom is insulated and climate-controlled. The roof, walls, and doors contain sufficient insulation to make its use comfortable all year. And, a four-season sunroom will have a knee wall about two-feet high in which to run electric wires for outlets or baseboard heaters.

How much does it cost to build a sunroom?

Is a sunroom cheaper to build than a regular home addition? Not according to Ken Ward, president of Ward’s Remodeling, Inc. in Arlington, Virginia. “Windows drive up the cost,” he says. “They are much more expensive than typical wall area which includes siding, sheathing, insulation, lumber, and drywall.” 

Average costs published by the home services marketplace Angi confirms this assessment. According to Angi, it costs an average of $150 to $300 per square foot to build a sunroom and $80 to $200 per square foot for a home addition. Of course, a three-season sunroom would be on the lower end of that range and a four-season room on the upper end.

Sunrooms also come in pre-fabricated kits you can assemble yourself. Most homeowners use these to transform an existing patio or deck, which wouldn’t hold the weight of a traditionally built room, into a three-season area. Professional builders prefer to call them patio covers.

Besides choosing between site-built and prefabricated, other factors that impact the cost of a sunroom include: 

  • The size of the room
  • Whether you want to use the room year-round
  • Where the room will join the home
  • Your area of the country
  • Permitting requirements
  • The cost of labor and materials
  • Any hidden problems

Keeping these variables in mind, Home Guide suggests the following average costs for different types of sunrooms.

  • A 12-foot by 12-foot, three-season sunroom: $11,500 to $33,000
  • The same size four-season sunroom: $28,500 to $47,500
  • A solarium with a glass roof: $30,000 to $100,000
  • A climate-controlled conservatory with peaked class roof: $50,000 to $150,000
  • Costs included in adding a sunroom

Cost of sunroom permitting

According to Ward, the permitting costs for building a sunroom is the same as a home addition. The fees vary by location and the scope of the work. For instance, a four-season room will require additional permits for electrical and plumbing, if included.

Building permits must be secured before construction begins. Normally, the general contractor handles this task. The cost of a permit depends on the cost of the job. Generally, there’s a minimum for the first few thousand and then a rate per thousand above that. Some locations also charge fees for plan reviews. According to Angi, the average building permit costs $1,305, or anywhere between $424 to $2,239 for most jobs.

Site prep and landscaping

According to Ward, a traditionally built sunroom requires the same type of foundation as a room addition with either perimeter or pier footings that support the weight of the structure. You may find prices for a concrete slab sunroom foundation online for under $10,000, but Ward finds that unrealistic unless you’re purchasing a pre-fabricated, DIY kit that’s lightweight and of lower quality than a traditional build.

After the excavation to prep the site, you’ll want to replace the grass and add some other landscaping elements.

Contractor costs

In most areas of the country, home remodeling contractors charge by the project. This method actually helps you when planning your budget. Depending on your geographic location, Angi estimates their fee adding 10- to 20-percent to your project total. 

Potential hidden costs

A contractor’s goal is always to bring a project to completion at or below budget. But sometimes, there are things that come up after the job begins.

  • Different types of window treatments are expensive. If you have close neighbors, you may want the added privacy that blinds or shades provide.
  • Having to move outdoor elements to make room for the addition. Think about tree roots, outdoor spigots, or electrical panels.
  • Adding a sunroom may increase your property taxes.
  • The addition may also impact your insurance rates.

Ways to save on sunroom costs

As already mentioned, purchasing a pre-fabricated sunroom kit and installing it yourself could save you money on labor and the foundation. 

Choose less costly materials. “Low-e glass with argon gas between the panes protects your flooring and fabrics,” says Ward. But, those energy-efficient, UV-blocking windows cost more. If you’re building a three-season sunroom with minimal furnishings, economy windows will save on your budget. 

Build small. Most of the time trimming just a few feet from the overall square footage of any addition can save you thousands of dollars.

Pros and cons of adding a sunroom

Is adding a sunroom to your home worth the money and effort? Let’s take a look at a few pros and cons.

Pros:

  • Protects the entire home from the heat of direct sunlight
  • Provides added living area for entertaining, family gatherings, or getting close to nature
  • Opens the view up from the home to see the mountains, beach, or garden
  • Adds natural light to the adjoining rooms

Cons:

  • Not as energy-efficient as a typical room addition
  • Could increase utility expenses
  • Unless window treatments are installed, a sunroom lacks privacy
  • Windows need regular cleaning

Choosing a sunroom contractor

The success of your sunroom project largely depends on the skill of the contractor in charge of the job. To find the perfect team to build your sunroom, look for the following:

  • Sunrooms are their specialty
  • How long they’ve been in business
  • They’re licensed and insured
  • You feel comfortable talking with them and they listen to your ideas
  • They have references and can show you jobs they’ve completed

Ask friends and coworkers for referrals when finding a contractor to select someone who meets these criteria.

Whether you choose to add a three-season sunroom or one you can use year-round, the uses abound. Imagine, enjoying a rain shower on a Sunday afternoon without the discomfort of getting wet. Or watching a meteor shower without having to slap at the mosquitoes. Sunrooms make the perfect play space for children, office space for the remote worker, or a protected location for your hot tub. 

Carol J. Alexander
Carol J. Alexander

Carol J. Alexander writes website copy, blog posts, and feature articles on home remodeling and construction topics from her home in the Shenandoah Valley of Virginia. In addition to Real Homes, notable clients include, This Old House, Family Handyman, and Florida Roofing magazine.