How to upgrade your 3 season sunroom to a 4 season space Image

How to upgrade your 3 season sunroom to a 4 season space

By Lucas on Aug 08, 2017

If you have a 3 season sunroom, you’re already better off than everyone without one. If you want to take it to the next level to get the most use out of your semi-outdoor space, you need to upgrade it to a 4 season sunroom.

First of all, what exactly is a 3 season sunroom? It’s an extension of your home comprised of mostly glass and screen, but it’s only used during the warmer months (not winter). has a great video highlighting some benefits of a 3 season sunroom and they also share some information about the importance of letting your home breathe.     

One of the biggest reasons you would want a room with many screens is so you can relax in the comfort of your home and save on energy. Beat the heat by turning the air conditioner off, opening your windows, and taking a seat in your sunroom with a good book. That said, the spring and fall are also good times to rely on quality screening to get some fresh air and increase the comfort of your home.   

Phantom Screens 30sec Cr1 from Montana Steele on Vimeo.

The difference between a 3 and 4 season sunroom

There are three factors that separate you from enjoying your sunroom all winter; glass, insulation, and HVAC.

In 3 season sunrooms, single pane tempered glass is typically used. This type of glass is not energy efficient, meaning it won’t keep any heat in. To make your space useable for winter, you need to upgrade the windows to glazed energy efficient panes. Not only will this glass keep the heat in during the winter, it will protect you from harmful UV rays.

For insulation, 3 season sunrooms usually have some in the floors, walls, and roof. In 4 season sunrooms, the quality of the insulation is better and there is also more of it. While ensuring your space in fully insulated, you should also make sure the room is airtight. If air isn’t escaping, that means you can efficiently heat the sunroom through the winter.


As for your HVAC, it’s possible that your 3 season sunroom already has it, but it’s more for warming up a chilly evening in the fall. Since you lack the right glass and high quality insulation, your HVAC won’t heat the entire room sufficiently. In a 4 season sunroom, you can fully rely on your HVAC to heat or cool your space no matter what time of year it is.

If you’re thinking of selling and buying a new home, it’s possible that upgrading your sunroom to a 4 season space could be a great way to win over the next potential buyers that walk through your home. The Greater Toronto Area (GTA) is known for its harsh winters, so a sunroom suitable for the cold would be an attractive feature.