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6 Tips To Help You Choose Your Greenhouse Polycarbonate Panels

greenhouse made with polycarbonate panels

Polycarbonate panels have revolutionized greenhouses forever. Polycarbonate panels are one of the most popular types of greenhouse coverings on the market, and rightfully so. 

But, not all polycarbonate panels are made the same. It’s important that you choose your polycarbonate panels wisely. This can be overwhelming since there are many different options.

Don’t worry. In this post, I’m going to help you decide what type of polycarbonate panels you should use on your greenhouse. 

Let’s get started. 


1. Thickness

Thickness is another important factor that you must consider when deciding on the type of polycarbonate panels.

The thickness of your polycarbonate panels will determine two main things: 

  1. Durability 
  2. Insulating ability

It is important to note that thickness and structure as different. Thickness refers to how thick the walls are, while structure refers to the number of panels that the wall uses.


2. Durability

The thickness of your greenhouse panels will determine how durable your greenhouse is. Thicker walls will have a higher wind resistance and snow load. 

When buying or purchasing a greenhouse kit you will typically get the option between single panel and double panel polycarbonate panels. 

For the highest durability you want to opt for double-panel polycarbonate panels. I would recommend at least 4mm for the wall and roof. 

4mm double-wall polycarbonate panels are great for area that experience heavy rain or snow, or strong winds. 

I would recommend opting for a thicker roof panels such as 6mm or 8mm panels. This will give your roof additional protection in the event that snow builds up on the roof or something falls directly on the roof. 

The great thing is that many greenhouse kits offer this as a standard option. 

If you are purchasing your greenhouse panels separately than your frame you will have more more options available. 

When purchasing separately you can opt for three wall polycarbonate panels or even 10mm or 16mm polycarbonate panels for maximum durability. 


3. Insulating Ability 

The thickness of a panel will also determine how well your greenhouse is insulated. A greenhouses coverings insulating ability is measured by the R-value. 

Larger R-values offer better insulation than smaller R-values. Fortunately, polycarbonate panels come in different sizes and different R-values. 

Depending on your needs and the weather around in your region, you can determine the best polycarbonate panels for your greenhouse. 

There are two common polycarbonate panels use on greenhouses and on greenhouse kits. 

  1. Single Wall Polycarboante 
  2. Double Wall Polycarbonate 

Single wall polycarbonate panels provide significant less insulating ability than double wall polycarbonate. 

Single wall polycarbonate walls are great if you live in regions with moderate weather where the lowest and highest temperatures do not reach too low or high. In this weather, your greenhouse will not require additional heating or ventilation system to maintain an ideal temperature. 

Double wall polycarbonate panels are much more suited for all types of weather. They preform much better in extreme heat and extreme cold. The higher R-value means that your greenhouse will be less susceptible to drastic changes in the temperature outside. 

Double wall polycarbonate panels are recommended if you live in regions where the temperature fluctuates and you want to avoid the use of heating or cooling systems inside your greenhouse. 

will also determine the R-value. The R-value determines how well it insulates your greenhouse. Larger R-values offer better insulation than smaller R-values

Polycarbonate panels are made in different thicknesses. For example, twin wall panels can be made with different thicknesses ranging from 6mm to 16mm panels.

The standard single-wall polycarbonate panels come with a thickness between 0.7mm and 5mm. 

Twin-wall polycarbonate panels come in thicknesses from 6mm to 16mm.

Tri-wall polycarbonate panels are not as common as single and twin-wall. There are only very few greenhouse kits that will allow you to purchase a kit with tri-wall as the baseline.

In most cases, you will need to purchase tri-wall polycarbonate panels separately and upgrade your greenhouse panel yourself.


4. Single Wall vs Double Wall - Structure 

Another important factor when choosing the type of polycarbonate panel is the structure. Structure and thickness are often confused but they aren’t the same. 

Structure refers to the number of internal walls that the polycarbonate panel has. The two most common options that you includes in greenhouse kits includes single wall and double wall polycarbonate panels. 


Single Wall

Single wall polycarbonate panels have a single layer of polycarbonate. This is a common option in polycarbonate greenhouses and typically results in a more affordable greenhouse.

Single wall polycarbonate panels are more lightweight, inexpensive, and shatter-resistant. This is the thinnest polycarbonate that you can place on your greenhouse. As a result, they are not as durable as other materials. They provide a high light transmission as other transparent materials such as glass.

Typically single-wall polycarbonate panels will allow between 80% and 90%% light transmission. On the other hand, single pane glass typically allows around 90% to 95% light transmission. 

Single wall polycarbonate panels are ideal if you are on a budget or if you live in an area where the climate is temperate. This is also preferred if you 


Twin Wall

Twin-wall polycarbonate panels use two layers of polycarbonate sheets and combine them at the middle with a joining piece of polycarbonate.

Twin walls are measured from the start of the first panel to the end o the second panel. Twin-wall panels are often the standard panels used for durable, long-lasting greenhouse. 

Twin-wall panels are ideal because they provide better insulation but also less light transmission. Twin wall panels typically have an R-value of 1.4 to 1.9. They also provide a 70% to 75% of light transmission, which is a 10-15% reduction compared to single-wall polycarbonate panels. 

I recommend twin-wall polycarbonate panels over single wall. Twin wall polycarbonate panels provide better insulation and durability than single-wall greenhouses. 

While they are more expensive you will likely save cost on heating, cooling, and ventilation equipment as well as energy. 



The tri wall is typically the thickest polycarbonate panels that you can install on a greenhouse. 

The tri-wall panels provide the highest level of insulation and are typically ideal for maintaining a consistent temperature inside your greenhouse. 

Tri-wall panels have an R-value of 1.9 to 2.5 depending on the thickness. These panels will have very few fluctuations in temperature when temperatures rise or fall outside. 

As a result, they typically only allow around 65% to 70% light transmission. When using these panels, you will likely need to use ventilation, heating, and cooling systems to ensure that the temperature inside stays within your ideal range. 


5. Budget

As with any investment you should always consider your budget. Single wall polycarbonate panels and greenhouse kits are less expensive than double wall polycarbonate panels. 

For reference a 8 x 8 ft single wall polycarbonate greenhouse kit will cost approximately $1,000 - $1,500. On the other hand, an 8 x 8 ft double wall polycarbonate panel greenhouse kit cost approximately $2,400 to $3,000. 

It’s important to consider what effect will choosing a single wall over a double wall mean for your greenhouse. 

If you live in regions with cold winters, harsh summers, or grow plants that need a particular temperature to thrive this will mean  you will likely need to purchase additional equipment if you have a single-wall polycarbonate greenhouse. 

This additional equipment might not be necessary due to the better insulating ability of twin-wall polycarbonate panels. 

Heating, ventilation, and cooling systems can cost upwards of $1,000 and $1,500 not to mention the additional energy consumption and learning required to ensure that all your systems are working properly as the temperature changes. 

In most cases, the additional investment on twin-wall polycarbonate panels will save you money, time, and energy in the long run. In addition, you end up with a greenhouse that is more durable and weather resistant. 


6. Light Transmission

Another very important thing to consider when choosing your polycarbonate panels is the light transmission. The thickness and structure of polycarbonates will determine how much light enteres your greenhouse. 

While it’s believed that polycarbonate is transparent like glass, its not. Polycarbonate is nearly transparent and often referred to as opaque. 

The intensity of the opaquness of a polycarbonate panel will vary depending on the thickness and structure. The light transmission is typically measured in terms of a percent. 

As a rule of thumb, single-wall polycarbonate panels transmit more light than double-wall polycarbonate panels. Also, thicker panels transmit less light than thinner panels. 

For example a twin-wall 4mm polycarbonate panel will transmit more light than a 8mm twin-wall polycarbonate panel. Likewise, a 4mm single-wall panel will transmit more light than a 4mm twin-wall polycarbonate panel. 

This is an important to consider if your greenhouse will receive limited light or if you live in a region where direct sunlight is limited. If this is the case, you should opt for a thinner wall such as a 4mm double-wall over a 8mm double-wall. 

If you live in an area where the weather is harsh and you require a thick double-wall you can always opt for a lighting system to compensate for the limited light. 

As a rule of thumb I recommend a 4mm for temperate climtaes because it provide a high level of durability, insulating ability, and light transmission that is ideal for plant growth. 

Below is a table that breaks down the light transmission of different polycarbonate panels as well as different greenhouse coverings. 


Polycarbonte Greenhouse Recommendations 

There are many polycarbonate greenhouse ktis on the market. It can take hours of research to determine the the different models available and what type of polycarbonate panels they are using. 

In this section, my goal is to provide you with the best polycarbonate greenhouse kits for each size of polycarbonate panel. 


Single-Wall Polycarbonate Panel

Single wall polycarbonate panels are best for regions who have mild climate conditions with less extreme weather conditions. 


1. Hyrbid Greenhouse

Roof Panel: 4mm 

Wall Panel:  0.7mm

The hybrid greenhouse is a great option if you are looking for affordability but want to ensure that you have a durable roof. 

This greenhouse comes with a 4mm roof panel and 0.7mm wall panels. Since the wall panels play a less important role on a gable greenhouse the 4mm roof provide plenty of durability for regions that experience snow or rain. 


2. Snap and Grow Greenhouse

Roof Panel: 0.7mm 

Wall Panel:  0.7mm

If you are looking for a greenhouse and you are not worried about durability then the Snap and Grow series is the best fit. It's extremely affordable and it comes in a wide range of sizes. 

Best Twin-Wall Polycarbonate Greenhouse

1. Sigma Greenhouse and Sungrow Greenhouse

Roof Panel: 6mm 

Wall Panel:  6mm

The sigma greenhouse is a great option if you are looking for a twin-wall Polycarbonate greenhouse. I highly recommend this greenhouse becuase not only is it affordable but it comes with many features that other greenhouses don't include. 

First, it comes with a steel frame for additional durability compared to the aluminum frame standard with many other greenhouse models. 

Second, it comes with two built in vents and two doors (one on either side of the greenhouse for maximum veritility. 

Third, it comes in a variety of sizes as small as 6ft to as large as 32ft with the ability to easily extend your greenhouse at any time in the future. 


2. Mythos Greenhouse

Roof Panel: 4mm 

Wall Panel:  4mm

The Mythos greenhouse collection is a great option if you want to get a twin-wall greenhouse but you're on a lower budget. It also comes in various different sizes with a 6ft base width and comes as long as 14ft. 

This is a great range considering most of their models will not cost more rthan $2,000. If you are in need of a larger model you may want to opt for another greenhouse series. 


3. Grand Gardener Greenhouse

Roof Panel: 4mm 

Wall Panel:  6mm

The Grand Gardener is a great twin-wall greenhouse with many different options that allow you to build the ideal greenhouse for you. 

It comes in a variety of sizes with an 8 ft width as the base. You can purchase models as large as 20 ft long. 

In addition, its much taller than most greenhouses at the market with a 8ft roof compared to the standard 7ft roof of many other greenhouses. 


4. Glory Greenhouse 

Roof Panel: 10mm 

Wall Panel:  10mm

The Glory greenhouse has some of the thickes double wall you can find on a greenhouse polycarbonate kit. If you are looking for ultimate durability and reduced light transmission then this is the best option. 

Another benefit is that it comes with a 8 ft width as the base and varies in length from 8ft to as large as 20 ft. This is a great greenhouse for people who live in regions that experience harsh weather such as rain, heat, or snow. 


Benefits of Polycarbonate Panels 


One of the biggest game-changers of polycarbonate panels is that they are cost-effective. Glass greenhouses of similar size can be two to three times more expensive than polycarbonate greenhouses. 

While most people might believe that since polycarbonate panels are significantly cheaper they are also less effective. Fortunately, although they are less expensive they come with many of the same benefits and features of glass greenhouse panels. 

First, just like glass greenhouse panels, polycarbonate greenhouse panels are just as durable as glass, provide UV protection, are transparent, and provide diffused light that promotes plant growth. 


Lightweight and Durable

Polycarbonate is a lightweight and durable greenhouse covering. This is an uncommon features that many other greenhouse covering can’t offer. 

Glass is durable but it’s by no means lightweight. You can typically expect a glass greenhouse to weigh between two and three times more than the same polycarbonate greenhouse. 

Another important feature is that opolycarboante panels although they are lightweight they are durable. When compared to glass they are 250 times more resistant to impact. 

Polycarbonate panels are design to be shatter resistant. They will also not yellow or change color over time or due to over exposure. 


UV Protection

A commonly overlooked feature of polycarbonate panels is that they provide UV protection. This means that while you are gardening or working inside your greenhouse you are protected from dangerous UV rays. 

Its important to note that UV protection does not hinder plant growth. UV rays are not necessary for plant growth. Plants will not be impacted by UV protection and will still receive the required sunlight to prosper. 



Understanding polycarbonate panels is never an easy task. With so many different features that determine the effectiveness of polycarbonate panels, it can be overwhelming to understand if you are choosing the correct panels for your greenhouse.

Don’t worry, in this article, we’ve broken down the six key things you need to know when buying your polycarbonate panels as well as how each of these features affects the overall performance of the panels.