A glass vs polycarbonate greenhouse – what’s better?

The great glass vs polycarbonate greenhouse debate has been waging between gardeners, botanists, and horticulturists since Alfred Einhorn invented polycarbonate in the late 1890s.

However, greenhouses stretch back much further – even the ancient Romans used a makeshift version, most notably when Emperor Tiberius was advised to eat a cucumber a day for his health. This resulted in a stone chamber with a glass roof being built to grow the yummy vegetable en masse.

So, when it comes to a polycarbonate greenhouse vs a glass one, which material is best for your begonias and the planet? Keep reading for our side-by-side comparison and final judgement.

Polycarbonate greenhouse vs glass

Before picking a side, you need to understand the advantages and disadvantages of a polycarbonate greenhouse vs a glass one.

Polycarbonate greenhouse pros and cons

Advantages of polycarbonate greenhouses

Some of the good aspects of polycarbonate greenhouses include the following.

• Lightweight: Polycarbonate is lighter than glass, which makes it easier to transport and install.
• Cost-effective: Polycarbonate is typically less expensive than glass, which is beneficial for those on a budget.
• Impact resistance: Polycarbonate is stronger than glass, meaning it can withstand higher impacts. This makes it a good choice for areas with frequent hail, high winds, or those who throw stones.

Disadvantages of polycarbonate greenhouses

Some of the problems with polycarbonate greenhouses include the following.

• A shorter lifespan: Polycarbonate may discolour or deteriorate over time, meaning it needs to be replaced sooner than glass.
• Environmental impact: Polycarbonate is a type of plastic and therefore not biodegradable. It also releases toxic fumes when burned, making it unsuitable for landfill.

Glass greenhouse pros and cons

Advantages of glass greenhouses

Here are some areas where glass greenhouses trump their polycarbonate counterparts.

• Long lifespan: Glass is durable and long-lasting. It can survive extreme weather conditions and resist discolouration for years.
• Aesthetic: As a transparent material, glass allows natural sunlight to shine through it. This creates a visually appealing and functional greenhouse environment.
• Energy efficient: Glass can retain heat within the greenhouse during colder months and reduce the need for artificial heating, which will save you money on your heating bills.

Disadvantages of glass greenhouses

Glass greenhouses aren’t all roses and sunshine. Here are some of their downsides.

• Cost: Glass is more expensive than polycarbonate, especially if you choose thicker and stronger types so it can withstand a potential impact.
• Fragility: Glass is notoriously fragile and prone to breaking or cracking if it’s not handled carefully.

Polycarbonate greenhouse vs glass when it comes to the environment

When it comes to the environmental benefits of glass vs polycarbonate for your greenhouse, glass is the clear winner (pun intended). It’s a natural material, non-toxic, recyclable, and doesn’t release harmful gases when exposed to heat or sunlight. It’s also more durable and longer-lasting than polycarbonate, therefore reducing the need to replace it (and subsequently waste it).

On the other hand, polycarbonate is a synthetic material made from petroleum and other chemicals. While it can be recycled, it’s not biodegradable and can take hundreds of years to break down in a landfill. Furthermore, polycarbonate may release harmful gases when burned, which can contribute to air pollution.

What is the best glass for a greenhouse?

The best glass for your greenhouse will depend on your specific needs and climate conditions.

However, it’s worth considering the level of durability, insulation, and impact resistance you’d like, as well as your desired energy efficiency rating and how much you want it to cost you.

Let’s take a look at some of the most common types of glass used to make greenhouses.

Tempered glass

Strong and durable, tempered glass is made by heating it to a high temperature and then rapidly cooling it.

This makes it less likely to break than regular glass, meaning it’s a good choice for greenhouses in areas with high winds or hail.

Not only that, but tempered glass is a good insulator and will help retain the heat in your greenhouse.

Low-E glass

Low-emissivity (Low-E) glass has a special coating that reflects heat back into the greenhouse instead of letting it leak out.

This helps reduce heat loss during the winter and can also keep your greenhouse cool during the summer.

Low-E glass is also more energy-efficient than regular glass and will lower your heating and cooling bills.

Insulated glass

Insulated glass is made by sandwiching two or more layers of glass together, with a layer of gas or air in between (the filling).

This creates a barrier that helps keep the greenhouse insulated and reduces heat loss.

Insulated glass is a good choice for greenhouses in colder climates or where homeowners are concerned about rising energy costs.

Polycarbonate-coated glass

As discussed, polycarbonate is a durable plastic commonly used in greenhouses. You can coat it onto glass to provide extra durability and strength.

As polycarbonate-coated glass is more impact-resistant than regular glass, it’s a good choice for areas that suffer from high winds or hail. However, it’s not as environmentally friendly as the alternatives mentioned above.

Talk to a professional greenhouse builder or supplier to help determine the best type of glass for your needs.

Final thoughts

While polycarbonate has its benefits, glass is the more environmentally-friendly option for your greenhouse. Glass is a natural and sustainable material that can last for decades and is also recyclable.

By choosing glass, you not only create a beautiful and functional greenhouse but also contribute to a healthier and cleaner environment.

FAQs

Is glass or polycarbonate better for a greenhouse?

It depends on your priorities. If you’re looking for a cheap and virtually shatterproof material for your greenhouse, polycarbonate is the way to go. However, if you want an environmentally friendly, energy-efficient, and aesthetically pleasing material, glass is your best friend.

To eradicate the likelihood of the glass in your greenhouse shattering, opt for a thicker or reinforced type such as tempered glass.

Are polycarbonate greenhouses worth it?

If you’ve tried several varieties of glass greenhouses and none of them can withstand the extreme temperatures you’re plagued with, a polycarbonate greenhouse might be worth trying. They’re also cheaper than their glass counterparts, which makes growing your own food more affordable.

Related: Read our greenhouse installation cost guide for more information.