Traditionalist gardeners will usually use all their verbal skill to persuade to go for the old-school solution: glass greenhouse panels. Their greenhouse is their pride and joy and they will defend the practice of their teachers by all means. Glass rules and will continue to adorn the greenhouses in their backyards. However, more and more gardeners are getting to know modern trends and developments, recent technological advances and upgrades and they act accordingly. They invest into solutions which pay in the long term, enabling better energy efficiency, sturdier greenhouse and less yellowness over time.
The answer are polycarbonate sheets. These sheets of thermoplastic polymers have several advantages when compared to traditional greenhouse materials, glass especially. Yes, glass has been and is affordable, practical and you can buy it everywhere, but modern technology allows us to advance in very big steps.
Polycarbonate materials have been researched and developed in the past few years and now the market is full of panels of very good quality. But what is it that makes polycarbonate better than glass?
Everyone likes a good hammer. When you hold a hammer in your hands, everything looks like a nail, the old saying goes. I dare you to pick up a decent hammer and smack a polycarbonate panel with all your god-given might. The best effect you might cause is a scratch. These things are very strong and incredibly resistant to impact and hence used in many high-end toilet models. Many gardeners used to curse poor hawks and other birds which occasionally lost their way flying and ran straight into a glass greenhouse, leaving shards of glass everywhere. You will not have this problem if you look to invest into replacement plastic greenhouse glass.
This also means a much safer environment if you have children running around your garden. We all know how kids like to throw stones and balls around.
Furthermore, polycarbonate shows much better qualities than glass when it comes to thermal insulation. For example, 3mm thick glass will have the „R“ value (index of thermal insulation) of 0.93, while a 4mm twin-wall polycarbonate panel outclasses glass with an R value of 1.42. Even if the 4 mm polycarbonate panel is a bit more expensive than glass (in average around 50%), you will save money in the long run. Polycarbonate will not only last longer, it will provide much better thermal insulation.
This means you will be able to use your polycarbonate greenhouse for much longer that the guaranteed 10 years, you will also pay much less money on electricity, and may be able to get away with just a portable air conditioner like these as opposed to a traditional unit which consumes more power. And your greenhouse will be much lighter and you will have more options and freedom during construction, because polycarbonate panels weigh much less than glass.
One more thing that technology has helped to overcome is the so-called yellowness index. Polycarbonate used to cloud up over time, but recent advances with special films removed this problem. Finally, polycarbonate panels allow the light penetrating into the greenhouse to scatter and becomee diffused. This way light can get into areas it would notbe able to with glass panels.