A glass greenhouse is still the ultimate greenhouse in this age ofplastics, acrylics and polycarbonates.
These other materials all suffer some shortcomings which are eliminated with glass.
Glass is durable, scratch resistant, and will not cloud over time.
It offers excellent light transmission and its heat loss is much less than other materials.
Its primary drawbacks are that it is difficult to work with for the do it yourself greenhouse builder and initial expense as a construction material.
Glass greenhouses are more expensive, initially than plastic or plexi-glass houses.
But over time they are much more economical.
Glass does not need replacement every few years, like some of the plastics, and because it will not cloud or scratch like some of the rigid plastics available, though the newer ones are much better.
The heat loss through glass is less than that lost through other materials, so heating costs in a glass greenhouse will be less than other materials.
Double paned glass will lose less heat than single paned glass, and this should be considered as an option, if possible.
If it is not, a covering of plastic inside the glass during the winter will offera pretty effective heat barrier and not cut the light transmission too much.
A double paned glass structure would be the best choice for a four season greenhouse.
A glass greenhouse, though more expensive initially, would be more economical in the long term and is much more attractive.
Even in an age of plastics, a glass greenhouse is still the ultimate choice for growing plants.