Greenhouse Selection

Congratulations!  You’ve decided to purchase a greenhouse!  You’re about to join a wonderfully enthusiastic group of greenhouse hobbyists who truly enjoy greenhouse gardening. As you begin to investigate greenhouses, you’ll want to consider both your present and future needs. Careful planning will save you time money down the road.

Some greenhouses are large investments, so we recommend you are comfortable engaging with a supplier who has the expertise to offer you guidance and answer all of your questions.  This will help you determine which greenhouse will best suit your growing needs.

We’re very pleased to share our expertise as you do your greenhouse research. You will find the following greenhouse information very helpful in order for you to evaluate your greenhouse needs.

Please don’t be afraid to ask us questions. Your greenhouse purchase is a big decision, and we want to ensure that you are completely comfortable with your purchase!  You are always welcome to call us at 1-800-665-2124 with any greenhouse questions you have.

Greenhouse Styles

Free-standing greenhouses are very common and these include a traditional straight eave peaked greenhouse or a curved-eave (or curved roof) greenhouse.   Their square or rectangular shape provides maximum growing space, allowing room for benches on either side of the greenhouse, as well as across the back, or even down the center depending on the size of the greenhouse.

Home-attached, or lean-to greenhouses, are designed to attach directly to your home, your garage or any existing external wall.  If you do not have enough height on the wall to accommodate the back ridge of the greenhouse, we can customize this dimension for you.  Many people find lean-to greenhouses easily accessible and extremely convenient especially when installing the necessary power and water connections for the greenhouse operation.

Greenhouse Construction

An opinion that is shared throughout the greenhouse industry is that maintenance free aluminum frame greenhouses are best suited for long term use.  They can also accommodate a variety of glazing materials including glass and polycarbonate.

Because aluminum frames are maintenance-free, they will generally last a lifetime.  Wood frames are not maintenance-free and do not have life span that is as long as an aluminum framed greenhouse.

Not all greenhouse frames are built the same.  You will want to be sure to select a greenhouse frame that has been engineered to provide adequate structural strength. A quality greenhouse designed with the highest structural frame strength will include the following features.

  • Withstand harsh weather conditions such as high winds and snow loads.
  • Provide the required support for hanging baskets, grow lights, cooling and ventilation equipment and sidewall shelving.
  • Include screened, hinged storm doors instead of sliding doors. Sliding doors are not as energy efficient as storm doors, and will result in greater heat loss (costing you more money for heating). A screened door also allows additional ventilation.
  • An extensive selection of greenhouse sizes and styles to choose from.  Often budget and/or space will dictate the size of a greenhouse.
    Flexibility to increase the height of your greenhouse by placing it on top of a raised foundation wall.  You will require a “dropped” door so that the door will be at ground level. (Read on for more information regarding elevated height and “dropped” doors.)
  • Consider the desired overall height of your greenhouse. You can build the greenhouse up higher using a “kneewall” to achieve that additional height. However, if you choose to build on a “kneewall”, you will need to “drop” the door down to avoid high steps in and out of the greenhouse.   Some companies may charge additionally for this service, but Greenhouse Style Corporation is not one of them! We offer a free door drop with your greenhouse. Just let us know the measurement of your raiseded foundation wall. (Does not apply to Legacy or Sun Garden Greenhouse)

 Greenhouse Coverings


Glass has always been a greenhouse favorite.  It is extremely attractive; allowing plants to be visible from outside and offers plenty of natural light.  Single and double tempered, unbreakable glass is available. Double glass greenhouses offer maximum heat efficiency.

Greenhouse Tip: If you purchase a single glass greenhouse, you can increase the insulation factor by lining the interior of the greenhouse with a layer of plastic.  This will help retain heat when using the greenhouse during colder months.


Polycarbonate panels are better at heat efficiency than glass, so it really comes down to personal preference on which glazing material you like best.  These panels have insulating features that can reduce your heating costs by 30% or more. The thicker the polycarbonate, the better it is at retaining heat. Light transmission is diffused through the polycarbonate, eliminating plant burn, and the light transmission can be about 10% less compared to glass.

As far as retaining heat, 16mm polycarbonate is best, followed by 16mm double tempered glass, then 6mm twinwall polycarbonate, and lastly 3mm single tempered glass.

16mm fivewall polycarbonate is the most energy efficient glazing material in today’s greenhouse market. The light transmission is a bit lower at 62%. The benefit is an improved R value of 3.03 which is a 21% improvement over 16mm thick triplewall polycarbonate. A greenhouse glazed with our 16mm fivewall polycarbonate will cost 21% less to heat than a triplewall polycarbonate greenhouse.  The 16mm fivewall polycarbonate is also about 50% more efficient than insulated 16mm double tempered glass, 10mm triplewall polycarbonate and 8mm fourwall polycarbonate. It is approximately 80% more efficient than 6mm or 8mm twinwall polycarbonate. Arguably, it is the most energy efficient glazing material available in today’s greenhouse market.


What’s the R Value?

The R value is the unit used to measure the effectiveness of the thermal insulation offered by the type of greenhouse glazing. Different thickness of glass and polycarbonate coverings will result in different R values. The higher the R value, the greater the heating and cooling efficiency.

Listed below are the R values for the various types of greenhouse glazing options available:

3mm Single Tempered GlassR Value is 0.95
Double Tempered GlassR Value is 2.00
4mm Twin Wall PolycarbonateR Value is 1.43
6mm Twin Wall PolycarbonateR Value is 1.54
10mm Twin Wall PolycarbonateR Value is 1.89
16mm Triple Wall PolycarbonateR Value is 2.50
5 Wall PolycarbonateR Value is 3.03