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Can a greenhouse be double glazed?

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I found several factors to consider when considering whether greenhouses can be double-glazed. I decided to compile my findings into this post which explores the topic of doubled-glazed greenhouses.

A greenhouse can be double-glazed. Not only is it possible, but it can also be an effective way of keeping a greenhouse warm through the winter months, helping certain plants or shrubs thrive. Although double glazing is generally more costly, it is a long-term investment that can save money on heating in cold weather.

Table of Contents

We will cover the many benefits of double-glazing a greenhouse and how even the initial extra cost of doing so will be more than well covered by the return on the investments and benefits.

Factors to consider when using double-glazed glass for a greenhouse

Double glazing will provide both if you want the best possible growing environment and energy efficiency. On average, gardeners have half the heating costs associated with single-pane glass greenhouses. The only real downside to double glazing is the initial cost, which is significantly more than a single-pane greenhouse.

Picture of close up of greenhouses

Double glazing your greenhouses is a long-term investment

Although prices are, on average, much higher, it is important to consider the long-term investment aspect of double glazing.

If your greenhouse will be a permanent fixture and you are unlikely to be swapping locations, investing in double glazing will begin to pay off within a few years.

Heating a greenhouse in the winter months can be very costly, but the heat retention of double-paned glass significantly lowers these costs.

Double-glazing greenhouses save heating costs.

Picture of greenhouse with white wash pain

Another way that double-glazed windows stay warm is by installing a special low-energy reflective coating, which is fitted on the inner glass pane. This coating acts as a highly effective insulator and reflects heat.

When comparing this to single-pane or plastic greenhouses that cannot store heat effectively, it is easy to see why double glazing can save many heating costs for a gardener.

Benefits of double-glazed greenhouses

Below is a list that breaks down the benefits of double-glazed greenhouses:

  • It provides around three times as much resistance to heat loss
  • Less extreme temperature shifts
  • Saves money in the long term
  • Improved sturdiness & durability
  • More aesthetically pleasing

Another great thing about using double-glazed glass panes is the potential to get them on the cheap and build your own. Windows are constantly popping up on upcycling websites, so if you have some construction skills or know someone who does, this could be a great option. 

You can grow plants all year round with double-glazed greenhouses

Although building your greenhouse might seem daunting, it is well worth it. You could grow all year round, even in the winter, if you choose double glazing.

Double-glazing is worth investing time, money, and energy in, whether you buy second-hand glass or a new greenhouse.

How much light doubled glazed glass lets in

One of the main concerns for a gardener when it comes to greenhouses is light penetration. It is generally thought that the more sunlight gets in, the better. This is true in some cases, but it depends greatly on what you intend to grow in your greenhouse. Some plants and vegetables will thrive in hot, sunny conditions, whereas others are better suited to less exposure to the sun.

Comparison of double-glazed glass to single-glazed glass for greenhouses

If we compare single-glazed horticultural glass with plain double-glazed glass, the results concerning light transmission are not hugely different.

Single glazing allows 95% of sunlight to get through, while double glazing allows 80% of the light to be transmitted.

Certain vegetables fair better with less sunlight throughout the day and can cope with the shade. So the slight drop in light transmission would benefit these winter growers.

The lower percentage of light streaming in from double-glazed greenhouses is not a problem.

Picture of greenhouse with tomatoes

The 15% decrease may seem significant, but it still lets more than enough light in for the greenhouse to be a thriving, growing environment. It is, in fact, only slightly lower than many twin-wall polycarbonate sheeting greenhouses, so it is nothing to worry about.

As long as a double-glazed greenhouse is in a position where it will get ample sunlight, there is no reason that it cannot be a brilliant growing environment.

The positioning of a double-glazed greenhouse

Another point to consider concerning a double-glazed greenhouse is where to position it. This is greatly influenced by the space available in your garden or allotment, but there are a few general rules to try and adhere to get the full potential out of your greenhouse.

Situate the double-glazed greenhouse where against the harsh nature

Picture of hoop house hidden by flowers

Each garden essentially has its micro-climate, and all conditions are unique. When positioning your greenhouse, a general rule is to avoid harsh winds and frost pockets while getting plenty of sun exposure.

Places that receive the full sun are best for double-glazed greenhouses

Again, it is important to establish what you will be growing in your greenhouse. Do plants generally need a lot of sunlight? Sun exposure is significant, as is afternoon shade to some plants and shrubs.

Factors to be thought of when positioning a greenhouse would be the intensity of sunlight it will receive in said position as well as its access to water or electricity.

However, too much-stored heat within the greenhouse will also not be great for plants. It is best to look into ventilation systems, especially for bigger greenhouses.

To aid you with this, I have made this article on why greenhouses should have ventilation. It covers the benefits for plants of doing so, such as added natural air flowing within to aid with photosynthesis and many more important considerations for having a greenhouse.

Flat surfaces with the great draining ground are also best for double-glazed greenhouses.

A greenhouse should be built on a flat structure with good ground-draining capacities. This will avoid frost building up in the wintertime.

It is also best to situate a greenhouse on the south side of a house, as this area generally gets the most sunlight throughout the day. Positioning it lengthways from north to south provides the greenhouse with more light in most cases.

The best-suited flooring for a double-glazed greenhouse

Picture of tropical style plants in a greenhouse

It’s a common misconception that concrete or brick foundations are the best materials to use when it comes to the floor of a greenhouse.

These floorings, however, can be the cause of mold and harboring diseases.

Bricks can be used as flooring for double-glazed greenhouses, but with considerations.

Bricks can add humidity to the greenhouse, but they should be laid over the sand to provide stability and drainage. Using these materials is also much more costly and requires more work.

Pea gravel is a great flooring option for double-glazed greenhouses

A simpler option would be better suited for the floor of a double-glazed greenhouse. One of the best combinations is pea gravel and specifically designed flooring for greenhouses.

The gravel flooring provides good drainage capabilities, while the specifically designed flooring helps to prevent weeds.

This flooring can also be easily cleaned and sanitized if signs of disease show – unlike concrete.

Wood foundation with stone is another good flooring option for double-glazed greenhouses.

Large wooden greenhouse

You may make your greenhouse foundation from wood and then fill it with crushed gravel or stone. This can then be overlaid with weed cloth.

This type of floor will be well-draining, fairly inexpensive, and easy to clean.

Look into lava rocks as a flooring option for double-glazed greenhouses

Landscape and lava rock also provides an exciting greenhouse flooring option.

The lava rocks are great for soaking up excess water and adding to the general humidity levels, but they may be difficult to clean.

There is no right or wrong in greenhouse flooring, but certain materials will promote insulation, and others can lose heat. Again, it is important to make a decision considering the plants you intend to grow and the specific needs of your greenhouse.


Conclusion on can a greenhouse be double glazed?

Double-glazed glass panes are more effective for all-year-round growing. This is due to their ability to retain heat, which is much better than single-pane glass or plastics. The difference in price compared to the single pane ones pays for itself in the years to come.

Another tip if you are looking to maximize heat retention in your greenhouse is to install a reflective layer on the inside of the double-glazed panes. This coating reflects the light and heat in the greenhouse, keeping it warmer for longer.

Hopefully, this article will be a great help to you! If you liked this one, subscribe to the form below to be notified about future content and releases.

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