How to insulate a greenhouse

How To Insulate A Greenhouse In 4 Easy Steps.

In Temperature by Ana M

Insulation is a foolproof way to prevent the heat loss in your greenhouse. A good insulation is a key to heating a greenhouse in winter.

The main sources of the lost heat in the greenhouse are drafts and the actual structure of the greenhouse. So, based on these factors I am going to show you how to insulate a greenhouse.

Step 1 – Find the Spots of Chills in a Greenhouse

Instead of wasting money on extremely expensive fancy heaters find the sources of the cold air in your greenhouse. It can be anything from the gaps and cracks in the panes to the broken doors and vents.

insulate my greenhouse

So, make sure to fix anything that is cracked, get new panes if the old ones are broken. Seal any gaps in the greenhouse’s frame with the adhesive foam strip which you can also use to seal along the sides of the panes.

Finally, make sure that all the doors and vents are fit securely.

Step 2 – Choose Bubble Wrap Intended for Greenhouses

Optimize for a horticultural grade or agricultural bubble wrap. You might ask what is a horticultural bubble wrap and why to use it?

Well, there is an ordinary bubble wrap which is used for the packaging etc. If you have lots of it at home you can obviously use that.

However, it will seriously affect the transmission of light. About 10% of the light going into your greenhouse will be lost simply by using an ordinary bubble wrap which is a lot.

So, I would strongly recommend to use a horticultural one. It is toughened and UV stabilized. These extends the life of the bubble plastic to up to three years.

Also, remember that the larger the bubbles the more light will pass through.

The optimal size of the bubbles is 20 mm as these let maximum light through and retain the heat!

Step 3 – Insulate a greenhouse with bubble wrap

There is nothing that can beat this super cheap and durable material. I have been using it for years and it does the job just perfectly. Here is a quick step-by-step guide on how to attach bubble wrap to greenhouse easily:

  • Take the measurement of the sides, roof and ends of the greenhouse’s frame;
  • Attach the bubble wrap to the aluminum frame with the glazing clips. If you have a wooden greenhouse you can attach the bubble wrap to the frame with the nails or drawing pins. Just check what you have at the house. It is also possible to use a staple gun;
insulate my greenhouse
  • Insulate the roof by starting from the ridge and then down the sides;
  • Cut the bubble wrap to make the openings in the vents and doors.

For the double insulation you can use spacers which create an extra layer of insulating air between the bubble wrap and glazing.

How much of the greenhouse should I insulate with bubble wrap?

This is the most common question people ask. I would say that generally you can insulate the half of the greenhouse. It depends on the plants you are growing, think do they require warm conditions.

It does make sense to move the heat requiring plants into one half of the greenhouse which you are going to insulate.

To do that you need to make some sort of the curtain of bubble wrap from one side to another. Do it further down from the door to keep the plants away from the cold air.

Step 4 – Use Thermal Insulation Foil

I have heard that some people are insulating the north side of the greenhouse with the thermal insulation foil.

It is relatively inexpensive and is basically the same bubble plastic between two layers of silver foil. This structure allows the heat and light to be reflected back inside the greenhouse.

Also, don’t forget that snow is a natural insulator, so keeping a ‘coat’ of snow on your roof is not always a bad thing.

Now, before you order a roll of bubble wrap measure up the area you want to insulate. Then, leave on average an extra ten per cent of the wrapping for overlaps.

When setting up the bubble plastic instead of the cutting the wastage tuck the excess material under. This has the same functionality as spacers and creates some sort of the double glazing.

There are more materials which you can use to insulate a greenhouse, but I have personally only used a bubble wrap.

Please let me know in the comments if you found this article helpful and share your knowledge. Any suggestions are welcome.

Happy growing!

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