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How to Insulate your Greenhouse with TekFoil™ Reflective Insulation

Temperatures are finally dropping and winter is settling in. Hopefully, you have installed heaters in your greenhouse so you can keep growing regardless of the weather, but did you remember to insulate? Insulating your greenhouse with TekFoil can greatly reduce the amount you spend on heating your greenhouse because less heat will be able to escape. Growers Supply carries many varieties of TekFoil Insulation, so it is important to know which one is right for your application.


Radiant heat travels from warm surfaces to cool surfaces — take the sun heating the earth, for example. TekFoil Reflective Insulation has 0.97 reflectivity. This means it prevents radiant heat transfer by up to 97%, and allows only 3% of heat to get into or out of your greenhouse. Compare this to other types of insulation, such as fiberglass and foam, which allow 80 to 90% of radiant heat to pass through.


TekFoil is used for two reasons in greenhouse applications. First, it keeps most of the heat produced by your heaters inside the greenhouse where it belongs. This can be a huge help in reducing energy costs. Second, if the crops you are growing need artificial lighting, lining your greenhouse with TekFoil prevents that light from leaving the greenhouse, and reflects it back down at the plants, essentially recycling it.

Bubble Insulation


On the roof: During the winter, insulating the portion of your roof that faces north will reduce heat loss, in turn reducing fuel consumption. If you live in an extremely cold area, the southern-facing portion of the roof can be insulated as well for extra protection. When insulating the roof of your greenhouse, be careful to leave any vents operational.

On the end walls: Covering the north wall, or “cold wall,” of your greenhouse with TekFoil will prevent a lot of the heat and light loss you may have experienced before insulating.

Below bench wall surfaces: If you have benches lining your greenhouse walls, you may know that a major source of heat loss is on the exterior walls below bench height. Insulate this portion of the wall with TekFoil to keep the heat inside.

On the floor: More energy loss occurs through the floor of your greenhouse than through any other insulated surface during heater season. Reduce your heat loss up to 50% by applying cost-effective TekFoil on your floor.

Also, insulating any and all indoor growing areas when using artificial lighting can enhance light levels inside the greenhouse and help keep the light more evenly dispersed.


The major benefit of using TekFoil as greenhouse insulation is the lack of heat loss you will experience. The high reflectivity of TekFoil prevents almost all of the radiant heat transfer you might expect in a greenhouse that is heated, but not insulated. By keeping this heat in, your heaters won’t have to work so hard and you will see your energy bills drop. By the same token, if you choose to use TekFoil insulation in the summer months as well, there is less of a risk of your greenhouse overheating, and your fans will get more frequent breaks, also reducing energy costs. TekFoil helps regulate inside greenhouse temperatures all year long.Low tunnels insulated with TekFoil

If you are using artificial lighting to help your plants thrive, TekFoil can be a great way to keep that light inside the greenhouse. Rather than losing some of the light through the walls, TekFoil will reflect it back down and “reuse” it.

TekFoil also does not support the growth of bacteria or fungi in greenhouses, creating a healthier environment for you and your plants.


TekFoil Reflective Insulation from Growers Supply is made up of three materials. The first material is shiny, coated, metalized polyester. We call this material “Reflective.” The second material, known as “Bubble” is made up of polyester bubbles, kind of like the bubble wrap in packages, but stronger. The last material is called “White Poly” and is made up of exactly that, a layer of white polyethylene. We have mixed and matched these materials to come up with the best combinations to insulate your greenhouse.

Reflective/Bubble/Reflective: When insulating a greenhouse that is using artificial lights for plants, this TekFoil is great for keeping the heat and light inside. It can be used on the roof, walls and under benches. For a higher R-value, use Reflective/Bubble Bubble/Reflective for the same applications.

Reflective/Bubble/White Poly: If you plan to install radiant heating in the floor of your greenhouse, this TekFoil is the ideal insulation for under concrete. It is important to talk with one of our National Account Managers when installing TekFoil under concrete for best results. For an increase in R-value, use Reflective/Bubble Bubble/White Poly for the same application.

Clear Bubble Insulation: If you are looking to prevent overheating in your greenhouse, Clear Bubble Insulation is your answer. It transmits evenly diffused light through the greenhouse just as effectively as insulated glass.

TekFoil comes in a variety of other types, each with different purposes. If you are looking to use TekFoil for another application, contact a knowledgeable National Account Manager today or visit our TekFoil Buyer’s Guide.


TekFoil also works great in a variety of applications other than greenhouse insulation. Reflective insulation is an ideal insulator in commercial and agricultural buildings, as well as parts of your home such as attics, garages and basements.

If you have TekFoil scraps hanging around after you install it, don’t throw them out! These pieces are perfect for lining your coolers, insulating sheds and doghouses, putting under your sleeping bag and even as seat warmers!

3 Comments Post a comment
  1. Michael #

    I’ve planted ‘supersweet 100’s’ in a topsy turvy hanging planter. I’ve been rotating him, his name is Lucky, from indoors to outdoor depending on the outside temperature. What I can’t figure out is why when the sun comes out and hits him he goes from healthy looking to all the leaves and stems just droop. At first I thought I was watering too much, or too little, but my adjustments don’t seem to correct this issue. It’s been warm recently, 55+, and last night Lucky stayed out on the patio. At 6:30AM I got up and checked on him and he looked fantastic, I thought he was fixed. An couple hours later with plenty of sunshine and nearly 60 degrees with little to no wind and he is rapidly going droopy again. I can’t figure out what’s going on…any help?

    April 20, 2014
    • Hi Michael,

      With the details you’ve provided, I will do my best to help you out.Tomatoes do best in warm weather 75-85F. When transitioning from inside to outside, it needs to be done slowly so the plant can adjust. A few hours outside at a time slowly increased over several days.

      If your plant gets droopy during the day, it could mean that it isn’t getting enough water. Tomatoes need a lot of water, especially when they start producing fruit. A droopy plant could indicate that there is not enough water in the soil to draw up to the top of the plant. Water pressure inside the plant helps the plant support itself.

      Check the soil by sticking your finger in about an inch, if it’s dry, water the plant. Also make sure the soil is draining well. I recommend buying an inexpensive soil moisture meter to help determine when watering is appropriate.

      If this doesn’t solve the issue, you could also try some shading to reduce the rate of transpiration.

      I hope this helps! Happy gardening!
      Your Friends at Growers Supply

      April 24, 2014

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