Years ago I gardened in a greenhouse that was covered with a space age film called “Tedlar.” It never really took off, but it did have some impressive characteristics. Now there is a next generation of greenhouse film that may dethrone the ubiquitous polycarbonate. It is called ETFE film. One common brand name of this film is “F-Clean®.” Special thanks to Shawn Speidel (with Soil Fertility Service, LLC www.SoilFertilityService.com), who brought me up to date on this material.
ETFE (ethylene tetrafluoroethylene), fluorine based plastic. While it is new to us in the US, it has long been used in Japan, Europe and China in commercial houses. It is also what was used on the Eden Project in Great Britain and the .
Advantages of ETFE glazings or “F-CLEAN®”
- More light- ETFE films are 94 % light transparent. This beats out clear glass and most polycarbonate glazings. In shady areas of the world 1% more light may result in 1% more ‘gain’ in terms of yield.
- Dirt Resistance- The low surface tension of the film means that all it takes to clean the greenhouse is a shower of rain or snow. Snow slides off easier helps maintain optimum light.
- Fire resistance- Like polycarbonate, ETFE films are self extinguishing material. ETFE, the base material from which F-CLEAN is made, is rated UL 94-0 by the Underwriters Laboratories Inc.
- Improved crop quality- Unlike glass or polycarbonate glazings, F-CLEAN® allows the penetration of ultraviolet light, which has a positive effect on the quality of fruit and plants. Fruits ripen more quickly and develop a better color. Flowers gain more intense color. UV light also makes plants less susceptible to disease. If you want, you can add a UV-block option to the process of making ETFE glazings.
- Anti Drip Characteristics- ETFE does not allow condensation to form which could drip onto the plants, fruit and flowers. Drops of condensation also reflect the sunlight, reducing incoming light.
- Diffused light- F-CLEAN® is available in both clear and diffused versions. Diffused light tends to grow plants better by eliminating shadows.
- Heat retention- if you use the optional double layered F-CLEAN® It will save more energy over single layer options. However, like any glazing, when you double or triple the layers, the amount of light entering the greenhouse is also reduced.
- Durability-ETFE has an approx. life of 15 years but F-Clean® is guaranteed for 10 years like polycarbonate (also 10 years). However, there are many greenhouses that have been covered with ETFE films that are over 27 years old and still show no sign of deterioration. It just depends what the manufacture wants to guarantee. Some expect it to last as long as 50-60 years.
- Strong enough to bear 400 times its own weight
- 25 to 50 times lighter than the other alternatives materials
- It can be stretched to three times its length without loss of elasticity
- a working temperature range of -300 °F to 300 °F
- It Is recyclable
Downside to ETFE
- Not readily available for home greenhouse growers (yet).
- It is prone to punctures by sharp edges or a sharp impact (knife), but can be patched
- Must be tensioned in order to function properly which requires specific types of mounting hardware.
- Transmits more sound than glass.
- It is usually applied in several layers that must be inflated and require steady air pressure thus working with ETFE is difficult for small building projects.