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When considering enclosures able to reach higher chamber temperatures, insulation is essential to keep the heater power low.

Typical insulation materials are not transparent: cork (fire retardant, good for the inner hot side), rock wool, styrofoam panels, aluminium insulating panels (aluminium walls with foam in between).

Still, most of the time it's preferable to have one side of the enclosure transparent, to see what is happening inside without having to use a webcam (which may not work well or which may have a reduced lifespan when operated at 60-80 °C, due to capacitors and thermal noise in the sensor).

Rock wool, styrofoam panels and cork all offer about 0.032-0.038 W/(m K) thermal conductivity. In other words, a panel which is 50 * 50 * 1 cm will require about 0.85 W per each °C of temperature increase, or 8.5 W per 10 °C. A cubic 50 * 50 * 50 cm enclosure 2 cm thick would require 26 W to increase the inner temperature by 10 °C.

Replacing just one side with a transparent acrylic panel 3 mm thick would push the power requirement to about 190 W for every 10 °C of temperature increase, therefore finding a transparent insulation would be quite interesting.

What are the options to have a transparent, but still reasonably insulating, panel?

FarO
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Unfortunately there are very little solutions for fully transparent and thermally insulating materials. You may be able to use panels commonly used for greenhouses and hydroponics if you can accept losing full transparency and only being translucent. Another option may be to have two layers of your transparent material, with an air-gap in between, as dry and still air is a very good thermal insulator.

craftxbox
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Glass. Or more specifically, insulating two or three layer window panes between which is a vacuum or low heat conductive gas.

These panels are quite effective, compared to single panes: on a two layer sandwich, 9.5 mW/(m K) can be achieved with a Krypton filling, 5.5 mW/(m K) with Xenon. The sweet spot for avoiding too many loss from convection is usually below 10-15 mm per gas layer, depending on the gas. Three or even four glas panels can get away with much thicker total panes and avoid convection by having the gas insulator broken up into multiple layers as thin as 5 mm.

Such Mehrscheiben Isolierscheiben (insulating glazing) is often obtainable in any size from window makers and can come with a frame that contains the needed mechanisms to open or lock the box.

Trish
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How about using thermally insulating transparent silicone rubber sheets?

Perry Webb
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Never saw double pane windows of houses? Triple panes are not impossible.

Uwe
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