Greenhouse - Winter Power Savers ?

With our commercial propagation glasshouse, we will be looking to condense things into a smaller area. I will probably do this with wooden battens to stretch straining wire which I will then attach thermal screen. We already have an automated thermal screen, then we are not heating the roof of the greenhouse, the thermal screen is made with aluminium fabric to reflect the heat back down.

We close them during the winter as soon as day time temperatures start to drop, so to trap the heat generated from the sun.

Depending on the size of your greenhouse, height, it could also be possible to do the same. With eye bolts fitted down each side of the guttering, you could then stretch some straining wire that you could slide the thermal screen by hand, probably best to staple it to some roof battens for ease of sliding opening and closing. You are then making your greenhouse into a box shape, so your not heating the roof space.

 

And paint them matt black. Absorbs the heat better and is a good radiator.

 

All our heaters ,eg Greenhouse and props are on digital control and the greenhouse min has always been set at 4c which seems to readily keep most things ticking over well, some even growing away.
However think we will be taking it down to 1c or 2 c this winter.
Just glad we have 10mm twinwall polycarbonate glazing these days, must save a lot of heat, though its installation was due to footballs breaking the glass!