I want to keep the temperature cool for running the LIC (Larg's Internet Cluster) but warm so I am comfortable.
I work in the tiny data center that is my shed. I want good light and a comfortable temperature.
I stuffed insulation between all the wooden beams in my shed. I lined the inside with plywood. I covered the windows with clear styrene sheet to make cheap double glazing. Insulating the door was a git. I wanted to cover the floor with another layer of something like vinyl, but have not managed to.
I lined the walls and ceiling with thick sheets of foam insulation. This came from the builder's merchant up the road. Try to walk in a wind carrying a massive flat surface. It's a hoot, I'm telling you. Each sheet is Quinn therm rigid polyurethane. It has shiny silver sides: this is laminated aluminum foil facing which acts as a vapor barrier. You could insulate the Antarctic with this stuff and put it on the Sun.
I bought ten huge sheets (2400mm x 1200mm x 50mm) of this polyurethane at £25 a sheet (£250). I cut the sheets into pieces and stuffed them into the gaps. To mark out the pieces I bought a permanent marker, a tape measure and a huge two meter long straight edge (£20). To cut the pieces I bought a workbench, a crosscut saw with fat teeth and a surform plane (£50). The builder's merchant is starting to like me.
I used the plywood to line the inside of the shed. I cut out rectangles, placed them over the insulation and nailed them to the shed's beams. The plywood also came from the builder's merchant. I bought ten huge sheets (2400mm x 1200mm x 6mm) at £8 a sheet (£80). I bought a box of screws, a drill, an HSS drill bit and a countersink drill bit (£10). I bought a hammer and a bag of nails (£15). I bought a crosscut saw with fine teeth to cut the plywood. The builder's merchant now smiles when I visit him.
My shed arrived with single-glazed windows. I used rigid clear plastic sheet to make secondary glazing. I think the material is cheapo drawn acrylic. I screwed the sheets to the wooden window frames. I bought a 6' by 4' sheet, 2mm thick (yes, imperial and metric) which the merchant very kindly plonked on his circular saw table and cut into six 2' squares (£30). I bought steel strips (3000mm x 10mm x 3mm), a box of small screws and a small drill bit (£20). The builder's merchant was disappointed.
Secondary glazing makes a big difference but it isn't the best. The gap between the panes is much bigger than 10mm so convection currents cause heat loss. The panes are not sealed so tiny air gaps cause more heat loss.