winter where it is about 70 degrees and 40 outside
Installing fans in a none AC'd building can be very effective, when strategically located.
Roof fans, gable fans and ceiling fans are effective.
Fan blade size is important.
Look for models that move a large volume of air, so as to cool the room down rapidly.
2 and 3 speed or variable speed models are the way to go.
Thermostatically controlled ceiling and roof exhaust fans available on the market.
On initial entry into a ''hot'' room, start the fans on ''HIGH''---
adjust to a slower speed after the heated air is removed.
A 36" fan will move lots of air.
20" fans will be adequate, when there is an adequate quantity of them.
Select the size of fans and the quantity of fans, that will suffice for the size of the facility.
A vaned fans are beneficial.
Fans with louvers will close, when the air flow is ''off''---keeping bugs, birds, or the like from entering.
Exhaust the hot air at or near the roof.
Pull fresh air ''IN'' near the bottom of the facility, preferably from the shaded side of the building,
or away from direct sunlight.
A furnace style filter can to affixed on an inlet-fan frame or housing, for the ''air intake'' side of the building.
The filter and screens will keep those unwanted insects, dust and debris from being sucked into the building.
Screens on open windows are needed.
I cool down a 2000 sq foot facility with a single 36" fan, set on HI, in a matter of a few minutes,
with a couple screened windows open.
3-4, 20" floor style fans, suspended or located above head height, will keep the air moving nicely,
and be out of the way (head clearance).
Elevating the fans will not blow around the sawdust, on or near the floor.
Affix a furnace filter, over the inlet side of each of the floor style fans.
The filter will catch/trap small particles of dust.
Make the filters easily removable, so you can blow out the dust with an air compressor, or the like.
(Duct tape can be used, as a temporary hold down device, to keep the filter in place. Place a short strip, along each edge---all four sides---holding the paper frame to the metal from on the fan).
The above, as described, has worked very well for me.
I have a heated shop but no A/C yet so I am out there at 3 seasons.
I build all year long and if there was more that 7 days in a week I would use them too. Since winter is the slower time for home construction I always book in a few projects as a "fill in projects" which would take care of the things like personal Christmas and birthday gifts as well as any other special "no hurry-round to it" builds that customeres say, "well, no hurry build it when you can." To be fair to answer your question there is really no difference between summer and winter as far as to when I build the most.
I down scaled from a larger shop that was not located at home , returning back home where I began. This is an oversized double car garage. I have remodeled most of it and it is heated and has all the lighting and the equiptment to do everything in cabinetary, furniture and art.