Greenhouses grow crops, and will be used even more in the future.
1. Most greenhouses use large amounts of fossil fuels for heating and even though they provide food they produce a lot of atmospheric warming and CO2. They would use far less fuel than they do if a means of keeping heat in was more feasible.
2. The sun's power provides enough heat to heat homes and greenhouses if less heat loss occurred through glass. No one has yet found a means to do that inexpensively.
3. A solution is in monolithic types of silica aerogels either created in sheets or rolls or as a sandwich between thin glass sheets. The insulating effect of aerogels is vastly higher than glass although it is in effect the same material, just infinitely more porous and it barely impedes light. (Silica Aerogels are generally known for being an extremely lightweight transparent solid (down to <0.05 g/cm3) with excellent thermal insulating properties, high temperature stability, very low dielectric constant, and extremely high surface area).
The cost for sheets of silica aerogels are presently astronomical, and infeasible for commercial (or home) use except for aerospace industry applications. A pressing need exists for economical production methods.
Markets for this technology are found in numerous places in addition to greenhouses.