That's not practical in most parts of the country in the winter, when the virus was at its worst. What's the cost after including increased heating and A/C usage?
Your comment just made me wonder if that's part of why the viruses are always worst in winter. Sure, there are likely other factors, like vitamin D, but...
Seems unlikely. If you had made your comment in 1950 when the idea of air conditioning in summer was unheard of you would have a point. However these days any house or building has cooling in summer. People are outside a bit more in summer, but not enough to make a difference.