New storm windows have "weep" holes at the bottom. They are not very big, less than 1/4 inch (maybe 1/8 or even less), just 2 on each window on a narrow window and more for a larger window. On older homes, very often, the factory weeps get painted over and soon are ineffective. Too much air movement or bugs crawling through the holes, and the storm window doesn't serve much of it's purpose.
Storm windows were a great idea. They block most of the air from the wooden windows. They keep the wooden windows from being soaked with rain water. They contain an amount of air space, that may have an R value. BUT, They may intensify solar damage. The sun breaks down the paint and the glazing on the wooden windows right through the glass. If not properly maintaned, the sun will eventually affect the wood. Then there's the fact of condensation between the window and the storm window. Weeps are necessary. They just need to be really small to still be efficient.
I noticed that this is your first post, welcome to the forum. Please post again soon and check to see if anyone else has an idea about this question.
Tom in KY, Recommending new windows with insulated glass whenever your budget makes that an option.
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