Too-hot rooms are common in cottage country, and no amount of roof insulation completely solves the problem. What you really need is ventilation, and an openable skylight installed near the roof peak can deliver that. Open skylights boost ventilation throughout the whole cottage, allowing hot air to escape and cool breezes to enter more easily through all openings. Leaving skylights open an inch or two all day allows cool air to be pulled upstairs as hot air rises out the top. I’ve installed these in several cottages over the years, and they’ve always been the silver bullet for cooling hot lofts. Within a few minutes of opening them in the evening, your loft will get much cooler than it would with only windows.
Worried about leaving skylights open as a sunny day turns to rain while you’re out on the lake? The best skylights these days rarely leak and are solar powered, so they close automatically when they detect rain. A small, on-board photovoltaic cell keeps a built-in battery charged for use day and night. Some models also offer screens and blinds that open and close by remote control for skylights that are installed too high for manual operation.
Solar skylights cost about $1,500 each. Installation starts at $2,000.
Other tips to cool down your space:
Keeping your cottage a manageable temperature without expensive AC depends on regulating things the old-fashioned way. Close windows, blinds, and drapes during the day to retain that precious cool air, then open all windows as the sun goes down.
Want to improve the hot and cold weather performance of your classic open-rafter cottage? Consider adding insulating panels on top of the existing roof the next time you replace your shingles. Even a couple of inches of extruded polystyrene foam with a layer of 1/2″ plywood on top will let you keep the good looks of open rafters and roof boards visible inside, while also boosting the R-value and lessening the summertime heat load from the top down.