We love to wax romantic about old stone homes and for good reason – they’re gorgeous! But in doing so we may sometimes perpetuate a big myth — that, thanks to those thick stone walls, old stone homes stay as cool as cucumbers on the hottest summer days.

Sorry to burst the bubble, but the truth depends in some circumstances on a home’s location and a scientific principle called thermal mass (building material’s ability to store heat).

An old stone home with very thick walls works well in a region of the country where temps fluctuate significantly from day to night. Think sunny Southwest. Here’s how it works:

The sun rises in the morning and its rays reach the earth, heating the outer layer of a home’s stone walls, which, in the a.m., are cool to the touch thanks to chilly night air. Because of stone’s density, heat seeps through the wall VERY slowly, so that by the time the sun sets, heat is just starting to reach the home’s cool interior. Bravo! That bit of warmth inside feels great when the night air turns chilly. When morning arrives and the sun rises again, interior warmth has dissipated, exterior walls are cool again and the process starts all over.

Old stone homes may be bad news in areas of the country where, during the summer, nighttime temps don’t drop dramatically and a cooling effect never occurs. Your home takes on the temperature of the surrounding environment and holds it — yikes — like a big ol’ bake oven! The solution comes in the form of insulation, placed somewhere inside the stones walls, energy efficient windows and an effective HVAC system.

Own an old stone home? Struggle to keep interior temps comfortable in the summer? Tell us your story!