Hot And Vented Roof

Basically the term cold roof refers to a traditional roof or vented roof while hot roof refers to a roof that is not ventilated and which has foam insulation attached directly to the roof sheathing.

Hot and vented roof.

Vented roofs serve a number of different purposes and their roles vary from climate to climate. Most studies show anywhere from 1 to 5 maximum increase in surface temperature during the sunniest part of the day while at night the surface temperature drops faster than a regularly vented roof. The theory behind a hot roof system is that rather than allowing heat to escape through your roof you contain it in your attic space which can save on utility costs in theory. This is less of a concern for slate and similar product roofs.

Ventilation benefits a roof when it s hot outside as well. In mixed climates ventilation serves either role depending on the season. Good roof ventilation can do this but shingle color sun exposure and insulation are exponentially more important to overall energy efficiency than ventilation. Cool air in hot air out attic ventilation works on the principle that heated air naturally rises primarily utilizing two types of vents.

In colder climates the main purpose of a vented roof is to keep the roof cold and reduce the formation of ice dams. A secondary goal is to vent moisture that infiltrates the attic from the conditioned home. In hot climates the roof temperature will be much higher on an un vented roof resulting in much shorter shingle life. Traditional roofs employing asphalt shingles vented attics and insulation on the floor of the attic can get extremelyhot with surface roofing temperatures reaching up to 190 f during the summer.

This can easily create attic temperatures as high as 125 f. When the temperature outside rises the temperature on your roof can be nearly double. A hot roof is one where there is no ventilation required as the insulation is directly attached to the roof sheathing. The hotter an attic is the more expensive it is to cool the upstairs of a home.

Intake vents located at the lowest part of the roof under. A hot roof over a poorly vented attic translates into a very hot attic. Unfortunately the term hot roof is a misnomer as the roof really is not that much hotter than a normal roof.