The siding will crack, if not immediately then over time. If you put the bracket’s weight against a raised profile ridge, the raised profile ridge will be flattened against the building. If you have vinyl siding, each course has one or more raised profile ridges. But as often as not, they crack vinyl siding. A support bracket transfers the load of the air conditioner to the exterior of your building. They are structurally better than the wood block method described below.

Window air conditioner support brackets are sold online. The Problem with Vinyl Siding and Support Brackets It is too difficult to safely place such a mount on vinyl siding without cracking the siding. It may be that only floor models are allowed.Īir conditioner window mounts like this one sold at Home Depot are typically shown against very hard exteriors, like wood shingle. This problem is not encountered on wood or metal frame windows, which either have strong metal lips, or a lip-free step-down between interior stool and exterior sill.īefore installing an air conditioner in a vinyl window, check that your rental agreement permits window air conditioners. Your window will then be open to insects in the summer and substantial heat loss next winter. A window air conditioner placed on this lip can bend and crack the lip, or pop the corner welds of the window frame. The lip is not designed to carry the weight of a window air conditioner. The second baffle position is higher up on that lip another fuzzy strip presses against the bottom front of the lower sash. The first baffle position is at the bottom of the lower sash a fuzzy strip presses against either the lip or the windowsill. The lip supports one or more fuzzy baffles to stop air leaks. This lip interrupts what would otherwise be a smooth transition between interior stool and exterior sill. But unlike wood and metal, vinyl windows often achieve energy-efficiency with a lip that sticks up from the windowsill. Like wood and metal, vinyl windows can be sturdy and energy efficient. Some vinyl windows will have only one.ĭanger: Improper procedure when installing a window air conditioner can result in immediate or subsequent injury or death. This Pella 250 vinyl window has two air sealing lips, highlighted by sun and shadow.

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