Customers in the southern US typically don't use covers because their cooling system is operating for most of the year. Customers in the northeast regions have a shorter cooling season and in these regions covers are often bundled with their equipment or sold as a popular aftermarket accessory. In the midwest, covers are a newer concept, but have a very high growth rate as compared to other HVAC products. In many regions consumers will not pay for a cooling system until a cover has been supplied.