I live in an area with no hills, I am jealous of you. Fortunately, we do have high winds here and I can use that to simulate hills, but it doesn't feel the same. Spin classes never made sense to me, I guess it is good for winter, but it doesn't really get cold where I live. It must be boring riding a bike in place. I think if I lived in a cold area, I'd just tough out the weather.