Now is the time to have your AC unit checked out. It's been off for a while and won't be needed for a few months. If you have been in your home for between ten and twelve years and your home was eight or nine years old when you bought it, your AC unit is upwards of twenty years old. Units that are that old are at the end of their lifespan and need to be replaced. Unfortunately, the system may pump out heat in those last years but could also be pumping out carbon monoxide directly into your home. Carbon monoxide can kill you. A specific part tends to fail which then allows a free path for this tasteless and scentless gas. This part is called the heat exchanger. It is specific to gas units. A flame is basically right up beside a metal divider with a blower on the other side. When natural gas burns just like any other fossil fuel it gives off carbon monoxide. If this metal divider called the heat exchanger degrades and begins to get holes in it, then the carbon monoxide is blown into your home. It's inevitable that units this old will have this happen so have a service tech take a look at your unit before winter comes and prices go up. At the very least, install a carbon monoxide detector in your home before winter comes (sooner if you have other gas appliances).