While you have my sympathy, be very careful with the thermostat at 45 degrees. If there's a cold spot in your house with water pipes in it, they could freeze. This is especially true if you have any pipes running in an exterior wall. If you do set the thermostat that low, keep checking every day to make sure your water is still running everywhere. Leave your bathroom doors open when you're not in them. Leave the cabinet doors under the kitchen and bathroom sinks open. If a pipe does freeze, warm it up quickly, by turning the house thermostat back up to 65 if necessary. Be especially careful if your house has CPVC pipes, as these will completely shatter if they freeze solid. If you have to, leave a trickle of water running from the sink.