Some Simple Advice About Preventing Rust
I am going to give some advice about preventing rust. There are some air conditioning "experts" who won't understand or like this! If you live in a place where both heating and cooling are required during the seasons of the year, then buy auto-switchover thermostats. The ones I have bought are set to come on with cool air above 74F, and come on with heat below 71F. Unlike many thermostats, these control the temperature at plus or minus less than 1/2 degree. This prevents "dew" from accumulating on your gun steel during those wild swings in outside temperature.
DO NOT BUY an auto-switchover thermostat for "programming". Some think that it is most desirable to allow your home to heat up or cool down while you are at work. This is a gun's worst enemy, and it will also run up your power bill. It runs up your power bill because everything within the outer walls are heating up (or cooling down). So when the cool air is allowed to resume, it has to cool down all of that mass (brick, walls, flooring, ceilings, furniture, books, guns, etc).
Actually when I installed my auto-switchover thermostats my power usage dropped about 10%. That is what air conditioning companies DO NOT want to hear! They want to sell programmable thermostats.