I do all my building in my garage. I have heat and air conditioning, but I typically do not heat it all winter long, especially at night. If you are like me, it might be time to get some things in order. First I package up my batteries into military ammo cans so I can seal them tightly. It is important that you do not let them freeze. It is also important you place the batteries indoors in a safe place. I prefer a place where I can see them from time to time and a place with a fire extinguisher ready just in case.
Follow manufacturer recommendations on how to store your LiPo’s. Most suggest you not hold them with a full charge. Cycle them down a bit and put a correct charge on them before storing.
I also pack up all my glues as they too may no fair well in the cold. Certainly nothing drives me crazy like waiting for cold epoxy to come out of the bottle. I use a box so I can organize all the glues and get rid of stuff that looks like it has done its time.
I hang all my planes on the ceiling of the garage so those too need some attention. Get that old fuel out of the planes or recycle the existing fuel with new fuel that you can exchange during the winter if needed. A full fuel tank is much better than a half empty one as moisture can collect in the tank if it is left low on fuel. Clean up the engine and use some after run oil and rotate the engine to get that oil throughout the engine. I also spray all engine parts with WD40 or PB Blaster and bag the motors with a plastic bag. This keeps the dust off and allows the penetrating oil to stay without evaporating. The bagging also keeps the dust off.
On board batteries should be removed. I know this is a pain as some are in places that are hard to get to. In those cases get them charged and take your chances, but if you can get them out of your planes do so.
Now during the winter, spin those props once a month to rotate the oil.
Finally, you might take a look around to see if you can locate any LCD screens from you test equipment. I like to bring those indoors too. You have fuel so it will react when the jug has been opened and it is half empty with regard to moisture so get it into a safe place that has some heat stability. I know we all do this differently, so please post your ideas.