A UPS (uninterrupted power supply) takes A.C. (alternating current) from the wall and charges an internal sealed battery. It then converts the D.C. (direct current) back to AC. It has from two to four outlets on it for whatever you want to plug into it.
The theory behind it is that when the ac from the wall stops, the battery is fully charged and can continue to provide uninterrupted ac to your devices.
The capacity of your internal battery determines how many amp hours of power your ups can supply. It was designed to give you time to safely power down your computer or bridge the gap on short power outages.
If your house battery bank replaced the sealed battery, it should basically work the same. The thing I would make sure of is the current limitation. I don't know how things you could power at once.
You also might run into some problems with the charging of the house bank. The charging circuit will more than likely be limited.
But I am sure the smart guys will correct my errors and give you the real poop.
Make sure your printer will work with the UPS. Laser printers especially don't like them. They will destroy the power supply in laser printer. The owners manual for the printer should have a warning if it is a problem.