1. You can try to use a UPS a calculator (remember to factor in your monitor(s)) but in all honesty they are not very helpful unless you know how many watts you are pulling from the wall (since they all ask that).  In order to find that, you need a KillAWatt meter. (Very fun to use all around the house) Don’t be surprised if your whole system is only using ~100-150 watts at idle even if your PSU is 550-750Watts. Check your machine while gaming or encoding to get the maximum true power usage. Most are surprised it’s actually so little watts compared to their PSU size.
  2. Once you know how much power, the calculators will help you see how many mAh you want (How “big” the battery is, so how long your computer will stay on during an outage).
  3. Make sure your UPS has “Pure Sine Wave”. (NOT Simulated)
  4. Look at the replacement battery cost. Find a UPS with common (therefore cheaper) replacement batteries.  Most manufacturers will list a fake proprietary replacement model number for the UPS. In reality there are common numbers (e.g. UB1280) that you are just going to have to google to figure out. Plan to replace them ever 3-5 years if you are lucky.
  5. If you want the UPS to turn off your computer in the event of a prolonged power outage

These are a few of the UPS’s that would work for MOST people to keep MOST computers on for a few minutes (99.999% of power outages are flickers or brown-outs)

 

See some crazy high prices?