My current setup is a Liebert GXT4 double conversion UPS. I needed it to clean up the sloppy utility power. The transformer on the pole is about to blow and

My current setup is a Liebert GXT4 double conversion UPS. I needed it to clean up the sloppy utility power. The transformer on the pole is about to blow and the neighbors septic pump causes brown-outs and massive spikes 70-150V. The Liebert deals with it really well. It has noisy fans though so probably a deal breaker for you. It's also not cheap, but worth every penny. The cheaper UPS units blow up / smoke with my sloppy input power. I've roasted several tower APC variable power UPS units. When I finally get around to moving and have more land I plan to set up some inverters, charge controllers, LifePo4 battery banks, solar panels and maybe wind. That should be less noise than my current setup.