Does the use of Inverters SAVE electricity,if we use it during power cuts ? Manufacturers claim so.?

Answer 1

I agree with the previous answer. There are a couple of ways that a backup power supply could save you money. 1.) When you charge up the batteries during off-peak times (cheap energy) and then use that energy during on-peak times (expensive energy). 2.) If you use the stored energy to reduce your peak power demand (only if you are being charged for demand).
Even in these cases, the cost due to the losses in the inverter would have to be less than those savings.

Answer 2

well, i dunno what kind of inverters you guys use, but where i stay, they actually increase my power bills. here's how: while there is power supply, the inverter uses a certain (high) amount to charge up its batteries. these batteries can only hold dc power, so some ac-to-dc conversion is involved. Next, when the power goes out, the inverter works backwards, "inverting" its stored dc to ac power & supplying your house.
This all seems pretty nice, but there's a catch: the two conversion stages (ac>dc & dc>ac), by their very nature, WASTE some power, as their efficiency after all can never be 100% (law of thermodynamics, man!).
So, using the inverter, for the same power usage you end up consuming some more units of power from your power grid. That's how the inverter spends more power. But of course, you can have electricity when the grid goes out.. you have to pay a price for your convenience, though.

maybe the guy who told you it "saves" meant it like how you "save" a word file... not how you "save" the world...