Just do the math and that will answer your question. Typically when running many AC devices these days you go thru a power supply too. Most of these are cheap
and inefficient and many will draw power even if the device is disconnected from them. So you have loss thru the inverter (typically at least 5% even on a high end inverter...low end ones are worse) then additonal loss thru the power supply.
I ran the numbers on an inverter-power supply set up on my boat a few years ago and came up w a 30% loss for that installation! Way more efficient to go direct DC.
You can also get DC-DC power supplies for devices which take other than 12V. More efficient than inverting from DC-AC then back to DC thru a power supply. For example, many devices now take 5V as supplied over USB interfaces. I installed a 12V to multiport USB adaptor last season which we use a lot now to charge/run small electronics
And my cat, also built in 2000, has a bunch of AC outlets (main salon
, and one in each cabin). They do come in handy for occassional use like running a power tool or a guest charging
their cell phone
, but for normal installed loads on the boat it is way more efficient to go direct DC.
I also control the inverter from the nav station. This way I can monitor
power use...especially with guests aboard. I usually turn on when requested and then turn it off when they are done and/or before I go to bed