To go to your last line directly, NO!
That is an odd paragraph. The only way I can excuse it is by saying they were being very generalized all over the place.
Ironically resistive loads are not the hellcat for off grid. Its inductive loads, IE anything with motors. And within that sub group, SIZE matters. Your fridge has a motor but its inductive "Hit" is small enough that most inverters won't "hiccup" on it.
When a motor starts, in the first split instant, there is a huge current surge as compared to the current draw after it is up to speed. It is this current spike that can cause big voltage drops on the inverter and send its voltage mins into the toilet, potentially causing error trips faults, IE loss of backup power.
SO if there should be anything on his naughty list, it should be inductive loads, not resistive loads, which are basically uniform.
Now, giving him the benefit of the doubt, resistive heating tend to be large, so I would say his implied heating nono is based on just load size as opposed to the "structure" of the load.
Including incandescent lights is a bit of a stretch, unless you have a ton of them. Again its cumulative.
So technically speaking, resistive loads (Heating) can be dealt with IF YOU HAVE a big enough capacity from the inverters AND the battery bank.
Commonly speaking, they are the ones people generally look at last, because they are big and money is usually factor. SO, people usually shoot for going after the really important ones first, water pump (Yes I know, motor) fridges, microwave, lights, communications, etc... and maybe set the heating really, really low or use low wattage foot heaters (little box cubes)., as opposed to a central heating system.
Hope that helps....
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william fitch
Owner
www.WeAreSolar.com------------------------------