I had this question when I bought my first house with a garage.

I won't speak to whether this is worth doing or not. I will only suggest implementing some sort of temp monitoring system in the freezers and trying it out while you still have power.

Additionally, if you need the blanket then the situation for your freezer would be different I assume and it's thaw rate might be slower.

  The above advice is really all that is needed at this point

If it works no advice needed.

If it doesn't maybe consider the location of the freezers or consider a battery bank to achieve the same desired effect without killing power.

From what I understand lithium potassium batteries are what you want, but am still researching that myself for other applications.

It seems like your desire is passive cooling. Look into root cellars above and below ground depending on your elevation.

You mentioned you use your chest freezers for veggies and upright for bulk meat. I know you are planning on consolidating to one in emergencies.

I prefer looking at it like this:

chest freezer = bulk

upright = organization

fridge/freezer = convenience

I have three types of meat in my chest freezer. All bulk and stacked vertically. I have a spot where I keep milk jugs from Sam's stacked vertically in place of meat. That way I can practice first in first out method.

I removed the basket in my chest freezer and keep 10 whole chickens there, stacked vertically.

I buy my stacks on the same day, at Sam's. Seems like a lot of money and it is in the moment, but you save so much money by investing in food.

Got off track.

For the upright I would recommend RoseRed Homestead. Someone else recommended the channel on here and I like her setup. She also shops at Costco I believe.

I'm not a huge fan of the paper on the front system they use. I would rather have more protection for my inventory system and a system that wouldn't require replacing regularly. Magnets work great for that if you make them yourself or find a place that sells fridge magnets that don't suck.

Store clean drinking water in clean and safe containers in your freezer whether your power is on or not. It helps regardless.

My water in my milk jugs, even though I bleached them, is going down the toilet more than likely. That may just be me there without wanting to take the risk.

To me, it seems people don't really look at batteries as an option unless people are talking about solar.

For me it is like this: What powers the freezer? The battery. What keeps the battery from running out? The generator, electrical, solar, wind, fire, water, another battery, a bicycle, 500,000 hamsters.

You could probably get it done with 100,000 hamsters, but we believe in workers rights here.

Like I said before, the top has the only real advice you need here.

You are already doing better than most by shopping the wholesale, owning freezers, having a generator, and asking questions.

On the generator, depending on your make and model or if you already do so have, I would suggest researching multi fuel conversion kits or propane.