It won't be that that much, you should be fine, most fridge are energy efficient. The biggest problem with whole house backup is people don't understand simple math and rely too much on sales people. I should caveat, daytime and nighttime with and without solar is also different.
I'm going to repeat this again for others:
Bottom line, if you have an AC requirement, and are being told by the installer it works fine with just 2 PW, you are rolling the dice, be prepared to purchase a 3rd PW.
Lastly you should do your own math and due diligence, the PW is rated at 30A each but realistically it only provides about 28.5-29.5A for inrush startup, assuming you have absolutely no other load (lights, fridge, etc..) which is unrealistic, keep these factors in mind when calculating startup amperage needed without AC before making assumptions how well the soft starter will work and aggregate amperage and what 2 PW will support.