Many of you may know this but in case some don't thought I would post it. I like to avoid the gas engine starting on my plug-in hybrid but turning on the defroster, especially below 32F, usually starts it. I discovered that if I open both front windows a couple of inches, that will 90% of the time clear the windshield without needing to turn on the defroster. It does get chilly but with a coat, hat and gloves on, not too bad.
If I understand your previous posts, you have an Outlander? We found a similar problem with the Prius Prime. Our resolution: (1) pre-condition, and (2) regular heat directed to windshield. Pre-conditioning activated by one of the key fob buttons 20-30 minuets before leaving, will run the heater while drawing power from your charger. The battery will still be fully charged but the cabin will be nice having used grid power. We also found that instead of hitting "front defrost," we just turn on the heater and direct the air flow towards the windshield and middle to cabin. It works well enough for us. However, the cracked windows works too. Bob Wilson
I do have an Outlander PHEV but that is better at not turning on the gas engine when the defroster is utilized than my other vehicle, a Gen 1 Prius Plug-in. The Prius is the one that I mostly use the open window scenario on. The Outlander is also better at not turning the gas engine on under acceleration. The Prius requires a very light foot to keep the gas engine off, the Outlander generally stays in electric unless you use greater than moderate pressure.