A question for my fellow hobbyists in cold climates

So I bought the elegoo mini heater for my Creality LD-00h, it heats up the chamber not only the VAT as I see most people recommend. I'm thinking of upgrading to a elegoo Saturn 4 ultra(12k or 16k) and I'm leaning towards the 12k since the mini heater is designed for the that printer(it has a dedicated attachment spot). Now my question is if the vat heater is better than a whole chamber heater or vice versa in cold climates? The wattage consumption isn't a problem for me, I'm just looking for what gives the best quality. My thoughts: Since the vat heater only heats the vat, wouldn't that be insufficient to keeping the chamber at a reliable temp when the outside ambient temp is low? Like how insulated can that plastic cover be? If it needs to blast heat into the vat to warm the chamber, wouldn't you run the risk of overheating the resin?

On the other hand: Is heating the chamber enough to keep the resin at a stable temp, like the var is on a metal box exposed to the cold ambient temp.

Would love any and all insight!