Tell you what - let's do this test, which is more reflective of real life conditions.
You and I will do an unequipped bivi somewhere. No tents, stoves or sleeping bags. Only normal day-trip winter climbing clothing and gear (pack, screws, ice tools etc).
You will get a foam pad. Hell, you can bring a Thermarest if you want. I will get a fire. You can't come anywhere near my fire and I can't come anywhere near your foam pad. We will see who is warmer through the night.