In college my buddies and I would host big parties at our house. The amount of people in our small house was rather astonishing. People would be crammed into our place like sardines. Having enough booze and food was always really tough. One thing though, we always saved on HVAC. Most of our parties were for the holiday season. The holiday season is the cold season, so that means heating. We never ran our heater during a big party. This saved us on a ton of energy for the day. The sheer amount of body heat worked better than our heater could actually. The party goers were drinking and raising their temperature too. Then they were crammed tight and dancing all over the place. The heat in the house was bad enough that most people would open windows and the front door. I can’t even imagine how angry I would be if I had the heater on at that point. It just makes sense not to use it. Also, I am on a tight budget. Why should a bunch of party goers get free heating out of my roommates and I? If we were going to spring for quality heating for one day, it would be a day where just we all got to enjoy it. We did a similar thing with AC in the summer. We did not run the AC system. The people just had to duck in the shade and use ice inside. We had to hide where the air conditioner system was kept though. People always would complain and try to get the cooling system on.