> I do not know the reasoning that was used to calculate these guidelines. It is quite possible they were focused on factors other than CO2, such as maintaining

> I do not know the reasoning that was used to calculate these guidelines. It is quite possible they were focused on factors other than CO2, such as maintaining comfortable moisture levels I feel like humidity (or lack thereof) is what most are struggling with when it comes to comfortable air. A non-trivial % of my energy use goes towards dehumidification. I have to run a central unit 24/7 if I want to keep RH below 55% during summer months. You can immediately tell how long the HVAC system has been running when you walk into a building in this area. Some mornings you walk in and it feels like a mild sauna, even if the outside temps are mild. The problem is that in most systems the dehumidification is linked directly to the cooling. If you decouple these concerns, you can much more easily achieve comfort. Variable speed heat pumps are another way to approach this issue.