1. Waste heat from lights, equipment, and people is constantly offsetting the heating energy, and contributing to cooling energy. There's so much equipment in office/commercial buildings, it's common to need air conditioning all through winter.
2. It's not just air temperature difference, it's also about solar radiation gain. Even in cold climate zones the peak load for cooling is significantly higher then the peak load for heating.
> Waste heat from lights
Use LEDs and this is irrelevant for a home.
> people is constantly offsetting the heating energy
Insignificant in the scheme of things. Humans can’t even keep themselves warm when holding still in 50F.
> it's also about solar radiation gain.
Do you realize how little sun cities in the north get during the winter? Conversely, solar electricity can conveniently capture plenty of electricity quite near the time it’s required in the South.
Peak air con time is when there is solar radiation. Peak heating time is in the dead of night.
[1] For example in Toronto, Ontario, the electric grid is fueled from hydro (and we get passive cooling from lake water). And yet, Toronto's urbanization is so intense (and still growing) so the city still needs to reduce the energy consumption of it's buildings to manage it's peak power consumption. And I would argue this still has a huge impact on CO2 emissions given the reduction of transportation emissions associated with high density areas.
Okay, the power company is named Toronto Hydro, but it buys electricity from whatever is available on the grid, be it hydro, gas, nuclear (Darlington wasn't built to power Ottawa...), wind (hello Chatham farmland!) or solar.