That article is misleading because it only considers outdoor air temperatures.
Every electric and mechanical device we use produces waste heat. Humans and pets produce waste heat. The sun shining on a roof and through the windows heats a house.
Take the example of DC with average summer highs of 87 and winter lows of 28.
If it’s 87 outside a house with no AC full of people and pets, running appliances computers and lighting with the sun coming through the windows will easily get up to 100.
You AC needs to effectively move the temperature from 100 to 74.
The same thing applies in the winter. If it’s 28 outside a well insulated house full of people and residual solar heat would likely never drop below 48 or so.
Also the article picked 74 degrees which is fine for the summer but insane for the winter. Especially at night when the low temperatures hit.
If you pick something more reasonable like 68, you now have 20 degrees of heating and 26 of cooling.
Then when you consider that adding 20 degrees to the outside temperature means that in the summer you will need to run the AC pretty much all day. While in the winter day time temps + 20 degrees puts the indoor temperature right around 70 with no heat.