Do household ovens ventilate heat to the outdoors?
I've never seen one that vents to outside, and I've used kitchens in several countries. 

In many places we need to heat our houses for quite a few months each year, and the waste heat from cooking is very welcome. I try to avoid using my oven in summer, choosing other things to eat instead.

Note that modern ovens are designed to be well sealed and well insulated, but many have a fan to cool the space in which the oven is installed; that's the source of warm air into the room with the door shut.

You can minimise the heat produced (i.e. the electricity used by both the oven and the air conditioning) by opening the door as little as possible, and by only preheating if you really need to. A well-insulated oven can be turned off a few minutes early for many dishes as it will retain enough heat to carry on cooking. In other words - cook as efficiently as possible.  The benefit of this is greater if you're using air conditioning.