This is from a typical North Western European housing perspective where most (older) buildings will not have forced air/AC/heat pumps etc. for various reasons, and most houses are only heated using gas powered central heating with water based radiators for transport. This means if you want fresh air in winter, you're opening a window and wasting energy in the air that was heated.
I understand the workings of forced air-to-air heat exchangers and how they can warm or cool fresh air coming in and how that could improve the energy loss situation. My question is, is it that much better than just forcing fresh air in to mingle with the stale air and having the over-pressure leak out, perhaps at the opposite end of a room or low to the ground where it is colder?
Of course I understand that you will lose some efficiency over a heat exchanger, as you will be leaking a mix of air containing also a lot of stale energy out that has not properly transferred energy. But is it that much worse considering the added complexity of a heat exchanger? Any other downsides/advantages I should be aware of?