[porphyra]

Keeping door and windows open while it's very cold or very hot outside can lead to extremely high heating/air conditioning bills. Meanwhile, high quality energy recovery ventilators that can exchange air with the outside without ruining your insulation tend to be a lot more than $200.

[cehrlich]

cracking everything wide open for 5 minutes doesn't have too bad of an effect on temperature in my experience, and gives you good air for a few hours.

[xnx]

My home has very poor ventilation so I periodically will open the windows and blast a box fan to "flush" the dirty air out. If done quickly, there's not much thermal loss.

[dogma1138]

It really depends on the house, if you have low thermal mass home then airing it out would definitely lead to a substantial thermal loss.

[tonymet]

I meant the door to your office.