I already asked dad to change the bulb.
Because the hiragana ends with an う sound, you know this word is a verb. The kanji itself means replace so the verb vocab version is to replace. You know that you're doing the replacing because of the air (える). You're replacing the air as quickly as you can because if you don't you wouldn't be able to breathe in this small room.
The reading is the same as the one you learned with the kanji.