[PILOON]

I use computer fans, often called 'muffin fans', come in 12 VDC or 110 AC and commonly sell about $10 range.
Generally measure 4" X4" X 1" and draw less than 1 amp.
The design is such that they move one heck of s lot of air for their compact size and the low amperage draw was a deffinate must for my tractor as the alternator is not all that big.
2 mounted inside my cab pushes enough air that even the biteing insects can't come in to attack me, LOL. ( around here we have deer fly, horse fly and all the rest of the critters that carry away chunks of meat)

Generally available in electronic surplus or wholsale supply houses.