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[–]magnora7[S] 1 insightful - 1 fun1 insightful - 0 fun2 insightful - 1 fun -  (4 children)

Yeah I might get an attic fan, I was looking in to that today too. My temp gun read out 165F on the attic ceiling, and 145F on the floor. Pretty dang hot.

I tried a little experiment and put a gallon of water on the external unit. It cooled it from 140F to 95F, and it evaporated in about 90 seconds because of the heat. Then about 20 minutes later it was back up to 140F.

From a cost perspective, a gallon of water costs 1 cent. 1 cent of electricity is 100Wh. I think it'd be very hard to save 100Wh with one gallon going from 80F to 140F, not sure how many Joules (or watt-hours) that is.

[–]Tom_Bombadil 1 insightful - 1 fun1 insightful - 0 fun2 insightful - 1 fun -  (2 children)

Try the same experiment with a mister than can be directed at the cooling fins.

Dumping a gallon of water is a waste.

[–]magnora7[S] 1 insightful - 1 fun1 insightful - 0 fun2 insightful - 1 fun -  (1 child)

I sprinkled the gallon around the entire thing, I didn't just dump it

[–]Tom_Bombadil 2 insightful - 1 fun2 insightful - 0 fun3 insightful - 1 fun -  (0 children)

I'm not sure that I've ever heard anyone say they've sprinkled a gallon.

I'm sure you did, cause it was hot AF, and you were on a mission to fix it! ;-)

[–]Tom_Bombadil 1 insightful - 1 fun1 insightful - 0 fun2 insightful - 1 fun -  (0 children)

Definitely go with the attic fan.

The attic fan should blow the air in the attic to the outside.
There should be a separate vent in the attic that allows air to be drawn from the outside in.
The fan will create negative pressure (it's actually not negative) inside the attic, which will draw in cooler air.

The same applies in your house with window fans. Open windows in separate rooms/areas. Blow the hotter air out of the house (from the hot room, which is typically upstairs or a sun lit room) and let the colder exterior air draw in from the other room.

Blowing cool air into the house is much less effective.

Allow the negative pressure to work for you.