nightvision
Petty Officer 1st Class
- Joined
- Mar 7, 2004
- Messages
- 252
Hi all,
I like to give an update on my "attic fan" post below. Well, I decided to install a 3.4 amp attic fan a couple weeks ago and have some preliminary data to share. Here is a little background. My house is about 1450 square feet, one story, vaulted ceiling, tile roof, and was built in 2000. The house have two gable vents and eight (3 inch by 22 inch) soffit vents. It took me about 30 minutes to install the attic fan to one of the gable vent and hard wire it into a closet light. The fan has an auto therometer setting. I also added an on and off switch, so I can turn it on and off with out going into the attic. My intent is not to use the attic fan while the AC is running. Some have said that the cool air may be suck out of the home and I do agree with that.
Today, it was rather warm, so I started my experiment. I placed a remote digital therometer in the attic, which I can monitor in my house. Here are some results.
Time Attic Temp Ambient Temp Room Temp
7:00 pm 97 80 76
9:00 pm 83 67 74
10:00 pm 78 67 73
My data showed that the fan dropped the attic temp from 97 degree to 83 degree, a 14 degree drop in about 2 hours. One hour later it dropped the attic temp another 5 degrees. These number seems promising. I will have to do some control test and do some more trials. At about 7:30 pm, pulled out a latter and put my hand on the outside of the gable and indeed very hot air were coming out.
This fan takes about 400 watts to run, my calculation shows that it will cost about $6.00 to run a month (5 hours a day, 30 days, at 10 cent per Kilowatt hour). My central AC uses about 4500 watts, my calculation shows that it will cost about $67.50 (5 hours a day, 30 days, at 10 cent per Kilowatt hour).
We'll see if the attic fan can save me money on cooling cost.
I'll post my findings later.
I like to give an update on my "attic fan" post below. Well, I decided to install a 3.4 amp attic fan a couple weeks ago and have some preliminary data to share. Here is a little background. My house is about 1450 square feet, one story, vaulted ceiling, tile roof, and was built in 2000. The house have two gable vents and eight (3 inch by 22 inch) soffit vents. It took me about 30 minutes to install the attic fan to one of the gable vent and hard wire it into a closet light. The fan has an auto therometer setting. I also added an on and off switch, so I can turn it on and off with out going into the attic. My intent is not to use the attic fan while the AC is running. Some have said that the cool air may be suck out of the home and I do agree with that.
Today, it was rather warm, so I started my experiment. I placed a remote digital therometer in the attic, which I can monitor in my house. Here are some results.
Time Attic Temp Ambient Temp Room Temp
7:00 pm 97 80 76
9:00 pm 83 67 74
10:00 pm 78 67 73
My data showed that the fan dropped the attic temp from 97 degree to 83 degree, a 14 degree drop in about 2 hours. One hour later it dropped the attic temp another 5 degrees. These number seems promising. I will have to do some control test and do some more trials. At about 7:30 pm, pulled out a latter and put my hand on the outside of the gable and indeed very hot air were coming out.
This fan takes about 400 watts to run, my calculation shows that it will cost about $6.00 to run a month (5 hours a day, 30 days, at 10 cent per Kilowatt hour). My central AC uses about 4500 watts, my calculation shows that it will cost about $67.50 (5 hours a day, 30 days, at 10 cent per Kilowatt hour).
We'll see if the attic fan can save me money on cooling cost.
I'll post my findings later.
