Exhaust into house possible?

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StoopidLungs

Well-Known Member
I just researched for hours and couldn't find a straight answer. I will be exhausting a 1000w light either into my attic, or into my laundry room. I haven't been able to find much info on ventilating into another room in the house. How much will my AC bill raise if my 6 inch max can fan is constantly pulling air into the attic? I was thinking venting into the next room- the laundry room- would be better. I know that it will probably get extremely hot in there, but at least during lights-off time I wouldn't be sucking cool air out of the house. Should I vent into attic or next room over, and why?
 
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StoopidLungs

Well-Known Member
I am only concerned with electric bill. I think I will save a lot by not wasting all that air when the lights are off.
 
dbkick

dbkick

Well-Known Member
if the attic is well vented, if not you may be asking for high humidity in the attic which isn't good. I exhaust a 1000 watt to the mechanical room in the winter, in the summer I switch it to dumping outside. I've found this winter (even though not cold much) I've had to cycle my hood fan to get my room air temperatures up( the light ventilation is in a closed loop from the room, no room air enters the light. but I found that the exhaust doens't really get that warm if the fan is running while the light is on.
 
Diablos

Diablos

Member
Do you have a drier in your laundry. If so it will have a big exhaust hose on it, up around the 200 - 250 mm, Go buy a "Y" piece (or T piece), and just pump out the same place the drier does.... Working smarter, not harder.
 
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rooky1985

Active Member
Diablos said:
Do you have a drier in your laundry. If so it will have a big exhaust hose on it, up around the 200 - 250 mm, Go buy a "Y" piece (or T piece), and just pump out the same place the drier does.... Working smarter, not harder.
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You beat me to it, I have done this before works great, and there is a minimal increase in temp saving electric costs (ac). In the winter months I exhaust into my home and save on heating.
 
Rancho Cucamonga

Rancho Cucamonga

Active Member
rooky1985 said:
You beat me to it, I have done this before works great, and there is a minimal increase in temp saving electric costs (ac). In the winter months I exhaust into my home and save on heating.
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Do you use a dehumidifier in the winter months? I did this at my last place and in the winter when I exhausted into my home the RH would rise dramatically, anywhere from 60-70%. Absolute heaven for mold and a dead giveaway with iced over windows and clouds of warm humid air hitting the cold air when opening front or garage doors.
I had to run a 700 watt dehumidifier about 12-18 hours a day to keep RH at 50%, which is still considered too high in winter months. I had to clean mold off certain areas on the walls about every 7-14 days, any wall that was a "cold wall" had mold issues at the corners.
 
jrainman

jrainman

Active Member
It does not matter ,you are still venting that same temp air in your house , your attic will become warmer ,because being that you are inducing air pressure in your attic space it will slow down the the air moving through the outside sofits ,So your temps will rise in your attic space therefore slowing down the rate of heat lost between your ceiling and your attic . so cost would be really no dif. Oh and dont ever decrease a duct line....You have a 6'' opening on your fan for the reason of moving the cfm that the fan is rated for , dryer vent is 4'' , you might as well take a match to 1/2 the money you spent on your fan and just burn it.
 
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rooky1985

Active Member
Rancho Cucamonga said:
Do you use a dehumidifier in the winter months? I did this at my last place and in the winter when I exhausted into my home the RH would rise dramatically, anywhere from 60-70%. Absolute heaven for mold and a dead giveaway with iced over windows and clouds of warm humid air hitting the cold air when opening front or garage doors.
I had to run a 700 watt dehumidifier about 12-18 hours a day to keep RH at 50%, which is still considered too high in winter months. I had to clean mold off certain areas on the walls about every 7-14 days, any wall that was a "cold wall" had mold issues at the corners.
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I did not have to run a dehumidifier, humidity in my area during the winter is next to nothing so it kind of worked as any heat source inside of a home would. I actually lowered my thermostat to 68 and my lights kept it a bout 73 degrees in a 2k square foot home. Now I put them outside in the summer and do some pheno hunting indoors during the winter.
 
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StoopidLungs

Well-Known Member
jrainman said:
It does not matter ,you are still venting that same temp air in your house , your attic will become warmer ,because being that you are inducing air pressure in your attic space it will slow down the the air moving through the outside sofits ,So your temps will rise in your attic space therefore slowing down the rate of heat lost between your ceiling and your attic . so cost would be really no dif. Oh and dont ever decrease a duct line....You have a 6'' opening on your fan for the reason of moving the cfm that the fan is rated for , dryer vent is 4'' , you might as well take a match to 1/2 the money you spent on your fan and just burn it.
Click to expand...
Yeah sounded like a good idea but I would be concerned with reducing the duct size. Thinking I will just vent into laundry room.
 
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StoopidLungs

Well-Known Member
jrainman said:
It does not matter ,you are still venting that same temp air in your house , your attic will become warmer ,because being that you are inducing air pressure in your attic space it will slow down the the air moving through the outside sofits ,So your temps will rise in your attic space therefore slowing down the rate of heat lost between your ceiling and your attic . so cost would be really no dif. Oh and dont ever decrease a duct line....You have a 6'' opening on your fan for the reason of moving the cfm that the fan is rated for , dryer vent is 4'' , you might as well take a match to 1/2 the money you spent on your fan and just burn it.
Click to expand...
I dont understand how the AC bill would be about the same... During lights off, I'd be venting cool air out of the house into the attic wasting cool air. Or I could vent the cool air into the other room, not wasting any. Hmmm...
 
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