Use basement as return air plenum?
- Thread starter Garry
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First of all , you say the basement is insulated . Is it sealed to prevent the infiltration of dust , mold , mildew , excess moisture , and extraneous odors ?
Second , I have no idea if this is permissible per tour local code ?
Any reason you do not want to install ducting to the furnace return air ?
Do not forget air filtration .
God bless
Wyr
Second , I have no idea if this is permissible per tour local code ?
Any reason you do not want to install ducting to the furnace return air ?
Do not forget air filtration .
God bless
Wyr
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Thanks Wyr. I see your point that dust in the return air would be deposited in the basement rather in a duct. But the heated air would still be being drawn through the furnace filter.
The walls are sealed with dry-lock pro and insulated with 3/4" EPS and another 3/4" air space from the firing strips; then 1/2 dry wall. The door and windows are energy star rated. End joists and band boards have been calked and insulated. There is no moisture seepage. Neither mold, mildew nor air filtration should be a problem. Air filtration into the basement would be far less than from the house above, since the basement is mostly underground.
The 60 year old house has poorly designed and constructed return air ducts. One duct was never completed, and the leaks in the other ducts draw more air from the basement than from the house. Much of the air is currenly returning down the basement steps. I plan to add more return air registers to balance the flow.
Returning air to the insulated basement along with radiant heat from the hot air ducts would provide the desired amount of heat to the basement area. On the coldest days/nights, heat from a wood stove in the basement could rise through the return air openings when the furnace is off, or mix with and preheat the return air when the furnace is on.
The walls are sealed with dry-lock pro and insulated with 3/4" EPS and another 3/4" air space from the firing strips; then 1/2 dry wall. The door and windows are energy star rated. End joists and band boards have been calked and insulated. There is no moisture seepage. Neither mold, mildew nor air filtration should be a problem. Air filtration into the basement would be far less than from the house above, since the basement is mostly underground.
The 60 year old house has poorly designed and constructed return air ducts. One duct was never completed, and the leaks in the other ducts draw more air from the basement than from the house. Much of the air is currenly returning down the basement steps. I plan to add more return air registers to balance the flow.
Returning air to the insulated basement along with radiant heat from the hot air ducts would provide the desired amount of heat to the basement area. On the coldest days/nights, heat from a wood stove in the basement could rise through the return air openings when the furnace is off, or mix with and preheat the return air when the furnace is on.
Garry, I agree with your thinking. The only downside I see is if we would expect individual returns to be part of the dust collection system and that is not such a big problem that it couldn't be ignored or easily addressed by adding individual filters. Also, having the return in the basement will put it under negative pressure compared to the rest of the house, so any dust generated by woodstove operation will stay in the basement, and be filtered before returning to the upper floors.
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WARNING - DANGER: Using the basement as a return air plenum would create a low pressure around the furnace, potentially affecting combustion venting and mixing combustion products including deadly CO with the return air.
The instructions for my Goodman GMP125-4 furnace address this on page 9:
When the ducts are installed so that supply ducts carry air circulated by the furnace to areas outside the space containing the furnace, the return air shall be handled by a duct or ducts sealed to the furnace and terminated outside the space containing the furnace.
Sorry I didn't read the instructions before initially posting the question.
The instructions for my Goodman GMP125-4 furnace address this on page 9:
When the ducts are installed so that supply ducts carry air circulated by the furnace to areas outside the space containing the furnace, the return air shall be handled by a duct or ducts sealed to the furnace and terminated outside the space containing the furnace.
Sorry I didn't read the instructions before initially posting the question.