Go Back   DIY Chatroom Home Improvement Forum > Home Improvement > HVAC

CLICK HERE AND JOIN OUR COMMUNITY TODAY...IT'S FREE!

Reply
 
Thread Tools Search this Thread Display Modes
Old 08-19-2013, 03:09 PM   #1
Member
 
Join Date: Aug 2013
Posts: 45
Share |
Default

Return Air in the basement


Hi all,

I recently purchased the house with central AC and heating in the basement and 1st floor. The return air is in the utility room which has a furnace and boiler in the basement.

There is a small opening (6 by 6 inch) in the utility room in the basement to take fresh air in. There is no other source of fresh air in the basement. I feel the air is too stale in the basement.

I asked one HVAC contractor on how to improve the air quality of the house, especially the basement.

His suggestion is to move the return air to the 1st floor so that better quality air can be supplied to the ducts. He also frightened me that I may have Carbon Monoxide problem when return air takes in the air from the furnace and boiler when running at the same time.

Does his suggestion make sense? Thank you all.

kgkg is offline   Reply With Quote
Old 08-19-2013, 05:25 PM   #2
Member
 
Join Date: Oct 2009
Location: Nebraska
Posts: 2,362
Default

Return Air in the basement


Return should never be taken from the same room as a gas furnace,water heater or boiler unless they have their own combustion air piped from outside. It can and will cause the flues to back draft,spilling carbon monoxide into the room. The return then sucks it up and distributes it through the house. That's why codes forbid it.

Fresh air would be outside air ducted to the return.

Post a couple pictures if you can.

Marty S. is offline   Reply With Quote
Old 08-19-2013, 07:49 PM   #3
Member
 
Join Date: Aug 2013
Posts: 45
Default

Return Air in the basement


Quote:
Originally Posted by Marty S. View Post
Return should never be taken from the same room as a gas furnace,water heater or boiler unless they have their own combustion air piped from outside. It can and will cause the flues to back draft,spilling carbon monoxide into the room. The return then sucks it up and distributes it through the house. That's why codes forbid it.

Fresh air would be outside air ducted to the return.

Post a couple pictures if you can.
Thank you, Marty. My next question is whether the return can be installed at my 1st floor, while all the coils & blowers, central humidifier, furnace, boiler are located in the basement.
kgkg is offline   Reply With Quote
Old 08-19-2013, 08:00 PM   #4
Retired from the grind
 
gregzoll's Avatar
 
Join Date: Dec 2006
Location: Midwest - Central Illinois
Posts: 14,126
Default

Return Air in the basement


Quote:
Originally Posted by Marty S. View Post
Return should never be taken from the same room as a gas furnace,water heater or boiler unless they have their own combustion air piped from outside. It can and will cause the flues to back draft,spilling carbon monoxide into the room. The return then sucks it up and distributes it through the house. That's why codes forbid it.

Fresh air would be outside air ducted to the return.

Post a couple pictures if you can.
You know, that is kind of hard, when most basements that are unfinished, or the water heater & furnace are in a laundry area in the basement and have at least a min. of two returns in them, and usually the Water Heater & Furnace get make up air from the house.

Really if the house is so air tight, that the returns are not the real cause of poor intake to the gas appliances like the furnace/boiler or water heater, it would be that there is no natural air coming into house for fuel burning appliances to have combustion air.

Even with 95% plus appliances, you could still have the returns in the basement, and no make up air, it is not going to cause CO spill over, there would be other reason that could cause it.
__________________
Ren: Now listen, Cadet. I've got a job for you. See this button? Ren: Don't touch it! It's the History Eraser button, you fool! Stimpy: So what'll happen? Ren: That's just it. We don't know. Maybe something bad, maybe something good. I guess we'll never know, 'cause you're going to guard it. You won't touch it, will you?
gregzoll is online now   Reply With Quote
Old 08-19-2013, 08:42 PM   #5
Member
 
Join Date: Aug 2013
Posts: 45
Default

Return Air in the basement


Quote:
Originally Posted by gregzoll View Post
You know, that is kind of hard, when most basements that are unfinished, or the water heater & furnace are in a laundry area in the basement and have at least a min. of two returns in them, and usually the Water Heater & Furnace get make up air from the house.

Really if the house is so air tight, that the returns are not the real cause of poor intake to the gas appliances like the furnace/boiler or water heater, it would be that there is no natural air coming into house for fuel burning appliances to have combustion air.

Even with 95% plus appliances, you could still have the returns in the basement, and no make up air, it is not going to cause CO spill over, there would be other reason that could cause it.
Hi Gregzoll, can I just run an exhaust fan in mild weather from time to time to refresh the air in the basement? This is definitely much easy to do and cost much less. The only window in the basement is within 10 feet of the furnace, and I have to install the fan there. Do you foresee a problem?

Thank you!
kgkg is offline   Reply With Quote
Old 08-19-2013, 09:30 PM   #6
Retired from the grind
 
gregzoll's Avatar
 
Join Date: Dec 2006
Location: Midwest - Central Illinois
Posts: 14,126
Default

Return Air in the basement


No, because that will not be the right way. You do not want to pull air out of the house, you want to insert air, if it comes back that your home is so air tight, that you need make up air.

Most homes leak enough, that you do not need a way of bringing in make up air. You really need to do a Blower Door test, to have the home checked out for how air tight it is. Most utilities will do it for $25-50 and credit to your utility bill.

My house still leaks enough in the basement area, that even with the R-13 around the joist bays and sill plate area, I still get enough air exchange from that, and due to some other cracks along the floor, that the house has enough make up air for my older home.

You can easily tell how air tight a home is, by if it retains smells for a very long time, the house stays musty even after the air is running, you get smoke blowing back at you at the exhaust for the water heater, etc.

There are a lot of simple tests you can do to check for air leaks on the house, vs. paying someone to come in and do it, unless you are doing it to add more insulation and seal around windows & doors, since it is easier to do that, then spending a few weekends doing the sealing around windows, adding door stop seals and weather stripping around doors, putting up insulation in the basement, adding to the attic along with sealing any gaps from pipes & wires penetrating the attic area.
__________________
Ren: Now listen, Cadet. I've got a job for you. See this button? Ren: Don't touch it! It's the History Eraser button, you fool! Stimpy: So what'll happen? Ren: That's just it. We don't know. Maybe something bad, maybe something good. I guess we'll never know, 'cause you're going to guard it. You won't touch it, will you?
gregzoll is online now   Reply With Quote
Old 08-19-2013, 09:42 PM   #7
Retired from the grind
 
gregzoll's Avatar
 
Join Date: Dec 2006
Location: Midwest - Central Illinois
Posts: 14,126
Default

Return Air in the basement


I got tired of my basement windows leaking so much through them, and raising the humidity and temp, due to they are the old original casement windows, that are over 70 years, I went and placed foil faced foam in the opening, with the foil facing outwards, to reflect the sun on the South, West sides, since they get the most direct sun, the window on the North placed the foil out also, since I have a roll up shade over those windows.

Went through and also caulked around the seams, to stop any leaks around the edges of the foam, then went through the basement and calked & foamed any gaps around where wood meets concrete block.

I found a large difference after doing that, that the basement temp lowered by at least ten degrees, humidity went down by also 15 to 20 points. Started with one supply vent in the trunk, and watched what happened. Went and added one return down there, made a better difference. When I started my Kitchen remodel, took the duct from the floor in the Kitchen, and ran that to the opposite side of the basement over the laundry area, which then made a huge difference in the basement temp. Just this year I added a second return vent down there on the back side of the house, did bring the humidity down by about four points, temp stays the same.

I can tell when we are not running the a/c, that it will start to get musty down there, so we run a pillar fan down there for a while, to move the air, and it clears things up. I can usually find one or two spots now that I have not sealed, due to feeling cold air during the Winter, which I have left a couple of spots for air to still seep into the house, and also allow for the house to still breathe.

Only thing I have left on my place is insulating the walls on the house, and add some more insulation to the attic, but what I have done over the past ten years has made a huge difference. It is just think as the house, and go around looking for problem areas. I found the largest problems was when the original owner had the retro-fit windows put in, the installers from Sears did not put any insulation around them, so I used DAP foam to seal around. Made a large difference in cold and warm air coming in.

One site that gets a lot of reference on this subject, is the Building Science . Com website which I have learned a lot from, in how to get the house to where you are not burning a lot of utilities to heat or cool, but you are not making the house sick, from making it too air tight, by finding a happy medium.
__________________
Ren: Now listen, Cadet. I've got a job for you. See this button? Ren: Don't touch it! It's the History Eraser button, you fool! Stimpy: So what'll happen? Ren: That's just it. We don't know. Maybe something bad, maybe something good. I guess we'll never know, 'cause you're going to guard it. You won't touch it, will you?
gregzoll is online now   Reply With Quote
Old 08-19-2013, 10:08 PM   #8
Member
 
Join Date: Aug 2013
Posts: 45
Default

Return Air in the basement


Hi Gregzoll, wow, you have done so much for your house. One naive question, what is "insert air" and "make up air"? I am a first-time homeowner and do not have much knowledge about it.
kgkg is offline   Reply With Quote
Old 08-19-2013, 10:52 PM   #9
Retired from the grind
 
gregzoll's Avatar
 
Join Date: Dec 2006
Location: Midwest - Central Illinois
Posts: 14,126
Default

Return Air in the basement


Make up air, is either using a 4" pipe to bring outside air through natural venting, with a auto damper, or using a J at the bottom, near the Water Heater, so that it can pull in air needed. You can also use something like this http://www.alpinehomeair.com/viewcat...categoryID=381 which is the way I would go, if I was putting in a way to bring in fresh clean air from outside. Of course stuff like exhaust fans over the stove and in bathrooms, would have to have a relay to turn the unit on. Same goes for when running the dryer.

Insert air, would be pretty much leaving the door open, or Windows, and not having any way to stop it, other than closing said window or door. or using the above method.

As for my place, yep, it has taken a lot to figure out the problem areas. We were having issues with our front entry closet growing mold in there. Figured out that there was a gap at the bottom, that was allowing air to be pulled in, which when the door was closed, it allowed the humidity in there to go up, along with when the furnace ran for a/c, it was also sucking in air from the closet, causing humidity and temp level to rise.

I ended up cleaning all the mold in there off the walls, with Concrobium Mold Control on the spots that had the mold, http://www.lowes.com/ProductDisplay?...llow&cId=PDIO1 and putting a Damp Rid container in there. I have so far gotten about 3/4 cup of water in the container, from the past six months that the container has been in there.

Closed up the problem gap with some 1/2" foam core gap sealer, and that has seamed to help. Normally our house stays around 46 to 50 rh upstairs, 49-60 rh downstairs depending on if the a/c is running or not. Temp in the house stays around 68-72 all the time, unless we turn off the a/c, then maybe up to 74, before we get to where we close up the house and run the air around 71.

I did have a attic power ventilator installed in the attic, which has helped to keep the attic cool, and also has helped to find spots downstairs, where air was being pulled up into the attic, and a couple of other spots.

Older homes are great if they have been maintained, but can be a can of worms, if the previous owners did not take care of them. Then those like myself come along and start tightening them up, fixing problems, and end up making it too tight, so have to go a step or so back, so that I did not have to invest in the air exchanger.

Get the blower door test done, find out where the problems are, how easy to fix, or how hard, then go from there. I know that one of the local insulation companies in my area, when they do the first blower door assessment, will do another after they are done, and the difference is what determines how much the costs are to fix the problems, and you get the utility rebates up front for both the city owned utility that does power, sewer, water, and Ameren Illinois who supplies our gas.
__________________
Ren: Now listen, Cadet. I've got a job for you. See this button? Ren: Don't touch it! It's the History Eraser button, you fool! Stimpy: So what'll happen? Ren: That's just it. We don't know. Maybe something bad, maybe something good. I guess we'll never know, 'cause you're going to guard it. You won't touch it, will you?
gregzoll is online now   Reply With Quote
Old 08-20-2013, 05:43 AM   #10
An old Tradesmen
 
Join Date: Oct 2008
Location: PA
Posts: 25,055
Default

Return Air in the basement


Quote:
Originally Posted by kgkg View Post
Hi all,

I recently purchased the house with central AC and heating in the basement and 1st floor. The return air is in the utility room which has a furnace and boiler in the basement.

There is a small opening (6 by 6 inch) in the utility room in the basement to take fresh air in. There is no other source of fresh air in the basement. I feel the air is too stale in the basement.

I asked one HVAC contractor on how to improve the air quality of the house, especially the basement.

His suggestion is to move the return air to the 1st floor so that better quality air can be supplied to the ducts. He also frightened me that I may have Carbon Monoxide problem when return air takes in the air from the furnace and boiler when running at the same time.

Does his suggestion make sense? Thank you all.

Move the return to the upstairs.

A basement should not have a return unless it has a supply of the same size in CFM.

A return in a basement without a supply can back draft a furnace/boiler or water heater. It can also often be the cause of the higher humidity when it causes the back draft. As the combusted air is is high in moisture content.

If you have a 20 foot long room with a 1" sq hole in both ends of it. And a return on one end of the 20 foot length. The hole closest to the return will have more air coming through it then the further one. Same happens with a return close to the furnace or water heater.

Perfect combustion, is a ratio on 14 cu ft of air to 1 cu ft of gas. Modern appliances still can't do perfect combustion, so excess air is needed. So if your appliances have 50% excess air for combustion. Thats 21 cu ft of air for every cu ft of gas they burn. So if a 60,000 BTU furnace and a 32,000 BTU water heater are both running at the same time. They are using 32 CFM of air. With a return taking out more air then a supply is putting in, it doesn't take long to back draft.
__________________
When posting in certain forums, knowing your location will help others give better feedback/advice/solutions to your questions.
beenthere is online now   Reply With Quote
Old 08-20-2013, 11:19 AM   #11
Member
 
Join Date: Aug 2013
Posts: 45
Default

Return Air in the basement


Hi all, I have one HVAC guy come over to see how he can move the return upstairs. He found that when air is rushing into the basement through the bottom of the door that leads to the staircase to the basement. His suggestion:

1. Don't move the return upstairs. If the return is upstairs, I cannot pull air into the basement, then the basement will have stale air.

2. Add an opening between the walls of the basement staircase and 1st floor wall so that more air can come into the basement.

3. Close off the utility room and move the return outside of the utility room, but the return still stays in the basement.

Does anyone think his suggestion makes sense? Thank you all!
kgkg is offline   Reply With Quote
Old 08-20-2013, 11:58 AM   #12
Member
 
Join Date: Jan 2013
Location: Southeastern MA
Posts: 1,388
Default

Return Air in the basement


Why not add a return to the first floor and move the current one outside of the utility room. Your HVAC contractor should be able to do the math to determine duct size.

Roughly how many square feet is the first floor and basement? What part of the country are in you in?
__________________
Dan
djlandkpl is online now   Reply With Quote
Old 08-20-2013, 03:02 PM   #13
Member
 
Join Date: Aug 2013
Posts: 45
Default

Return Air in the basement


Quote:
Originally Posted by djlandkpl View Post
Why not add a return to the first floor and move the current one outside of the utility room. Your HVAC contractor should be able to do the math to determine duct size.

Roughly how many square feet is the first floor and basement? What part of the country are in you in?
My first floor is 1000 square feet, and basement is 650 square feet. I am in New York city.

If I have two returns, will the system pull the same amount of air from each return?
kgkg is offline   Reply With Quote
Old 08-20-2013, 03:46 PM   #14
Member
 
Join Date: Jan 2013
Location: Southeastern MA
Posts: 1,388
Default

Return Air in the basement


Quote:
Originally Posted by kgkg View Post
My first floor is 1000 square feet, and basement is 650 square feet. I am in New York city.

If I have two returns, will the system pull the same amount of air from each return?
Your HVAC contractor can balance the returns for airflow. One of the HVAC pros should swing by tonight to fully answer your question.
__________________
Dan
djlandkpl is online now   Reply With Quote
Old 08-20-2013, 04:11 PM   #15
An old Tradesmen
 
Join Date: Oct 2008
Location: PA
Posts: 25,055
Default

Return Air in the basement


If your appliances are getting their combustion air from the basement, the air won't get stale.

Move the return to the upstairs.

__________________
When posting in certain forums, knowing your location will help others give better feedback/advice/solutions to your questions.
beenthere is online now   Reply With Quote
Reply


Thread Tools Search this Thread
Search this Thread:

Advanced Search
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Similar Threads
Thread Thread Starter Forum Replies Last Post
Basement return duct jagmandan HVAC 5 05-29-2012 09:18 PM
cold return and heat vents in basement gaetz1 HVAC 1 02-24-2011 07:56 PM
Return air for the basement swoop HVAC 4 01-18-2011 04:14 AM
basement causing suction on basment door BlueBSH HVAC 3 06-08-2010 02:26 PM
Basement return air ducting - flex or metal? BasementVirgin HVAC 5 10-29-2009 12:01 PM




Top of Page | View New Posts

Copyright © 2003-2014 Escalate Media. All Rights Reserved.