[sepidpooy]

Hi Pros,

I am a new homeowner in the coldest State in the United State, Minnesota. My furnace is located in a CLOSET at the basement. There are three fresh air supply in that closet and I cannot manage to make our basement warm with all of these cold air intakes.

I was wondering if I can block the 3rd fresh air duct that is illustrated in the attached image ?

First fresh air supply is for Combustion Air Intake
Second fresh air supply is the duct that is connected to the return air supply of the furnace
Third fresh air supply is loose on the closet floor.

As you can see I have already blocked the 3rd fresh air supply but people keep telling me that it is not safe and I don't understand why. Some people telling me that it is not cost efficient but I have smart thermostats and it shows me I well run the furnace less frequently when the 3rd fresh air duct is blocked. I the duct into a bin and make the output shape like J but there was little or no impact.

There are only two hot air vent in the basement ceiling. In order to make the basement warm I have to close almost all upper level hot air vents to force most of the hot air come out from the basement. However, this 3rd fresh/cold air duct is just messing with the hot air right in the basement and does not let the hot air even warm up the basement.

The AirCycler does not control any vents. I believe all the vents are always open. AirCycle control just let me turn the Fan periodically. Something that my smart thermostat can do as well.

This is a fairly new house built in 2007 and it is very air tight. Infact I put some 3M window seals on the basement to even make it more tight.

 

[pecmsg]

You have a gas fired appliance that needs air for combustion. Open the vents, get a contractor to test (combustion analyses) the appliances to determine if outside air is needed!

 

[sepidpooy]

You have a gas fired appliance that needs air for combustion. Open the vents, get a contractor to test (combustion analyses) the appliances to determine if outside air is needed!

combustion air intake is right there directly attached to the furnace from the top. Am I wrong? Is there anything that I can do by myself since I cannot afford a contractor at this point right after moving to a new house.

 

[pecmsg]

combustion air intake is right there directly attached to the furnace from the top. Am I wrong? Is there anything that I can do by myself since I cannot afford a contractor at this point right after moving to a new house.

What about the water heater? ? ?

 

[sepidpooy]

What about the water heater? ? ?

Oops... I have missed that.

Does it really need fresh air from outside or can function safely with indoor air?
Can I just keep an open hole in that duct instead of completely opening it ? this will reduce the fresh intake cold air comming to the closet.

 

[kdean1]

Houses can provide air for combustion, but you have stated that your house is very tight. That may mean that your house does not have enough infiltration to provide the needed quantity of air. I do not recommend closing any of the ducts from the outside without testing the venting. Under no circumstances should you open the return duct in the mechanical room as it may very well overcome the draft for the water heater and dump all the venting for it into the house.
You really need a contractor who has been trained in combustion analysis and carbon monoxide. The National Comfort Institute website has a list of certified contractors who have such training.
Another aspect of your house is that the basement registers are in the ceiling. That's too bad as the heat never reaches the floor. Closing all the registers upstairs is likely to reduce the air flow through the furnace below what it needs to work properly. You may need to use some electric heaters for the basement until you can have a contractor propose a solution for both the venting and the heating.

 

[ammoniadog]

Hi Pros,

I am a new homeowner in the coldest State in the United State, Minnesota.

I think the cold may have gotten to your head and caused you to forget about a few of your fellow states. According to a quick Google search, Alaska and North Dakota are both colder than Minnesota is. Minnesota looks like it's essentially tied with Maine for 3rd place.

I'll give you a free pass if you happen to live in the Iron Range though, I know it gets damn cold up there.

As for the combustion air ducts, like others have said, they all may or may not be needed. Does your water heater use a PVC pipe for it's flue? That could be a good sign. At least then it would be less likely to back draft and kill you in your sleep than it would be if you had a standard water heater. I would definitely heed the others advice to get someone out there who knows what they are doing to let you know for sure though.

 

[teddy bear]

Oops... I have missed that.

Does it really need fresh air from outside or can function safely with indoor air?
Can I just keep an open hole in that duct instead of completely opening it ? this will reduce the fresh intake cold air comming to the closet.

This is what kills a 1,000 people a year. CO does not mess around. CO alarms are critical. What is the Temp/%RH in your home in the various areas of your home? Numbers of occupants? Size of the home?
Regards Teddy Bear

 

[ga-hvac-tech]

CO (carbon monoxide) is serious stuff...
Odorless, tasteless, colorless... no way to identify it..
Yet it is the silent killer.

Google 'carbon monoxide deaths' and read up...
IMO simply NOT worth taking a chance with...