Low airflow upstairs

Old 12-03-02, 09:35 AM
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Low airflow upstairs

This is a problem for us as the bedrooms upstairs are too cold in the winter and too hot in the summer. I've been told that this is a somewhat normal problem but appears to be extreme.

I checked the temperature difference and it is always 8 to 9 degrees cooler upstairs in the winter. That seems too much to me.

Can anyone tell me what difference in temperatures should be acceptable?
Old 12-03-02, 01:05 PM
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In a properly built house with a well designed HVAC system there should be no difference in temps.

If you post back with details about your location, house, heating system, etc, etc, etc, someone may have some ideas.
Old 12-03-02, 01:13 PM
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Like Greg said need more info here. Did I read right?The upstairs is to cool when the heat is on?????? Just where and what is your insulation???Does it help to put the fan on and let it run? ED
Old 12-03-02, 08:47 PM
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I'll post as much info as I can:

It's a cape cod style home with a basement. THe furnace is in the basement. There are two bedrooms upstairs (and a bathroom) and two bedrooms on the main level and the basement is unfinished. The main level is where the thermostat is and we usually set it to 70 degrees. The upstairs never reaches a temp above 62 in the winter and my girls upstairs think it is too cold.

I suppose we could turn up the thermostat to 76 or so but then it would be too hot on the main level.

Each upstairs bedroom has two vents. There is only one return for the upstairs and that is at the top of the stairs with a bedroom on each side of this hallway.

When the furnace is on, the airflow coming out of the registers upstairs seems much less than that of the main level registers. I have the main level registers closed as much as possible but this still does not help.

Adjusting the dampers in the basement where the duct work leaves the furnace does not seem as though it would help as each of the two main feeds send air to both upstairs and main level rooms.

Does anyone have any ideas as to how I can resolve this issue?

Thanks in advance for any help. Ed
Old 12-04-02, 05:39 AM
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It sounds as if there is not enough airflow to the second level.
You could check and make sure the furnace fan is set to its highest speed.

Ductwork changes may be necessary to correct this .

Is this a new house or did you inherit this problem?
Old 12-06-02, 10:41 AM
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Similar trouble

I have a cape cod, 60 year old home with a 1 year old furnace and a couple year old A/C. I can't say what the A/C will do, but I can guess. I just bought the place this month. I am in West Michigan, it is snowing outside and it will for at least 4-5 more months. Our son's bedroom is on the second floor and you can feel a slight "luke warm" draft coming out of his single vent in his room. There is a cold air return up there as well. Every room in my house has at least one vent. I'd say that the strength of the blower is up, because the main floor vents kick out the air like a turbo-prop. It just doesn't seem to make it above that floor.

Any ideas?
Old 12-06-02, 10:43 AM
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Similar trouble (cont.)

Just to add. On the main floor I closed every single vent in the house. The blower still forces air through them, and only trickles into his room.
Old 12-06-02, 10:50 AM
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I appologize if this is not the correct method, but here are the vent and return methods that my furnace has to work with. This one (of three pics) is the large vent in the living room. There is no way to close it. I went to Lowe's last night hoping to find a replacement vent that wood close, but saw none. Do they exist?
1 of 3
Old 12-06-02, 10:52 AM
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floor vent

I appologize if this is not the correct method, but here are the vent and return methods that my furnace has to work with. This one (of three pics) is the floor vent. There is one of these in every room of my house, except the living room. That one is shown in the other (1 of 3) posting.
2 of 3
Old 12-06-02, 10:53 AM
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cold air return

I appologize if this is not the correct method, but here are the vent and return methods that my furnace has to work with. This one (of three pics) is the cold air return. These are scattered around the house on the main and second floor. These are never covered nor can they be closed.
3 of 3
Old 12-06-02, 12:03 PM
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I'm sorry but pictures cannot be posted in these forums due to abuse.

For us to be able to see a picture you must post them somewhere else and provide a link.

Is it possible that there is a balance damper somewhere in the duct going to your son's room.
If you close all the other dampers you should get an increase in flow.
Old 12-06-02, 04:36 PM
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Air balancing is in need here! Do you have access to where the duct splits to send the air upstairs? There should be a damper blade to both sides. Running the fan will help warm the upstairs also. This will take mixed room air in the returns, and pump it to all rooms.
Old 12-07-02, 04:52 AM
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do you have a central duct that runs to the upstairs. if you do and it is insulated on the inside then some insulation may be loose and blocking the air flow.
Old 12-07-02, 05:54 AM
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poor design I think

I too live in a Cape in S. New Hampshire. The upstairs is always cooler & warmer than downstairs.
The problem(s) I've been told are as follows.
1. The 2nd floor return is 6" and is undersized to draw more air down which is necessary to push more air in.
2. The ductwork design is poor. The 2nd floor has 1 feed 4"x10" that is fed off of the 1st floor trunc.
3. The 2nd floor vents are in the ceiling and may not be well insulated or not taped properly and heat loss is occuring. I've never been in my attic as it's only a crawl space and no storage.

The remedies were 1) keep the fan blowing to circulate the air more. 2) Somehow increase the 2nd floor cold air return to draw the cold and hot air down. 3) install ceiling fans upstairs to assist in circulating the air -

Me, I just had installed a new Trane 90XR gas furnace, which replaced the original Air Ease 30 yr old system and I do notice a big difference upstairs with just the blower alone circulating the air.

Good luck.
Old 12-07-02, 03:08 PM
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I have the exact same problem in my house. It is also a cape cod. What we did was increase the air flow by adding a second duct to the upstairs branch. The way my furnacer was laid out it was relativly easy. THe only problem was finding an adpater to fit on the bottom of the duct leading upstairs. It increase our air flow by at least double if not more.
Old 12-09-02, 07:16 AM
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I'd like to know how you added the 2nd floor cold air return.

How much of a difference did it make? You say double but, do you feel more air coming out of the 2nd floor vents?

Did you do it yourself?

Please reply w/ details if possible.

My 2nd floor 6" round return is located at the top of the stairs right above the base board. It shares the space w/ an unlined 6" hot water exhuast/vent thru the roof.

Thanks in advance.
Old 12-09-02, 08:47 AM
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Question This is getting a little confusing!

"Legend" started this thread and was asked to provide more details.

"Melballs" responded with some construction details.

Are you the same person?

As I see it we have four people asking a similar question.

I'll speak to all of you:

Something that I see in residential home construction that is seldom a problem in commercial is bad duct design.

The normal scheme of things in commercial is that the entire mechanical / electrical system is designed by qualified engineers. They take responsibility for the satisfactory operation of the mechanical systems.
Because of that, ventilation problems are a rarity.

Residential on the other hand does not seem to do that and I think I know why.

Cost and knowlege.

Residential HVAC is deceivingly simple.
Homeowners will tend to trust their general contractor/ installer to design these systems when their qualifications do not necessarily make them good designers.

Ask your installer what the design CFM and FPM compared to the actual readings are.
Indepedant air balance testing of residential ductwork................unheard of.

Also, what homeowner wants to add 2k to the cost of the home?
I think ones that want a silent and effective HVAC system should.

Don't get me wrong, the majority of systems being put in are fine.
The only problem is that homeowners have no protection against what you are all experiencing.

Your problem:

I think that you all suffer from a lack of airflow.

To effectively correct the situation you must increase the volume of air to the second floor.
After checking for closed dampers and resricted ductwork, your only option would be to install additional ductwork.
Unfortunatly this would involve carpentry work as well, to open up a pathway for the duct to follow.

You likely have to connect to the main supply in the bsmt.

Search this forum for ductwork as there has been a lot of discussion on this topic.

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