How to increase air flow and comfort to cold rooms?

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Old 01-31-18, 10:43 AM
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How to increase air flow and comfort to cold rooms?

My family and I just moved into a 30-year-old house. The previous homeowner replaced the forced air system about 6 years ago. My 2 daughters have each their own room with a bathroom in between. Their rooms are very cold in the winter time. We have gas heat and a 2-stage air handler. One zone and no dampers anywhere, just the basic vent dampers. Also no return ducts in those rooms.

I thought that these rooms had a blockage and even bought a snake-camera connected to my phone (for video) and snaked the ducts - no blockage. What i did discover was perhaps unusual. The supply from the air handler goes from the main trunk directly to the bathroom (which receives plenty of air) then branches off on both sides to supply air to each room on both sides.

So I would like to know if there is a way to increase air to both rooms that doesn't involve ripping down drywall, disconnecting duct work and running new supply lines to the air handler.

Would like something like this work for my situation? HVACQuick - Suncourt HC500 Flush Mount Register Booster

Any suggestions on how to improve the situation would be welcome.
 
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Old 01-31-18, 11:00 AM
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Hi homer,
While we wait for the hvac pros (I"m not) I'll ask some questions.
Are these rooms over a heated basement or a cold space like a garage?
Have you checked the air flow into the cold rooms, hand test?
Are the supply registers close of distant from the furnace?

From my specialty I would look at the heat loss in those rooms. Is there an attic space above the rooms? Are those ceilings well insulated? On cold days do you feel any air leaks around the windows?

If you can see the plumbing for that bathroom from the basement has there been any effort made to seal all penetrations?

All for now.
Bud
 
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Old 01-31-18, 11:06 AM
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The basic operation of any forced system is the air flow in has to equal the air flow out.

If the rooms do not have return lined then the incoming air simply has no where to go.

If you want more air into the rooms you need to get an obstructive way to let it out!
 
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Old 01-31-18, 11:28 AM
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Changing duct work behind drywall is impossible without removing the said drywall. You could close off the bathroom register to see if that makes a difference. A return air duct to each room is a requirement. If you can't do that, make sure that the doors have the bottoms cut to allow for the supply air to escape as Mark1 stated. What area is below the 2 bedrooms? Is it a basement, living space or garage? Those fan/register things that you referenced may help. I have never had much luck using things like that.
 
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Old 01-31-18, 08:48 PM
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I'm not afraid to rip out the drywall, but if I can try some other technique first, I rather do that. I have a called a couple HVAC companies, it seems that most people want me to try running the fan from auto to on and raising the temperature to 72 or 73. We typically keep it around 68. I don't want to run the system too much and have an expensive utility bill, I guess I'm a cheapskate.

In the fall, when we moved into the home, I sprung to do some insulation in the attic. I hired a crew to add open cell spray foam to seal the attic. We also have Andersen windows in the entire house, a couple windows do leak around the edges, and I have mostly sealed up the cracks with temporary caulk.

The two bedrooms in our floor plan. are above the family room and living room. The air handler is in the basement, I should point out that the living room has two vents and an air return, it's the most comfortable room in the house as its directly over the system. I tried shutting the vent to the upstairs bathroom between the two bedrooms, but it made no difference.

The problem is that the vents for the bedroom have very faint air pressure coming out of them. I put my hand over the vent and question whether its even on. I'll put a tissue over the vent to check if its on.

Is it commonplace for the supply to branch off in 3 directions and feed multiple spaces with the single line?
 
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Old 02-01-18, 02:35 AM
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Have you looked at a mini split system, might be a lot easier than tearing up walls installing ducts and maybe improving heat / cool performance!
 
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Old 02-01-18, 07:23 AM
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It takes air pressure to make air change directions. At the point where they branch the pressure is already low and then the sir has to make the turn and move through smaller ducts, thus very little is getting to those rooms. Map out what you have to be sure any changes will actually improve the heating before you tear things apart. I'd have a couple of contractors give me proposals and listen to what they suggest, usually estimates are free.

Another good investment is an energy audit but be aware some are just a sales pitch where others are a comprehensive look at your home, hopefully including an Infrared Camera and blower door. I'm a retired energy auditor and know first hand what they are likely to point out. Makes for a better plan.

Bud
 
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Old 02-01-18, 08:33 AM
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Thanks for the reply, part of the problem is finding someone who would be willing to discuss reconfiguration of the ducts. Instead I have been getting responses from HVAC companies like this one:

The home's insulation has to be activated by the inside rather than the outside. The temperature setting at 68 degrees will not maintain any homes comfort. We suggest running the fan from auto to on is to circulate existing air to balance the home air flow and activate the insulation from the inside of the home. The raising or lowering the temperature a degree or 4 give you the opportunity to see what it really takes to have more consistent temperature in the home. You could also try closing a supply in the living room and
bathroom may help with the air flow. We have found that 95% of Customers run in AUTO mode!, while we recommend the fan run on.
We provide expertise in providing alternate products to achieve a rooms comfort. The decision you have to make is the budget for the renovation:
-- Adding ductwork can be $495 on up.
--Adding an alternative system $4000 on up.
--Circulating air with a furnace fan every evening about $20/month increase on the utility bill.
Hope this helps!
I was always told you shouldn't close off vents to rooms as it can lead to a negative pressure scenario, but instead use automatic dampers. Would adding dampers have any affect on my situation. Could I add a zone that would allow the temp to increase just to those rooms and closing the dampers on unused rooms?

At the point where they branch the pressure is already low and then the air has to make the turn and move through smaller ducts, thus very little is getting to those rooms. Map out what you have to be sure any changes will actually improve the heating before you tear things apart. I'd have a couple of contractors give me proposals and listen to what they suggest, usually estimates are free.
I like this approach. How would you be able to tell if the proposed solution would actually work without getting in there? Is there a specific HVAC specialty I can request?


One last question: (Since this is a DIY forum, )if you can imagine the duct supply goes up and then as a T-connector for both rooms. Would it be possible to modify the duct to cap off the position at the top so that air can only move to each side? I don't care about heating their bathroom.
 

Last edited by emshomer; 02-01-18 at 08:34 AM. Reason: quoting
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Old 02-01-18, 09:08 AM
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"and activate the insulation from the inside of the home" Then "We have found that 95% of Customers run in AUTO mode!, while we recommend the fan run on."
Cross them off of your list .

You said "I was always told you shouldn't close off vents to rooms" certainly not without considering other implications for doing so, like furnace performance and plenum temperature.

Zoning is difficult with forced air heat, balancing is what you want.

"How would you be able to tell if the proposed solution would actually work without getting in there? Is there a specific HVAC specialty I can request?"
Yes, here's a link. https://www.load-calculations.com/wh...manual-d-.html
And all manual references mentioned, D,J, and S, should be part of the skill sets that any HVAC contractor you deal with has, and more. Manual D would specifically address air flow and heat distribution.

Doing an actual design would be a challenge for a DIYer but learning more about what they do would certainly help explain some of your problem. I haven't looked but I suspect there are lots of links and videos discussing duct sizing and related.

To suggest modifications would need more information and pictures, and best if a pro steps in. I'll keep you busy until we catch their interest .

Do you know what size ducts are feeding those two rooms, smooth metal or flex ducts?
And pictures, pictures, pictures.

Bud
 
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Old 02-01-18, 05:39 PM
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Would it be possible to modify the duct to cap off the position at the top so that air can only move to each side?
The easiest option would be to install a vent with louvers and close it!

https://www.doityourself.com/forum/a...1&d=1517531938
 
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Old 02-02-18, 12:05 PM
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Thanks, all it sounds like the consensus is to get a qualified contractor in to see if they can balance the system. I appreciate all the feedback
 

Last edited by emshomer; 02-02-18 at 12:06 PM. Reason: thanks
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Old 02-02-18, 02:11 PM
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Im late to the party but Id try to find the duct that serves the bathroom at the main duct and add a scoop to try and force more air into it. You have one duct trying to condition 3 room's. You will never make it right unless you add a run for each room. but you might be able to get a few more cfm up to the rooms. As always two floors needs two systems. this is best practice HVAC.
 
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Old 02-07-18, 07:51 AM
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For some reason, every HVAC technician I have contacted insists I just turn the heat up. The problem isn't the temperature but the amount of air coming out of the vents. Nobody willing to peel back the drywall and get their hands dirty?

I know this may not be best practice and I'm probably going to make matters worse in the long run, but I had an idea that I wanted to run by the professionals. Could I add a round T-connector to join the two rooms and supply and totally cut off the bathroom? I could always run a supply to the bathroom later down the road, but running two supply lines and two returns to an existing house is a big job.

The bathroom is very small, and for the past 2 weeks, I have had the register closed there, and haven't noticed a major difference. I created some crude drawings of the proposed Idea. I'm thinking with the bathroom cut out of the mix, the air will be stronger coming out of the two-bedroom vents.


This is what my setup currently looks like:



This is what I am proposing

 
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Old 02-07-18, 12:02 PM
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e,
Air, just like water takes the path of least resistance. That is why your bathroom gets all the heat.

With that path of flow open the air has no reason to go to the other rooms.

By capping the bathroom supply it will at least force the air to the other pipes as it will have no other place to go.

If it will be enough only time will tell but it's better than what you have now.

As mentioned previously there should have been separate supplies but that ship has sailed unless you rip everything out which is a huge job and then do you even have enough room to run separate supplies.

A lot is going to depend on the amount of air going into that trunk and the size of the trunk.

If airflow is weak from the start then nothing you do will matter until you increase the airflow.

They did make booster fans that get installed inside the trunk to increase airflow and get wired right into the blower circuit of the air handler so when the blower runs so does the booster fan.

If you have access to the beginning of the supply trunk line of this branch you can install the B.F. and leave things as they are if you need the added air.

I would start by capping off the bathroom. It will not hurt anything and it cannot get any worse and would force the air to the other rooms which may be enough.

Just a thought, hope this helps a little.
 
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Old 02-07-18, 12:40 PM
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Thanks for your reply...

If airflow is weak from the start then nothing you do will matter until you increase the airflow.
Airflow to the bathroom is pretty strong but I could look into the booster fan, I think a couple people have mentioned this.
 
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Old 02-07-18, 12:47 PM
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Last year called the service guy with a problem. Turned he replaced the blower fan, I kept the old one. When out of the furnace you couldn't turn the motor shaft by hand so I suspect low air flow was causing my cycling problems. New fan worked great.

But, I applied a touch of spray lube to each end of the motor on the shaft and it spins very easily. I have another use for it but had i known I'm sure it would have gotten a touch of oil rather than being replaced.

Bud
 
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Old 02-07-18, 01:10 PM
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No dampers kind of puts you at a disadvantage with the balancing of the system but something else to consider is that your unit must have a multi speed blower which you may be able to increase if needed.
 
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Old 02-07-18, 02:03 PM
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A booster fan will not work. You have to have the air on the entering side of the fan for it to be able to move the air. You don't have the air available because the duct is two small.
 
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Old 02-10-18, 05:30 AM
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First let me make a comment; most HVAC people have no idea how to size and install a good duct system or won't because of cheap competition . Now, this is what I have done in my house and it has worked for me.I have by trial and error been able to adjust my duct system to give me a fairly comfortable temperature in my whole house. Do not be afraid to close off registers in or near rooms that are warmer than others. My house is a 1 story 2000 sq. ft. with another 2000 sq. ft. finished basement.I have supply and return registers in every room, so closing a register in 1 room does not mean that room will be cold, just cooler since the return is still open bringing warm air into that room. The thermostat is in the central area and I keep some of the registers in that area closed so the the furnace will run a little longer to allow the heating system to push more heated air into other rooms. I run the furnace fan 24/7 to help keep all the rooms the same temperature. I have done it this way for 40+ years in 3 houses. I have never had any fan motor issues or replaced fan motors. Yes, it may be more expensive to operate this way but it is comfortable You know the saying "happy wife, happy life", so it is worth every penny. My furnace is a 2 stage heat, so the fan runs on a low speed for continuous air and 1st stage heat, medium speed for 2nd stage heat and high for A/C. I would try closing some registers to see if this helps, however you can't fix a poor duct system just by closing some registers.. Oh, by the way do not worry if you can barely feel air coming from some of the registers. most of mine have very little air flow that you can feel. If you ever find a great HVAC guy make sure that you always use him only since good ones are hard to find.
 

Last edited by Steamboy; 02-10-18 at 05:31 AM. Reason: more info
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Old 02-12-18, 07:09 AM
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Thanks for the replies, I tried doing what @steamboy suggested closing registers, but rooms were very cold within 24 hours. Lacking cold air returns is probably contributing to the problem.

So I finally had a couple HVAC reps out to give me their assessment. One guy insisted I needed to add a complete new system for the upstairs, while another said I could get by adding another 2 or 3 zones to the house. They both insisted that no way in hell are my ducts configured in the way I drew my diagram and that they counted the number of ducting off of the trunk and then went around the house to count the vents to make sure they matched up.

I'm confident that adding another system would probably fix the issue, but I don't want to take on such a large purchase having not lived in the house more than a year.

The one who suggested adding another zone -basically said it would involve either wiring in another thermostat ( I use Nest) or going the wireless route and using Honeywell's wireless thermostats. The all in price tag was $2800 for adding an additional 2 zones to my single zone home and this would take about a day.

He was pretty confident this would be the solution to go with. However, I'm not confident this would make a noticeable difference and I'm more concerned about the buildup of static pressure and how that will affect our system in the long run.
 

Last edited by emshomer; 02-12-18 at 07:14 AM. Reason: grammer
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Old 02-12-18, 10:09 AM
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Back in post #6 Marq1 suggested mini-splits. Again that sounds like an ideal solution. There are heat pump units that can heat and cool and some can run multiple rooms (up to 8, I think on very large ones) on a single outdoor unit. I added mini-splits in a family room and master bedroom several years ago for cooling but have used them occasionally as well for heating to supplement the main house system.
 
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Old 02-12-18, 10:45 AM
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Back in post #6 Marq1 suggested mini-splits. Again that sounds like an ideal solution. There are heat pump units that can heat and cool and some can run multiple rooms (up to 8, I think on very large ones) on a single outdoor unit. I added mini-splits in a family room and master bedroom several years ago for cooling but have used them occasionally as well for heating to supplement the main house system.
Thank you. Is that the same thing as ductless heating? where a unit is installed on the wall in each room?
 

Last edited by emshomer; 02-12-18 at 11:04 AM. Reason: quote
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Old 02-12-18, 03:12 PM
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Yep...Mini-split, ductless--same thing. Make sure it is heat pump though for heating in addition to cooling.
 

Last edited by 2john02458; 02-12-18 at 03:13 PM. Reason: heat pump
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Old 02-12-18, 08:49 PM
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Ducted mini-split systems exist.

I have an upstairs room that was very hot in summer; it was an addition by a previous owner and my central air couldn’t cool it. I tried the electric register boosters mentioned in the first post; I found them noisy and ineffective.

I ended up installing a ductless mini-split. It works well and is quiet. Ducted would have provided better air flow, but would have been a much bigger job.
 
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Old 03-22-18, 03:30 AM
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I am curious "emshomer", did you ever get the heating problem corrected for your 2 bedrooms? Have you tried running the fan 24/7, increasing the fan speed, or any of the other suggestions guys have made. You never said how many return air grills you have or if there is just 1 or 2 that are centrally located. If they are centrally located do you have about 1 1/2" free opening at the bottom of the doors in the rooms with out return ducts? Before I would rip out walls or buy the "perfect system" most HVAC companies boast about, I would ask if they could add returns where there aren't any and/or fix the duct work to supply more conditioned air to those rooms.
 
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