Is the lack of airflow in your 4-level split home related to the strange things on the pipes in the basement, despite trying various solutions like cleaning ducts and using register booster fans?
Asked by Alma Møller 
5 months ago
Last Updated: April 22, 2024
We have a 4 level split with central air heating, but the air doesn’t seem to reach the bedrooms on the fourth level. The basement gets really hot in the winter and freezing cold in the summer, which feels like a waste of energy. We’ve tried cleaning the ducts, getting a new furnace filter, closing vents, and even using register booster fans in the kids’ rooms, but nothing seems to work. I noticed some strange things on the pipes in the basement. Could this be causing the issues? I didn’t see anything mentioned during our home inspection. Any advice would be greatly appreciated.
For the rectangle one it’s a bit tricky to say, that might be an air intake, so that *could* be fine, but if air is coming out of it then it will need to be sealed. As for the others, it seems like someone amateurishly tried to cover the air ducts with foil and duct tape (?!) which is now letting air escape due to holes that have formed. You can purchase proper pipe end pieces at home depot, or at least redo it with real metal tape so it doesn’t rip and leak like that. It might be a good idea to have an HVAC professional come in and inspect the system.
You should definitely ask for a refund for your home inspection. It’s so obvious that they missed something wrong. I had a home inspector who completely missed a disconnected air duct pipe hanging loose in the crawl space, among other issues, and I got a refund.
Do you think the two smaller ones (covered in tinfoil) are definitely blowing air out? Should those be closed off properly? I can’t quite tell about the rectangular hole. When I put my hand in there, I feel air flow, but it seems like it’s blowing away from the furnace. I need to inspect that further to be sure.
Is it something like this that would need?
Yeah, that sounds about right. Measure the dimensions, snap some photos, and you should be able to locate the items you require in the store.
This is completely normal.
Based on the shoddy appearance, a previous homeowner decided to expand the HVAC system and incorporate basement air vents. Is the large rectangular opening in a return or supply duct (does air flow out, or draw in)? Give the fan a whirl to check, no need to fire up the furnace. It might be wise to consult an HVAC professional to maximize your system’s performance.
Random thought: Perhaps there is a duct rupture that is releasing the air you desire into the walls, attic, or elsewhere.
Are all the ducts partially taped and with a square hole cut out? If that’s the case, it’s important to seal them all up.
Hey, did you know that square hole might actually be a return intake? If it is, blocking it off would not be a good idea at all.
I think the two smaller vents covered in tinfoil are definitely pushing air out, so I’m assuming they need to be sealed off properly. As for the rectangular hole, I can’t really tell. When I put my hand in there, I can feel a slight breeze and it seems to be moving away from the furnace, but I’ll have to investigate further to make sure.
By simply closing a few basement vents, , you can actually boost the air pressure going to the rest of the house.
Did you try installing dampers to partially close the lower ducts and redirect more air upstairs? We faced a similar issue and using dampers really helped in balancing the airflow throughout the house.
We haven’t tried that approach. We’ve only closed the vents.
Hey , I’ve struggled with the same problem of balancing my system. I attempted closing vents with no success. But when I installed two dampers, it made a huge difference.
Can you explain what a damper is and where it should be installed?
It’s basically a small door/flap that is installed in either the main line or the runs (lines leading off the main line to a vent) which you can open or close to regulate the airflow to that vent. It helps to direct air further along the main line to areas that may not be receiving enough.
Look up “damper” on Google, select IMAGES. You’ll quickly grasp the concept of dampers and how they function. NWR – No Words Required. BTW, great question. When in doubt, ask. That’s what makes this group so special.
As a home inspector who specializes in air and duct infiltration, the fact that your house has 4 levels indicates that the duct system may have been installed in a haphazard manner. Duct booster fans won’t be effective if there isn’t enough pressure in the ducts to distribute conditioned air to the rooms. The patched holes and taped pipes suggest a previous DIY attempt, but the large rectangular hole could be an air intake. However, if the ducts are sealed in the basement, the return air it’s pulling may not be conditioned. Consider getting a duct blaster test done by a local professional to assess the situation and seek advice from an HVAC expert to inspect the system.
That’s where you begin – with a skilled professional who knows their stuff. The entire system must ensure proper circulation of supply and return air.
It’s a good idea to have the entire system pressure tested and inspected with a camera. There could be a blockage or break somewhere. Also, check your returns and filter to ensure there are no clogs. If the ducts and returns are in good condition, the issue is likely that the system is underpowered. Contact local HVAC companies to get estimates on upgrading to a more powerful blower, ideally with variable speed. Adjust the lower vents. You can purchase a handy wind speed gauge on Amazon for under $40 now, which you can use (along with some simple home science/engineering) to measure and regulate the vent airflow in each room for optimal system efficiency. They can also be used to measure the returns, professionals use them to diagnose various problems and solutions.
Did a qualified HAVC systems engineer ever evaluate this place? How big is your house in terms of square feet? Also, what’s its cubic feet size? Can you tell me how many windows, doors, and rooms you have? How about the number of rooms on each level? I wonder if every room is properly vented with at least one supply and one return vent. Keep in mind that the air won’t flow correctly if it can’t be pulled out of a space. There’s a limit to how much air a system can move. What’s the deal with the hole in the basement? Is it on the supply side or the return side? I have a hunch that whoever installed your system only knew how to hang ducts. Your system seems out of balance with too much flow near the furnace blower and not enough at the other end. Most of the air flow might be stuck in the basement and first floor, leaving the upper levels with little to zero movement. To check your system, try using a sheet of standard writing paper while it’s running. Hold the paper to each vent and see if the air can lift it up and make it wave like a flag. If the paper barely moves or doesn’t move at all, you’ve got an issue. Try this with all the vents and note any differences.
I really enjoy the hands-on problem-solving and clear explanations. And yes, it’s just the beginning but a clever one.
Your advice is way more helpful than just saying something is off… maybe an issue with air distribution… Great pointers there buddy.
I really appreciate your help! No, no one else has taken a look aside from the home inspectors who clearly overlooked a few things 🤔
Remember not to completely shut vents, as it can cause the unit to freeze up and work inefficiently! Many people misunderstand this unless they know about static pressures and duct testing. It seems like a DIY project that might leave you guessing. A large hole is most likely a return air vent, while blocked vents that aren’t balanced can create too much pressure and hinder the proper airflow of the system.
One house we bought had a furnace that wasn’t the right size for the finished lower level, even though it was sold as such. I think it’s best to consult with an HVAC professional.
It’s a bit tricky to figure out what you’re showing here. Are those duct ends capped off and with holes in them? They actually make sheet metal caps for that purpose if the duct should be closed off. Have you checked for balancing dampers? You can usually find them as small metal handles on the side of ducts, with butterfly/flap dampers behind them to help balance the system. They should be easily accessible, like in the basement near the furnace or in the attic. Adjustable registers can also assist in balancing the airflow, similar to dampers. The basement registers typically remain more closed compared to those on upper floors. It looks like you have leaks and holes that need attention. That rectangular hole – any idea what that’s for? Cover it with a piece of sheet metal and secure it with screws. Start by fixing the obvious leaks and then proceed from there. You can use the flow test method mentioned by someone else to quickly check for issues. Do you have ducted return or does the air just flow down the hallway to a central point or grill? There’s a lot to investigate and uncover here. I always refer to it as sleuthing out problems. Hopefully, you’ll learn something new about your home and HVAC system – it’s all part of the process! Good luck!
Air tends to follow the easiest route, so I suggest sealing all of those areas and keeping a small duct open in the basement.
When you go upstairs, check for dampers that are closed (wing nuts are a good indicator). Also, improve the sealing of basement vents and ensure that the upstairs rooms have unblocked or open returns.
You’ll want to have a velometer on hand.
Now, place that paper over each air return while the system is running. There should be at least one in every room. The paper should be firmly sucked to the vent, making it hard to move. Pay attention to whether it changes with doors open or closed. If the paper easily moves or doesn’t stay sucked to the return, there’s a problem. Next, close off the vents and returns to the lower two levels. Does the air flow improve on the upper levels or stay the same? If it improves, your runs could be too small or too long, or your system may be out of balance. If nothing changes, it could mean the upper levels are not connected or there’s a break in the run or the runs are too long. This test isn’t perfect but it can give you a general idea of the issue. Consider reaching out to an HAVC company that specializes in larger multi-level homes to get a properly designed and installed system. Best of luck.
Hey there, I’m Scott Bot.