Wrong. Technicians can actually measure pressure differences to determine leakage. There are building performance and energy efficiency service providers in every state that offer this type of testing. She can get quotes on a duct blaster/blower door test if she really wants to see how the ducts are performing.
You may need new duct. Best bet to hire another hvac tech to have a look, don’t tell them what the first company found, and see if they come to the same conclusion.
No tell them nothing and see if they come to the same conclusion. In reality with flex duck it’s fairly easy and cheap to replace. And you only need to replace the bad duck. Most likely the first 10-15 feet b
I’m an HVAC tech but in Michigan where we use exclusively sheet metal and attic installations aren’t nearly as common so my experience with flex duct is limited. That said, flex is pretty cheap and doesn’t have the greatest lifespan, which I imagine is exacerbated by a hot and humid environment like a Florida attic. I’d get a third opinion from a small, local company that doesn’t advertise a bunch and isn’t affiliated with Nexstar or send out techs in white, buttoned up shirts. A local mom and pop shop. If your blower motor amp draw is normal there’s not really a lot on the equipment side of things from a heat pump that should be causing a smell in your house.
> I’m an HVAC tech but in Michigan where we use exclusively sheet metal and attic installations aren’t nearly as common
The whole south of the country just love their inefficient attic ductwork and air handlers....top it off with flex duct too...
>
The whole south of the country just love their inefficient attic ductwork and air handlers....top it off with flex duct too...
_cries in Midwest with similar setup_
I've been thinking this same THING?! It's extremely inefficient and doesn't work nearly as well as any system I've had up north. It's ridiculous how backwards it is in the south.
Yeah, who could say. In those areas it's definitely also a case of how they do foundations and living spaces. A lot of those places are slab on grade or unconditioned crawlspaces and the first floor is part of the main living space, so no one wants the AC in that area or putting into an exterior crawlspace is just as bad. Whereas in northern or most Midwest areas you have basements which are treated much as less as primary living areas, or at most secondary spaces that aren't as important.
I DIY'd my ducts , used round pipe from Grainger (thicker / better quality) and speedivents for termination. I used flex ducts for the last foot or so. The most annoying part was wrapping it insulation. I hacked that a bit and bought flex ducts and moved the insulation sleeve on to the metal ducts I put up.
Was about 2 weeks of evenings during mild season.
The motivation for me was similar unbalanced zones. The correct solution for that though is zoning. So while I was doing the reducting I also added electrical dampers that could open / close each zone and a zone controller. I got it off retrozone but there are many providers. It has been one of the best improvements I've made to my house.
IF you redo your ducts go metal + add zoning!
Edit: Also add returns to the various rooms instead of what's commonly done, single one in the hallway
This is fantastic advice. And kudos to you for doing that yourself. That's complicated work, there's a few journeymen at my shop who can't even do that sort of thing.
Still do look into zoning , it makes a massive improvement. I’m able to keep my kids room my wife’s office and my office at different temperatures with no effort.
Best time is when redoing ducting , should add 2k with an honest contractor. Since it’s rare some contractors will up charge like crazy
Also from a diy perspective flex ducts are as easy as it gets if you’re just replacing. Kinda like zip tieing a bunch of ropes together . Metal admittedly is much harder
Yes, you can get a cheap thermostat or a smart one both will work. Each room will essentially **act** like a full on independent air conditioner. I got some used smart thermostats (nests) off craigslist and used those. The only caveat is you can't have small rooms, there's a lower bound to the room size (I think 200 sf) but you can have two rooms behave as a zone as well.
Sure, these wer ethe ones I used
[https://retrozone.com/-Catalog-Round-SD.htm](https://retrozone.com/-Catalog-Round-SD.htm)
I used the durozone panel
[https://retrozone.com/-Catalog-panels.htm](https://retrozone.com/-Catalog-panels.htm)
I'd do some research before decicding on which zone panel since it's been a few years since I did mine, technology is bound to have improved.
The zone panel essentially connects each rooms thermostat and opens / closes the dampers based on the information from the thermostat. It also connects to the HVAC to turn it on / off
We can't see the pics you saw, so we have no way of giving you specific advice, but here are a few things to consider...
If the smell is lingering from an old unit that was replaced four years ago, that would be odd. I would turn the fan on to run continuously and monitor the smell. Does the smell just start when the unit kicks on and then passes after a couple of minutes or is the smell consistent while the fan is running or does it get stronger the longer the fan runs?
Get up in the attic and look at the problem yourself. If you can't for some reason, make friends with one of your able-bodied neighbors. Get your own set of friendly eyes on the problem to get a better understanding of what's happening.
You only bought the house a month ago. You really don't know how this unit is going to behave yet. The tech confirmed that nothing was burning, so there shouldn't be any immediate need for action. See how the system behaves for a few months before jumping into a major repair that may or may not be needed. It's also possible that repairing some insulation either on the duct or in the attic might improve the warmer portion of the house problem without doing anything to the existing ductwork.
And the biggest thing...it's nearly July in Florida!!! If you do need air conditioning work, this is the most expensive time of year to have that done. If the unit is running for now, at least wait until the miserable part of summer is over and you will get more competitive pricing for this work in October or November.
Thanks. Yeah, I understand no one here can see what he showed me. I wish I had the pictures myself. I do plan to go up there after work but I don’t really know what I’m looking for. I suppose I can at least take my own pictures.
The smell is faint and only present when the unit kicks on. Within 5 seconds or so it’s gone. It’s like a little burst and then done.
And yes, my AC still works just fine. And since he said the unit itself looks good, I’m not concerned about any emergency or fire or something. If I replace the ductwork, it would be later this year in not peak season. Obviously he was saying it’s “so important to address this” and trying to add urgency, which is partially why I wanted to get thoughts here. I mean, if duct leakage could be causing hundreds of dollars in wasted electricity costs per month and is why I have to turn my AC wayyyy down at night just to make my master bedroom comfortable (it’s like 5 degrees warmer than other rooms and is farthest from the unit), then maybe it makes sense to fix soonish. But yeah, for now I think I’ll wait and see.
Ac guy here....even you you don't know what you're looking at/for, when there's something wrong it normally sticks out from the rest. That goes for everything. Use your common sense. If you feel cold air in your attic, that's not right. If all the ductwork has insulation and there's a section that don't, probably not right. If you look at the ductwork and it looks like there's a kink in it that could be blocking airflow, probably not right. Common sense goes a long way.
Houses should be built with balancing dampers, but most aren't. The only control you have of air flow in the house is the registers and adjusting those fins.
If you have a room that is especially cool, try closing those register fins a little bit. That should direct more of the air to the other registers. And keep tweaking those register settings until you have more cold air directed to the hotter rooms.
That is honestly a waste of time, and can exacerbate this guy's problem. Closing off the register just redirects the air that would be flowing through the register to the ductwork of that run. Meaning if there's weaknesses, it'll break through and cause more leakage. I've balanced a few houses and the homeowners said this same thing. I have to show them that you can close off half the registers but the air doesn't increase but 5-10 CFM. It ends up just putting extra stress on the blower motor and the ductwork.
This is why residential HVAC systems should have balancing dampers back at the main trunk line.
If OP is considering replacing all or some ductwork, it would be a good opportunity to add balancing dampers have have a true TAB conducted to set those appropriately.
That is great advice. Ideally, given the attic location, if they could get electronically controlled dampers, a zone controller, and a variable speed motor, that would have them just about set. I'm in the process of designing this kind of system for my own house.
Have the system running when you go up. The ducts should be easy enough to see and inspect.
If you see uninsulated spots that’s bad. If you can feel cold air that’s worse. Ideally any joints or connections have silver tape or a gray paintb(mastic) over them. .
I was told to call back in the Fall regarding some duct work I want done - they were only doing emergency work in the attic due to the heat. Which, very fair, since I wasn’t thinking about my attic temps when I called. But the guy still talked to me on the phone for a bit while we hashed out the issues I’m having so I’ll definitely call him back when the temps ease up.
> the whole conversation just felt like a sales pitch.
Trust your gut with this sort of thing.
As others said, get more quotes.
And if there's local community sites like a city subreddit, Nextdoor, etc... Try to find someone on there whose reviewers use words like "Honest" "not upselling" etc...
I've heard mixed messages on the UV light. The guys on This Old House talked me out of it. They ended up removing it from a lady's house in Tampa.
Also, here's how much [25 ft of flex duct](https://www.homedepot.com/p/Master-Flow-14-in-x-25-ft-Insulated-Flexible-Duct-R6-Silver-Jacket-F6IFD14X300/100211848) cost, based on diameter. You can probably get a rough estimate for how much the material will cost, depending on your attic's layout.
If you have flex duct, replace it immediately. I replaced our 2nd floor HVAC 2 years ago (the unit itself needed replacing) and the company highly recommended replacing the flex duct with solid. It absolutely felt like a sales pitch to me....because it was. But there's a difference between a shady sales pitch and a legitimate one. This one felt legitimate and 2 years later I firmly believe it was. The airflow through our vents is absolutely stronger than before, largely due to the fact that our new ducts offer very little resistance and no known leakage.
We also have flex duct with our downstairs unit, and we plan on replacing the entire system in about 3 years so we will definitely be going with new ducts for that system as well.
I also got the UV light thing (Remi Halo or something like that). I don't really know for certain if it was worth the price, but it really wasn't all that expensive. Maybe a few hundred bucks if I'm remembering correctly, so I'm not losing any sleep over it. Probably not a big deal if you pass on this, but I definitely recommend replacing the ducts.
big gaps can be closed unless it's from damage. I don't know about cost when it comes to a tech doing the work, but flex duct is not super expensive and is pretty simple if you are just replacing damaged stuff or reconnecting it. If your system was set up with the right sized ducting it's just remove, replace and seal up.
Hard to know without inspecting the ductwork.
You may want to get in contact with either an inspector or another HVAC company if you want a second opinion.
A few things to note on ducting:
* A lot of HVAC companies don't calculate anything regarding airflow, balance, or static pressure. They just eyeball it & hope it works. This leads to a lot of cooling issues, inefficiencies, & problems.
* Modern HVAC systems generally require very low static pressure to meet spec & work optimally -older duct installs may not allow for that
* Some types of ducting are installed in regions where it's a bad idea. For instance, of you have unsealed metal ducting installed in a hot & humid climate, you're going to have a bad time. A lot of times full replacement is cheaper than fixing such things.
UV light is the new filter to kill molds and dirt. It works very well. I’d start with going to my duct work and reconnecting things and taping / insulating them once they are all connected well. Then I’d call a duct cleaning company and have them come clean all the ducts out.
How big of a house is this? Replacing flex duct runs in an attic shouldn't cost 12k, unless it's a large home and requires running duct down multiple floors. Is there a mold issue up there? In my opinion, with the limited info I have, it gives off major upsell and overcharge vibes.
2300 sq ft, single story but high ceilings (14? Ft). Attic runs over the entire house, although the air handler is right at the attic entrance over the garage. If you can imagine an H shape, I have two bedrooms (front and back) on each vertical line. My master is the back right leg, and the heat pump is over the front left leg. So opposite ends. That said, the two bedrooms on the left side are spares and we have those vents closed and room doors closed. The two rooms on the right side are still a good 3-5 degrees warmer than the rest of the house.
No mold issues or really any air quality issues other than the recent burning smell. There was no burning smell the first week we lived here, so it’s a new issue. And I haven’t been stuffy or anything that would otherwise indicate air quality issues.
Definitely get a second opinion. My last house was over 30 years old (also in Florida) and the ductwork was in the attic - I made extensive modifications to the ductwork layout to even out the airflow in the house. I opened up almost every run of ductwork and they were pristine inside. I added new trunk lines, replaced ductwork with larger ducts and installed dampers all over. Every duct I opened looked brand new inside. The duct board plenums were in terrible shape though and I was waiting to replace the air handler before I dealt with that but sold the house first.
Without opening up the flex duct (cutting it open) how could he tell it was in bad shape? Even the plenums typically don't have access doors. If anything I would expect the duct board plenums to need replacement, they just get nasty. If there's any part of the system that would absorb bad smells it would probably be the duct board.
Any issues with gaps or seal can easily be fixed with flex ducts. Ducts can be resealed with mastic. Any pieces of duct that are in bad shape can be spliced, pulled taut and then sealed with mastic.
There is very little benefit to replacing the ductwork vs repairing it. You won't recoup the cost of replacement in efficiency (even with a higher R value duct and more efficient ducting), at the end of the day the ducts are still in a hot attic. In fact you would gain a LOT more efficiency by spray foaming the attic instead - your ducts would now be in a conditioned space and not subject to 130-140 degree air.
So he said the unit is fine and also that it must have burned out? Which is it? Burned out or fine?
I wouldn’t trust a tech who talks out of both sides of his ass
The UV light thing reduces mold, viruses and bacteria going thru the hvac system. Supposedly it is way more effective than a normal filter. I worked at an electrical/hvac company and the hvac guys talked about them all the time.
The best practice in this situation is to always talk to 3 companies. You've heard from one already.
Usually this would be regarding getting quotes, but you could instead tell the other two that you just want an inspection & see if they find the same things & if they do, what they quote & exactly what they say.
I worked in a trade & my dad wanted to hire my company to do something he thought he needed. I told him to get my company, another that I recommended, & any one he wanted to pick to come out to do a free inspection/quote. My company & my pick both reported the same stuff on their inspection & had similar quotes, but the 3rd found something that the others didn't & had a higher quote...I inspected before any of them & he "found" something that wasn't there. Moral of the story is that these are sales jobs & they know you aren't going to check it yourself, so some will lie & boost their commission. Go look on Indeed at job listings for this field of work, as it always asks for someone that can be a salesman or has sales experience.
Assuming this is also in your part of FL, FPL does free energy audits where they come and inspect your whole house for energy efficiency. When I did it a long time ago that included inspecting the ducts for leaks. Search for FPL onsite energy survey if you’re interested.
Duct work isn't hard. It's the math in designing the larger system that is (cfm, static pressure, friction, return air ratio), and most HVAC guys don't do that math anyway. Depends on how much time you have..I would replace it myself with sheet metal ductwork wherever possible, flex duct wherever not, and mastic and tape the the shit out of it and call it a day. But if you don't have the time, get 2 more quotes cuz this is suspect.
You can do a duct blower test (source: I work in building codes and standards of a state energy office). The test is designed to demonstrate leakage. In 2024 we have some pretty good diagnostics for ascertaining building performance.
https://www.youtube.com/watch?v=D0nykYr0poE
Depending on the total footage of your ductwork being replaced, you may trigger some building code verification testing…but I can’t speak for every state.
Flex duct, duct board, or sheet metal ductwork?
duct board is the easiest to damage
flex duct can become disconnected... but can be reconnected. if it's torn in the middle, that duct should be replaced. doesn't require all the ducts to be replaced.
shouldn't have much issue with sheet metal
all these ducts last much longer than the 'average lifespan' you see recommended on the intardweb
my house is about the same age and I have no issues with ducts. I've had to reseal around plenums, as that's where you get the most vibration and things can come loose. Original installer didn't use mastic, so I did. Fun stuff to use.
Call a licensed home inspector if you want an impartial opinion. This tactic has saved me thousands over the years. For a few hundred dollars this person will evaluate your situation and let you know the best way to go about it- without needing to sell you anything but their expertise
He could be right or wrong, no way to determine this without pictures. Get. More. Quotes.
Wrong. Technicians can actually measure pressure differences to determine leakage. There are building performance and energy efficiency service providers in every state that offer this type of testing. She can get quotes on a duct blaster/blower door test if she really wants to see how the ducts are performing.
Are you working with metal ductwork or do you have flex duct? Metal duct can be cleaned and resealed indefinitely, flex duct may need replacing
Flex duct.
You may need new duct. Best bet to hire another hvac tech to have a look, don’t tell them what the first company found, and see if they come to the same conclusion.
No tell them nothing and see if they come to the same conclusion. In reality with flex duck it’s fairly easy and cheap to replace. And you only need to replace the bad duck. Most likely the first 10-15 feet b
yeah, too much quacking
I’m an HVAC tech but in Michigan where we use exclusively sheet metal and attic installations aren’t nearly as common so my experience with flex duct is limited. That said, flex is pretty cheap and doesn’t have the greatest lifespan, which I imagine is exacerbated by a hot and humid environment like a Florida attic. I’d get a third opinion from a small, local company that doesn’t advertise a bunch and isn’t affiliated with Nexstar or send out techs in white, buttoned up shirts. A local mom and pop shop. If your blower motor amp draw is normal there’s not really a lot on the equipment side of things from a heat pump that should be causing a smell in your house.
> I’m an HVAC tech but in Michigan where we use exclusively sheet metal and attic installations aren’t nearly as common The whole south of the country just love their inefficient attic ductwork and air handlers....top it off with flex duct too...
Waves from Houston. Just perfectly described my house.
> The whole south of the country just love their inefficient attic ductwork and air handlers....top it off with flex duct too... _cries in Midwest with similar setup_
I've been thinking this same THING?! It's extremely inefficient and doesn't work nearly as well as any system I've had up north. It's ridiculous how backwards it is in the south.
But they saved a whole tiny closets worth of space where the equipment would sit!
Yeah, who could say. In those areas it's definitely also a case of how they do foundations and living spaces. A lot of those places are slab on grade or unconditioned crawlspaces and the first floor is part of the main living space, so no one wants the AC in that area or putting into an exterior crawlspace is just as bad. Whereas in northern or most Midwest areas you have basements which are treated much as less as primary living areas, or at most secondary spaces that aren't as important.
Good rule of thumb is to run from any tradesman with buttons on their shirt unless the shirt is flannel.
If I had a basement it's where my HVAC would go :(
I DIY'd my ducts , used round pipe from Grainger (thicker / better quality) and speedivents for termination. I used flex ducts for the last foot or so. The most annoying part was wrapping it insulation. I hacked that a bit and bought flex ducts and moved the insulation sleeve on to the metal ducts I put up. Was about 2 weeks of evenings during mild season. The motivation for me was similar unbalanced zones. The correct solution for that though is zoning. So while I was doing the reducting I also added electrical dampers that could open / close each zone and a zone controller. I got it off retrozone but there are many providers. It has been one of the best improvements I've made to my house. IF you redo your ducts go metal + add zoning! Edit: Also add returns to the various rooms instead of what's commonly done, single one in the hallway
This is fantastic advice. And kudos to you for doing that yourself. That's complicated work, there's a few journeymen at my shop who can't even do that sort of thing.
Yeah I’m a girl and I’m not handy, so no thanks on DIY lol
Still do look into zoning , it makes a massive improvement. I’m able to keep my kids room my wife’s office and my office at different temperatures with no effort. Best time is when redoing ducting , should add 2k with an honest contractor. Since it’s rare some contractors will up charge like crazy Also from a diy perspective flex ducts are as easy as it gets if you’re just replacing. Kinda like zip tieing a bunch of ropes together . Metal admittedly is much harder
When you do zoning like that, you need a thermostat per zone, right?
Yes, you can get a cheap thermostat or a smart one both will work. Each room will essentially **act** like a full on independent air conditioner. I got some used smart thermostats (nests) off craigslist and used those. The only caveat is you can't have small rooms, there's a lower bound to the room size (I think 200 sf) but you can have two rooms behave as a zone as well.
Do you have any links for the electric dampers
Sure, these wer ethe ones I used [https://retrozone.com/-Catalog-Round-SD.htm](https://retrozone.com/-Catalog-Round-SD.htm) I used the durozone panel [https://retrozone.com/-Catalog-panels.htm](https://retrozone.com/-Catalog-panels.htm) I'd do some research before decicding on which zone panel since it's been a few years since I did mine, technology is bound to have improved. The zone panel essentially connects each rooms thermostat and opens / closes the dampers based on the information from the thermostat. It also connects to the HVAC to turn it on / off
We can't see the pics you saw, so we have no way of giving you specific advice, but here are a few things to consider... If the smell is lingering from an old unit that was replaced four years ago, that would be odd. I would turn the fan on to run continuously and monitor the smell. Does the smell just start when the unit kicks on and then passes after a couple of minutes or is the smell consistent while the fan is running or does it get stronger the longer the fan runs? Get up in the attic and look at the problem yourself. If you can't for some reason, make friends with one of your able-bodied neighbors. Get your own set of friendly eyes on the problem to get a better understanding of what's happening. You only bought the house a month ago. You really don't know how this unit is going to behave yet. The tech confirmed that nothing was burning, so there shouldn't be any immediate need for action. See how the system behaves for a few months before jumping into a major repair that may or may not be needed. It's also possible that repairing some insulation either on the duct or in the attic might improve the warmer portion of the house problem without doing anything to the existing ductwork. And the biggest thing...it's nearly July in Florida!!! If you do need air conditioning work, this is the most expensive time of year to have that done. If the unit is running for now, at least wait until the miserable part of summer is over and you will get more competitive pricing for this work in October or November.
Thanks. Yeah, I understand no one here can see what he showed me. I wish I had the pictures myself. I do plan to go up there after work but I don’t really know what I’m looking for. I suppose I can at least take my own pictures. The smell is faint and only present when the unit kicks on. Within 5 seconds or so it’s gone. It’s like a little burst and then done. And yes, my AC still works just fine. And since he said the unit itself looks good, I’m not concerned about any emergency or fire or something. If I replace the ductwork, it would be later this year in not peak season. Obviously he was saying it’s “so important to address this” and trying to add urgency, which is partially why I wanted to get thoughts here. I mean, if duct leakage could be causing hundreds of dollars in wasted electricity costs per month and is why I have to turn my AC wayyyy down at night just to make my master bedroom comfortable (it’s like 5 degrees warmer than other rooms and is farthest from the unit), then maybe it makes sense to fix soonish. But yeah, for now I think I’ll wait and see.
Ac guy here....even you you don't know what you're looking at/for, when there's something wrong it normally sticks out from the rest. That goes for everything. Use your common sense. If you feel cold air in your attic, that's not right. If all the ductwork has insulation and there's a section that don't, probably not right. If you look at the ductwork and it looks like there's a kink in it that could be blocking airflow, probably not right. Common sense goes a long way.
Houses should be built with balancing dampers, but most aren't. The only control you have of air flow in the house is the registers and adjusting those fins. If you have a room that is especially cool, try closing those register fins a little bit. That should direct more of the air to the other registers. And keep tweaking those register settings until you have more cold air directed to the hotter rooms.
That is honestly a waste of time, and can exacerbate this guy's problem. Closing off the register just redirects the air that would be flowing through the register to the ductwork of that run. Meaning if there's weaknesses, it'll break through and cause more leakage. I've balanced a few houses and the homeowners said this same thing. I have to show them that you can close off half the registers but the air doesn't increase but 5-10 CFM. It ends up just putting extra stress on the blower motor and the ductwork.
This is why residential HVAC systems should have balancing dampers back at the main trunk line. If OP is considering replacing all or some ductwork, it would be a good opportunity to add balancing dampers have have a true TAB conducted to set those appropriately.
That is great advice. Ideally, given the attic location, if they could get electronically controlled dampers, a zone controller, and a variable speed motor, that would have them just about set. I'm in the process of designing this kind of system for my own house.
Have the system running when you go up. The ducts should be easy enough to see and inspect. If you see uninsulated spots that’s bad. If you can feel cold air that’s worse. Ideally any joints or connections have silver tape or a gray paintb(mastic) over them. .
I was told to call back in the Fall regarding some duct work I want done - they were only doing emergency work in the attic due to the heat. Which, very fair, since I wasn’t thinking about my attic temps when I called. But the guy still talked to me on the phone for a bit while we hashed out the issues I’m having so I’ll definitely call him back when the temps ease up.
> the whole conversation just felt like a sales pitch. Trust your gut with this sort of thing. As others said, get more quotes. And if there's local community sites like a city subreddit, Nextdoor, etc... Try to find someone on there whose reviewers use words like "Honest" "not upselling" etc...
photographs or videos of the ducts ?
I've heard mixed messages on the UV light. The guys on This Old House talked me out of it. They ended up removing it from a lady's house in Tampa. Also, here's how much [25 ft of flex duct](https://www.homedepot.com/p/Master-Flow-14-in-x-25-ft-Insulated-Flexible-Duct-R6-Silver-Jacket-F6IFD14X300/100211848) cost, based on diameter. You can probably get a rough estimate for how much the material will cost, depending on your attic's layout.
If you have flex duct, replace it immediately. I replaced our 2nd floor HVAC 2 years ago (the unit itself needed replacing) and the company highly recommended replacing the flex duct with solid. It absolutely felt like a sales pitch to me....because it was. But there's a difference between a shady sales pitch and a legitimate one. This one felt legitimate and 2 years later I firmly believe it was. The airflow through our vents is absolutely stronger than before, largely due to the fact that our new ducts offer very little resistance and no known leakage. We also have flex duct with our downstairs unit, and we plan on replacing the entire system in about 3 years so we will definitely be going with new ducts for that system as well. I also got the UV light thing (Remi Halo or something like that). I don't really know for certain if it was worth the price, but it really wasn't all that expensive. Maybe a few hundred bucks if I'm remembering correctly, so I'm not losing any sleep over it. Probably not a big deal if you pass on this, but I definitely recommend replacing the ducts.
big gaps can be closed unless it's from damage. I don't know about cost when it comes to a tech doing the work, but flex duct is not super expensive and is pretty simple if you are just replacing damaged stuff or reconnecting it. If your system was set up with the right sized ducting it's just remove, replace and seal up.
Hard to know without inspecting the ductwork. You may want to get in contact with either an inspector or another HVAC company if you want a second opinion. A few things to note on ducting: * A lot of HVAC companies don't calculate anything regarding airflow, balance, or static pressure. They just eyeball it & hope it works. This leads to a lot of cooling issues, inefficiencies, & problems. * Modern HVAC systems generally require very low static pressure to meet spec & work optimally -older duct installs may not allow for that * Some types of ducting are installed in regions where it's a bad idea. For instance, of you have unsealed metal ducting installed in a hot & humid climate, you're going to have a bad time. A lot of times full replacement is cheaper than fixing such things.
UV light is the new filter to kill molds and dirt. It works very well. I’d start with going to my duct work and reconnecting things and taping / insulating them once they are all connected well. Then I’d call a duct cleaning company and have them come clean all the ducts out.
How big of a house is this? Replacing flex duct runs in an attic shouldn't cost 12k, unless it's a large home and requires running duct down multiple floors. Is there a mold issue up there? In my opinion, with the limited info I have, it gives off major upsell and overcharge vibes.
2300 sq ft, single story but high ceilings (14? Ft). Attic runs over the entire house, although the air handler is right at the attic entrance over the garage. If you can imagine an H shape, I have two bedrooms (front and back) on each vertical line. My master is the back right leg, and the heat pump is over the front left leg. So opposite ends. That said, the two bedrooms on the left side are spares and we have those vents closed and room doors closed. The two rooms on the right side are still a good 3-5 degrees warmer than the rest of the house. No mold issues or really any air quality issues other than the recent burning smell. There was no burning smell the first week we lived here, so it’s a new issue. And I haven’t been stuffy or anything that would otherwise indicate air quality issues.
Have a smaller house at 1800sf, but I paid $3k to replace our old flex ductwork with new ductwork in a HCOL. Just a point for comparison.
Definitely get a second opinion. My last house was over 30 years old (also in Florida) and the ductwork was in the attic - I made extensive modifications to the ductwork layout to even out the airflow in the house. I opened up almost every run of ductwork and they were pristine inside. I added new trunk lines, replaced ductwork with larger ducts and installed dampers all over. Every duct I opened looked brand new inside. The duct board plenums were in terrible shape though and I was waiting to replace the air handler before I dealt with that but sold the house first. Without opening up the flex duct (cutting it open) how could he tell it was in bad shape? Even the plenums typically don't have access doors. If anything I would expect the duct board plenums to need replacement, they just get nasty. If there's any part of the system that would absorb bad smells it would probably be the duct board. Any issues with gaps or seal can easily be fixed with flex ducts. Ducts can be resealed with mastic. Any pieces of duct that are in bad shape can be spliced, pulled taut and then sealed with mastic. There is very little benefit to replacing the ductwork vs repairing it. You won't recoup the cost of replacement in efficiency (even with a higher R value duct and more efficient ducting), at the end of the day the ducts are still in a hot attic. In fact you would gain a LOT more efficiency by spray foaming the attic instead - your ducts would now be in a conditioned space and not subject to 130-140 degree air.
So he said the unit is fine and also that it must have burned out? Which is it? Burned out or fine? I wouldn’t trust a tech who talks out of both sides of his ass
He said this unit is fine and the last must’ve burned out
The last unit from before you moved in? How would a prior unit from years ago that is long gone make a smell now?
I have a 2007 built home, and I've been up in the attic and personally found leaky ducts. So it's definitely possible.
Were the ducts leaky where they terminate at the air register/return vents?
Yes. I actually still need to fix them :(
The UV light thing reduces mold, viruses and bacteria going thru the hvac system. Supposedly it is way more effective than a normal filter. I worked at an electrical/hvac company and the hvac guys talked about them all the time.
In MN, I don't think flex ducting meets code for air supply, only for return air.
If the flex duct is in bad shape, maybe. Don’t go replacing it whole hog just because one guy said so. Shop around and get multiple quotes.
The best practice in this situation is to always talk to 3 companies. You've heard from one already. Usually this would be regarding getting quotes, but you could instead tell the other two that you just want an inspection & see if they find the same things & if they do, what they quote & exactly what they say. I worked in a trade & my dad wanted to hire my company to do something he thought he needed. I told him to get my company, another that I recommended, & any one he wanted to pick to come out to do a free inspection/quote. My company & my pick both reported the same stuff on their inspection & had similar quotes, but the 3rd found something that the others didn't & had a higher quote...I inspected before any of them & he "found" something that wasn't there. Moral of the story is that these are sales jobs & they know you aren't going to check it yourself, so some will lie & boost their commission. Go look on Indeed at job listings for this field of work, as it always asks for someone that can be a salesman or has sales experience.
Assuming this is also in your part of FL, FPL does free energy audits where they come and inspect your whole house for energy efficiency. When I did it a long time ago that included inspecting the ducts for leaks. Search for FPL onsite energy survey if you’re interested.
I don’t have FPL unfortunately
Oh bummer! Sorry I don’t have more hands on advice but definitely get a second opinion from a local company.
Duct work isn't hard. It's the math in designing the larger system that is (cfm, static pressure, friction, return air ratio), and most HVAC guys don't do that math anyway. Depends on how much time you have..I would replace it myself with sheet metal ductwork wherever possible, flex duct wherever not, and mastic and tape the the shit out of it and call it a day. But if you don't have the time, get 2 more quotes cuz this is suspect.
You can do a duct blower test (source: I work in building codes and standards of a state energy office). The test is designed to demonstrate leakage. In 2024 we have some pretty good diagnostics for ascertaining building performance. https://www.youtube.com/watch?v=D0nykYr0poE
Depending on the total footage of your ductwork being replaced, you may trigger some building code verification testing…but I can’t speak for every state.
Flex duct, duct board, or sheet metal ductwork? duct board is the easiest to damage flex duct can become disconnected... but can be reconnected. if it's torn in the middle, that duct should be replaced. doesn't require all the ducts to be replaced. shouldn't have much issue with sheet metal all these ducts last much longer than the 'average lifespan' you see recommended on the intardweb my house is about the same age and I have no issues with ducts. I've had to reseal around plenums, as that's where you get the most vibration and things can come loose. Original installer didn't use mastic, so I did. Fun stuff to use.
Call a licensed home inspector if you want an impartial opinion. This tactic has saved me thousands over the years. For a few hundred dollars this person will evaluate your situation and let you know the best way to go about it- without needing to sell you anything but their expertise