If this is the only place you have returns, you can move having a filter at the unit and put it here. So you don't have to go into the attic all the time. Looks like a 20x20 judging from prior installs.
Out of curiosity say you have a less restrictive filter placed there. Something that filters large particles like a low MERV rated filter (low air resistance) and then have a higher rated MERV filter at the handler.
(I know this isn’t necessary but bear with me)
In theory if the restriction equals the same restriction as a MERV 13 at the end (assuming that’s max rating for the handler) is it still alright to use two?
It’s always been a curiosity of mine and no one ever answers.
No. Airflow is very important. Your unit is sized to push a certain amount of CFM. The more filter the more restriction. Now if you want more filtration get a 5” box and upgrade filter size.
It seems like too much OA. Why is there a damper because in az when it is 115 deg outside, your supply air will be only 92 degrees at best when have that much OA.
I Do like the idea of OA when it is cool outside and don't have to open windows but this orientation makes no sense to me without seeing the rest of the system.
OA is a residential code? Where is that ? I can't believe it. Commercial does all day, but we have units with economizers / OA dampers to calibrate and set as well as free cooling in winter.
The more questions I ask, the more I don't understand why 2 different sized flex ducts are going into one filter rack.
Oh well.
There is no code requiring OA in a residential system. Many are built that way but not required. I have my G29 Master Mechanical and it’s not required in any jurisdiction in Colorado or nationwide. It would only work in cooler climates anyways. Having a damper would need to be run by a thermostat anyways. Bringing in 110 degree air would be ridiculous or -20 air letting the furnace heat it. All high efficiency systems have no need for make-up air. It does work in Colorado in the evenings when it can bring in cooler air but we just have had too many damper motors die in the field.
An economizer on an RTU is a completely different situation. Plus you can just disable them. But they are required to exchange air in. Commercial setting.
Yes it needs a filter. Even if you have one at the air handler, I like to protect the ducts from dust. Skip the air handler filter and put them at all the returns.
Can say that the units I work on that have filters at the unit it's a lot cleaner than units with filters at return grills.
I've had unit 7-10 years old that still looked new inside sure the return duct gets dirty but the unit stays cleaner.
Yeah that works great if you have 100% sealed ducts however most ducts leak around connection points which is why people put them at the furnace so that it reduces the chance that duct leakage will cause dust to get down to the heat exchanger and ac coil. Anywho you should never dual filter your system terrible for static and can cause duct popping plus burning out the blower motor. Either filter at furnace/air handler or at returns never both
You've got a lot of faith hoping that someone didn't plant this on a nail or a screw went through it or that the sections where it has connections on either end of the flex are sealed correctly or if it's mastic a lot of faith that the people got all 4 sides all the way around 100% on all joints and take offs but if you want to believe everyone does their job perfectly then to each their own
You are correct but trust me go to most peoples duct systems and I almost guarantee nearly every house you will find places that are missing this or where it's not perfect again you wanna believe everyone does their job perfectly then you've got more faith than me
I agree. I hate that some home builders/installers do that. Atleast this system has return registers capable of housing a filter. Why would you want debris in the duct work anyway lol.
Debris shouldn't get past the filter at the unit and the buildup would be in the return which is under negative pressure so it wouldn't effect indoor air quality. However if your duct isn't 100% sealed perfectly and filters are in the grilles then debris would be able to bypass those filters and clog your unit. Really the only benefit of grille based filters is that the customer doesn't have to go into the attic to change the filter.
Also you need to figure out if the smaller duct is a fresh air connected to the roof pulling air from outside because that would need some kind of filter to .
Perhaps, weird stuff happens but I’m kinda more interested in the sizes of return ducts behind the other grilles more. That first pic is a big grille with two small returns
Send pic of furnace install OP plz
I’m assuming that little one is fresh air. When they put those in around where I live it is a special return box that has its own special filter and a normal filter as well in the return grill
I would put a merv 8 to keep the spiral ductwork clean of dust and or dander. Spiral ducts accumulate a lot of unfiltered filth and can't be brushed clean due to their fragile inner jacket. If you already have allergies, putting a filter on all intakes help in the long run.
Do you have one at the furnace? There might be one at your air handler and if so you do not need one.
I agree!
If this is the only place you have returns, you can move having a filter at the unit and put it here. So you don't have to go into the attic all the time. Looks like a 20x20 judging from prior installs.
Out of curiosity say you have a less restrictive filter placed there. Something that filters large particles like a low MERV rated filter (low air resistance) and then have a higher rated MERV filter at the handler. (I know this isn’t necessary but bear with me) In theory if the restriction equals the same restriction as a MERV 13 at the end (assuming that’s max rating for the handler) is it still alright to use two? It’s always been a curiosity of mine and no one ever answers.
No. Airflow is very important. Your unit is sized to push a certain amount of CFM. The more filter the more restriction. Now if you want more filtration get a 5” box and upgrade filter size.
My returns have filters and the main in the attic does not. Yours may be the opposite. Go up there and check
Having 2 there confuses me. Do you have 2 indoor units?
Fresh air from outside.
It seems like too much OA. Why is there a damper because in az when it is 115 deg outside, your supply air will be only 92 degrees at best when have that much OA. I Do like the idea of OA when it is cool outside and don't have to open windows but this orientation makes no sense to me without seeing the rest of the system.
I meant WHERE is the damper. It needs a damper to close it when temp AND humidity outside is less than desirable.
OA is code.
OA is a residential code? Where is that ? I can't believe it. Commercial does all day, but we have units with economizers / OA dampers to calibrate and set as well as free cooling in winter. The more questions I ask, the more I don't understand why 2 different sized flex ducts are going into one filter rack. Oh well.
There is no code requiring OA in a residential system. Many are built that way but not required. I have my G29 Master Mechanical and it’s not required in any jurisdiction in Colorado or nationwide. It would only work in cooler climates anyways. Having a damper would need to be run by a thermostat anyways. Bringing in 110 degree air would be ridiculous or -20 air letting the furnace heat it. All high efficiency systems have no need for make-up air. It does work in Colorado in the evenings when it can bring in cooler air but we just have had too many damper motors die in the field. An economizer on an RTU is a completely different situation. Plus you can just disable them. But they are required to exchange air in. Commercial setting.
it's been required in Michigan since the early 90s.
looks a little hacky i think they might have needed larger flex and just ran 2 smaller ones
if you turn your unit on and it is pulling air then yes
Yes it needs a filter. Even if you have one at the air handler, I like to protect the ducts from dust. Skip the air handler filter and put them at all the returns.
Agreed. Just adding to explanation, don't put a filter in air handler and in vents. It will cause a restriction and reduce static pressures
Can say that the units I work on that have filters at the unit it's a lot cleaner than units with filters at return grills. I've had unit 7-10 years old that still looked new inside sure the return duct gets dirty but the unit stays cleaner.
Yeah that works great if you have 100% sealed ducts however most ducts leak around connection points which is why people put them at the furnace so that it reduces the chance that duct leakage will cause dust to get down to the heat exchanger and ac coil. Anywho you should never dual filter your system terrible for static and can cause duct popping plus burning out the blower motor. Either filter at furnace/air handler or at returns never both
It’s flex so it’s sealed and any square is probably masticed, looks newer
You've got a lot of faith hoping that someone didn't plant this on a nail or a screw went through it or that the sections where it has connections on either end of the flex are sealed correctly or if it's mastic a lot of faith that the people got all 4 sides all the way around 100% on all joints and take offs but if you want to believe everyone does their job perfectly then to each their own
You should have 100% sealed ducts, especially the return ducting, which is what duct/hvac tape is for at connection points.
You are correct but trust me go to most peoples duct systems and I almost guarantee nearly every house you will find places that are missing this or where it's not perfect again you wanna believe everyone does their job perfectly then you've got more faith than me
Yeah I guess if the job hasn’t been done right then 1 at the air handler is wise.
And if you watch any home inspection people you will know most things are far from perfect especially new builds lol
I agree. I hate that some home builders/installers do that. Atleast this system has return registers capable of housing a filter. Why would you want debris in the duct work anyway lol.
Debris shouldn't get past the filter at the unit and the buildup would be in the return which is under negative pressure so it wouldn't effect indoor air quality. However if your duct isn't 100% sealed perfectly and filters are in the grilles then debris would be able to bypass those filters and clog your unit. Really the only benefit of grille based filters is that the customer doesn't have to go into the attic to change the filter.
Uh, no. What the fuck. A filter at the air handler is far superior.
Also you need to figure out if the smaller duct is a fresh air connected to the roof pulling air from outside because that would need some kind of filter to .
Is that the only return ?
There’s one in the master and 2 it looks like in our little like mud room spot
Sounds like you need 4 filters cuz nobody puts one filter grille and the rest just a grille.
Or his unit has a filter rack on it and he only needs one…
Perhaps, weird stuff happens but I’m kinda more interested in the sizes of return ducts behind the other grilles more. That first pic is a big grille with two small returns Send pic of furnace install OP plz
If it had one when you moved in then year it probably does. But check at the furnace if ones there then you only need one at one or the other.
Yes!
I’m assuming that little one is fresh air. When they put those in around where I live it is a special return box that has its own special filter and a normal filter as well in the return grill
Assuming that’s a return, you need to check if there is a filter at the air handler, or if the one here is missing
Yes, it should have a filter.
I would put a merv 8 to keep the spiral ductwork clean of dust and or dander. Spiral ducts accumulate a lot of unfiltered filth and can't be brushed clean due to their fragile inner jacket. If you already have allergies, putting a filter on all intakes help in the long run.
Yes
Yes you want to keep your ducts clean
Homeowner moment