What's up guys, long time lurker first time poster. Long post but two questions.
1. Can I remove this odd 2x6 in my return plenum and replace it with metal flat bar? - I can't figure out what this would be supporting, the air handler above seems like a 2x6 would be overkill and that I can add a thin metal bar in between and clear up the area for better airflow.
2. X-posted to HVAC forum but there's plenty of overlap here so I figured why not: Can contractor cut subfloor and add flex to a return to increase return air volume to lower high static pressure.
"Good Morning and Happy Labor Day,
Home is Central Texas 1950's 1,600ft single story ranch on pier and beam (shallow crawl space, about 24 inches tall max) - AC added as a retrofit 50 years ago. Indoor air handler/furnace in HVAC closet next to water heater. Previous owner was older woman. She had a 3 ton Goodman furnace/ac installed in early 2010. Coil/condenser/blower all function well, great condition, noisy at the return though.
Air handler is an upflow in a utility closet in center of the house with return plenum underneath, return on each wall at base. 80% Furnace with combustion coming into closet from attic. Metal pipe ductwork from handler into attic with well-insulated jackets in great condition. Air sealed attic floor and R38 blown fiberglass above. Company that installed the AC system in 2010 installed two 32x14 return grilles on each side of the closet walls "to create a larger return area" (she/previous owner was told).
However, under the return grilles the actual opening is 24x12 (on each side of the wall). Taking the grilles off you can see they just covered a large portion of wall with no return area behind it. It's disappointing and it appears the installers took some liberty with "sizing" the returns. Further, there is framing that was never removed inside the plenum and partially in the way. So actual measurement it's more like 21x12 of intake area. It's pretty turbulent in the plenum. One grille in living room and one in hallway. Supply throughout is good though there is an imbalance in the kitchen/dining room furthest from the return and the sound could be better. It's about 60db in living room near return when unit kicks on.
At 21 x 12 for each return that puts me at 504 square inches of return area while I need at least 600. I'm stumped on how to get more. I've had several HVAC companies out - including who I believe installed the system (they say it wasn't them - previous owner's daughter said it was, old woman has since passed). Fast forward to now - I bought the house. I'm not mad about it - just trying to remedy it.
My buddy does commercial HVAC one state over - he dropped by a couple weeks ago and confirmed my return was lacking. He suggested posting here for the centuries of combined knowledge. I'm a longtime lurker, first time poster, can't add pics yet and am somewhat against posting just to post as I usually can't add much of value here. Of the 5 people that came out:
First company said I can "get away with" about 150 square inches of return per ton and that my blower was just loud because it's behind the wall and static pressure is slightly higher. I have a 20x25x2 pleated MERV 7 at the unit. He said just enlarge the returns by raising the plenum height of the closet when I replace the system, reasoning that lifting the unit now would not be economical, and that my blower isn't starved enough to cause damage. He said the fact it's 15 years old shows that. He said that the cost to fix the noisy return would likely be extravagant. He some systems were just louder than others.
Second company basically said you definitely need a whole new system but when asked why he told me "it's just old." He said he was a former tech but is now on the sales side because of his install knowledge. Gave insane quotes, then said he would cut one in half if I did cash. He said he measured by eye. I wasn't a huge fan but I'm not knocking him. He put gauges on nothing and didn't take static.
Had another one out like him - he seemed busy and told me to get a variable blower system. I wasn't a fan.
Third company, I felt was very honest. He said it's possible to cut the bottom of the plenum and run insulated flex under the floor through the crawl space to add a return about 15 feet away. Told me that would make up what I'm lacking in return and that by running 10x12 of supported and insulated flex through the crawl space would be the most economical. He said retrofits require creativity and this was one of them. It made sense to me. I liked that idea and his quote was reasonable. However, I can't say I've heard of this.
The third company's plan: cut subfloor under return plenum and add a 15 foot run of 10x12 insulated flex to the underside of a cabinet in the dining room and put a 20x20 grille in the wall. Two 90 degree elbows. He said it should provide adequate return/help balance temps and reduce intake sound. The price he gave was reasonable.
My tech buddy said it's possible but uncommon, he said the concern would be making sure there are no leaks as the crawlspace would then become the part of the return. He also mentioned that because this would draw from the bottom of the plenum and with the existing return openings on the sides of the existing plenum I may not get the sound down as much as I want because of turbulence (I've seen Psychrometrics discussed here briefly and after some light googling of it, it simply makes me admire the trade more). He ultimately thought this was the best idea but again said drop it in here and see what the collective knowledge says.
If installed tight/no leaks, supported and insulated, are there any downsides cutting bottom of plenum to run through crawl space?
(Crawlspace is sealed, has newer 12mil and a 120p dehumidifier)
If needed:
Goodman GSX130421BA Condenser
Goodman CAPF3642C6DB Coil"
1. Can I remove this odd 2x6 in my return plenum and replace it with metal flat bar? - I can't figure out what this would be supporting, the air handler above seems like a 2x6 would be overkill and that I can add a thin metal bar in between and clear up the area for better airflow.
2. X-posted to HVAC forum but there's plenty of overlap here so I figured why not: Can contractor cut subfloor and add flex to a return to increase return air volume to lower high static pressure.
"Good Morning and Happy Labor Day,
Home is Central Texas 1950's 1,600ft single story ranch on pier and beam (shallow crawl space, about 24 inches tall max) - AC added as a retrofit 50 years ago. Indoor air handler/furnace in HVAC closet next to water heater. Previous owner was older woman. She had a 3 ton Goodman furnace/ac installed in early 2010. Coil/condenser/blower all function well, great condition, noisy at the return though.
Air handler is an upflow in a utility closet in center of the house with return plenum underneath, return on each wall at base. 80% Furnace with combustion coming into closet from attic. Metal pipe ductwork from handler into attic with well-insulated jackets in great condition. Air sealed attic floor and R38 blown fiberglass above. Company that installed the AC system in 2010 installed two 32x14 return grilles on each side of the closet walls "to create a larger return area" (she/previous owner was told).
However, under the return grilles the actual opening is 24x12 (on each side of the wall). Taking the grilles off you can see they just covered a large portion of wall with no return area behind it. It's disappointing and it appears the installers took some liberty with "sizing" the returns. Further, there is framing that was never removed inside the plenum and partially in the way. So actual measurement it's more like 21x12 of intake area. It's pretty turbulent in the plenum. One grille in living room and one in hallway. Supply throughout is good though there is an imbalance in the kitchen/dining room furthest from the return and the sound could be better. It's about 60db in living room near return when unit kicks on.
At 21 x 12 for each return that puts me at 504 square inches of return area while I need at least 600. I'm stumped on how to get more. I've had several HVAC companies out - including who I believe installed the system (they say it wasn't them - previous owner's daughter said it was, old woman has since passed). Fast forward to now - I bought the house. I'm not mad about it - just trying to remedy it.
My buddy does commercial HVAC one state over - he dropped by a couple weeks ago and confirmed my return was lacking. He suggested posting here for the centuries of combined knowledge. I'm a longtime lurker, first time poster, can't add pics yet and am somewhat against posting just to post as I usually can't add much of value here. Of the 5 people that came out:
First company said I can "get away with" about 150 square inches of return per ton and that my blower was just loud because it's behind the wall and static pressure is slightly higher. I have a 20x25x2 pleated MERV 7 at the unit. He said just enlarge the returns by raising the plenum height of the closet when I replace the system, reasoning that lifting the unit now would not be economical, and that my blower isn't starved enough to cause damage. He said the fact it's 15 years old shows that. He said that the cost to fix the noisy return would likely be extravagant. He some systems were just louder than others.
Second company basically said you definitely need a whole new system but when asked why he told me "it's just old." He said he was a former tech but is now on the sales side because of his install knowledge. Gave insane quotes, then said he would cut one in half if I did cash. He said he measured by eye. I wasn't a huge fan but I'm not knocking him. He put gauges on nothing and didn't take static.
Had another one out like him - he seemed busy and told me to get a variable blower system. I wasn't a fan.
Third company, I felt was very honest. He said it's possible to cut the bottom of the plenum and run insulated flex under the floor through the crawl space to add a return about 15 feet away. Told me that would make up what I'm lacking in return and that by running 10x12 of supported and insulated flex through the crawl space would be the most economical. He said retrofits require creativity and this was one of them. It made sense to me. I liked that idea and his quote was reasonable. However, I can't say I've heard of this.
The third company's plan: cut subfloor under return plenum and add a 15 foot run of 10x12 insulated flex to the underside of a cabinet in the dining room and put a 20x20 grille in the wall. Two 90 degree elbows. He said it should provide adequate return/help balance temps and reduce intake sound. The price he gave was reasonable.
My tech buddy said it's possible but uncommon, he said the concern would be making sure there are no leaks as the crawlspace would then become the part of the return. He also mentioned that because this would draw from the bottom of the plenum and with the existing return openings on the sides of the existing plenum I may not get the sound down as much as I want because of turbulence (I've seen Psychrometrics discussed here briefly and after some light googling of it, it simply makes me admire the trade more). He ultimately thought this was the best idea but again said drop it in here and see what the collective knowledge says.
If installed tight/no leaks, supported and insulated, are there any downsides cutting bottom of plenum to run through crawl space?
(Crawlspace is sealed, has newer 12mil and a 120p dehumidifier)
If needed:
Goodman GSX130421BA Condenser
Goodman CAPF3642C6DB Coil"