The house was built in 1955 as a typical cookie cutter 3/2 1250sgft “L” shape. Furnace only (socal area) 6-6” stiff/alum vents, 1 in each bedroom, 1 kitchen, 1 dining, 1 family room.
A 500sqft Bonus Room was added (house is now shaped like a “U”) and they tap the plenum to attach a 12” insulated flex line and run it 40’, then split it into 2 lines a 20’ and 5’, along with a 4ton Rheem Classic X. Now 30yrs. later its’ given up the ghost. The bonus room was never cool enough in the summer nor warm enough in the winter. The airflow was a trickle compared to the bedrooms.
Most recent ACtech said the whole plenum needs to be changed out because he noted a tapered transition from the evap coil to the plenum. Stating the 4ton wants to put out 1600cuft and the plenum is only designed for 1200cuft (the original 6 – 6” ducts. That makes sense and not questioning it, but this is where the story gets interesting.
I have already changed out all the windows (3 -1ea E, S, W- 5’x4’ and 2ea both S-18’x4’ to vinyl double pane a few years ago. And now want to change all the ducting to insulated and reflective R8, Air-Seal the 13 recessed lights and the rest of the attic, blow in or batt in R38 insulation and put in baffles and 1 AC powered (set to 110) thermostatic gable fan and radiant barrier foil. I also cut in a few yrs. ago about 500sq.in of soffit into the bonus room as it had none, but did have 1300sq.in. of dormer and gable vents. I think I need another 600sq.in. of soffit though.
I’m thinking the house could keep the plenum and work with a 3Ton 14 SEER single stage R22 or 16 SEER 2 stage 410 system. Problem is every contractor says 4 ton and won’t do load calcs. They just say they know. On top of that they only want to do the change out and not the ducts. I say I’m losing a significant amount via the metal ducting seems and they say it is not as much as the marketing people would like me to think. I read both sides about how it doesn’t actually blow out the seams but via the venturi effect sucks in dust and asbestos. I think it blows out the seams but willing to admit probably not as much as I was once thinking.
Should I keep looking for someone that will do a manual J or at least something similar? I have found a few free online calc but they are pretty rough, but do back up my cognitive bias that the answer is leaning in my direction more than away.
On top of it all they are all coming in around 14k-16 for 4Ton American Standard 16SEER 2 stage systems, with 1 outsider at 8,5k.
Lastly I heard and believe the saying, the most important day of a units life is the first day (commissioning). I understand this to be the technician taking his time, a fair amount of waiting, waiting for refrigerant to normalize, putting it in slowly/properly, wet rags where needed, torch technique (Schrader valve), basically proper procedures and that a fair amount of guys rush it which always hurts the homeowner and benefits them in the form of repeat business.
I’m trying to figure out how to protect myself from this. I don’t get to pick the tech that comes out to do the install with these big companies. And if you go with the small guy he likely hasn’t done as many jobs. But if he’s older, than he has done plenty jobs but could be retiring soon. So it seems the only safe way to play it, is pay for the “maintenance” package of $150yr for 10yrs. which additionally protects you because all these 10yr. parts and LABOR warranties are only good if you buy the maintenance package. I don’t like the idea of a tech hooking up gauges every year just to say it is fine. If he did his job and there are no factory defects and airflow is balance correctly, it should stay a closed system until it proves itself otherwise.
How long does it take to properly initially setup a system once it is installed? 3hrs? Is there a website, maybe a tech school pdf that might have the proper sequence of events. I got into this discussion with only one sales guy/comfort advisor and he said his company requires the techs to take pictures throughout the install so each step is time stamped. I don’t know if this is good or bad. I guess it is cya for the company in case of factor defects and hopefully less free truck rolls if the tech built a solid system. If I knew he did a quality job then I wouldn’t have to spend an extra $1,5k for a maintenance package.
Thx any comments appreciated.
A 500sqft Bonus Room was added (house is now shaped like a “U”) and they tap the plenum to attach a 12” insulated flex line and run it 40’, then split it into 2 lines a 20’ and 5’, along with a 4ton Rheem Classic X. Now 30yrs. later its’ given up the ghost. The bonus room was never cool enough in the summer nor warm enough in the winter. The airflow was a trickle compared to the bedrooms.
Most recent ACtech said the whole plenum needs to be changed out because he noted a tapered transition from the evap coil to the plenum. Stating the 4ton wants to put out 1600cuft and the plenum is only designed for 1200cuft (the original 6 – 6” ducts. That makes sense and not questioning it, but this is where the story gets interesting.
I have already changed out all the windows (3 -1ea E, S, W- 5’x4’ and 2ea both S-18’x4’ to vinyl double pane a few years ago. And now want to change all the ducting to insulated and reflective R8, Air-Seal the 13 recessed lights and the rest of the attic, blow in or batt in R38 insulation and put in baffles and 1 AC powered (set to 110) thermostatic gable fan and radiant barrier foil. I also cut in a few yrs. ago about 500sq.in of soffit into the bonus room as it had none, but did have 1300sq.in. of dormer and gable vents. I think I need another 600sq.in. of soffit though.
I’m thinking the house could keep the plenum and work with a 3Ton 14 SEER single stage R22 or 16 SEER 2 stage 410 system. Problem is every contractor says 4 ton and won’t do load calcs. They just say they know. On top of that they only want to do the change out and not the ducts. I say I’m losing a significant amount via the metal ducting seems and they say it is not as much as the marketing people would like me to think. I read both sides about how it doesn’t actually blow out the seams but via the venturi effect sucks in dust and asbestos. I think it blows out the seams but willing to admit probably not as much as I was once thinking.
Should I keep looking for someone that will do a manual J or at least something similar? I have found a few free online calc but they are pretty rough, but do back up my cognitive bias that the answer is leaning in my direction more than away.
On top of it all they are all coming in around 14k-16 for 4Ton American Standard 16SEER 2 stage systems, with 1 outsider at 8,5k.
Lastly I heard and believe the saying, the most important day of a units life is the first day (commissioning). I understand this to be the technician taking his time, a fair amount of waiting, waiting for refrigerant to normalize, putting it in slowly/properly, wet rags where needed, torch technique (Schrader valve), basically proper procedures and that a fair amount of guys rush it which always hurts the homeowner and benefits them in the form of repeat business.
I’m trying to figure out how to protect myself from this. I don’t get to pick the tech that comes out to do the install with these big companies. And if you go with the small guy he likely hasn’t done as many jobs. But if he’s older, than he has done plenty jobs but could be retiring soon. So it seems the only safe way to play it, is pay for the “maintenance” package of $150yr for 10yrs. which additionally protects you because all these 10yr. parts and LABOR warranties are only good if you buy the maintenance package. I don’t like the idea of a tech hooking up gauges every year just to say it is fine. If he did his job and there are no factory defects and airflow is balance correctly, it should stay a closed system until it proves itself otherwise.
How long does it take to properly initially setup a system once it is installed? 3hrs? Is there a website, maybe a tech school pdf that might have the proper sequence of events. I got into this discussion with only one sales guy/comfort advisor and he said his company requires the techs to take pictures throughout the install so each step is time stamped. I don’t know if this is good or bad. I guess it is cya for the company in case of factor defects and hopefully less free truck rolls if the tech built a solid system. If I knew he did a quality job then I wouldn’t have to spend an extra $1,5k for a maintenance package.
Thx any comments appreciated.
source https://hvac-talk.com/vbb/showthread.php?2222116-Undersized-Ducting-and-over-sized-AC-typical-1955-3br-2br-stucco-box&goto=newpost
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