Making Duct Systems Work

[@spartan5106]

great info guys, thanks!

[@pilotrserra]

We (society) need more HVAC videos like this - comedy mixed with technical information. I enjoyed Ed’s comedic personality and stories …balanced with David and Bryan’s technical professionalism. You all are great teachers…thank you.

[@mattgruber3933]

Ed is sure right about larger ducts. I used 12" flex ducts for a 1 ton, and it works great! I put a $219 window ac in my attic loft and it cools 3 rooms. 7 years, so too late to tell me that it won't work. my 1st system too.

[@johnwhite2576]

HVAC school should convene this same group to discuss same topic on NEW installs

[@Portugalishere1998]

3:52, You talk about how It's all right to use multiple one inch filters in place of 1 larger filter, but that's wrong. Not only are you going to increase the MERV rating beyond the manufacturers specifications of the unit, but with the extra filters your adding, your adding extra surface area that the air has to pass through and thus creating more restriction in your duct system

[@Diabloshell]

Ive always been told this as well, maybe multiple lesser merv rated filters? Not sure if it works that way. Either way ive akways been told if you need a thicker filter, just put the smaller one in for now until you can come back

[@1ucapedia]

I don't see how the amount of filters changes the merv rating of the filter media. Also, the whole point of a 2", 4", or 5" filter over a 1" is to increase the surface area of the filter material, which will 1) potentially allow more airflow into the air handler, and 2) reduce the frequency of filter changes. Assuming the return ductwork is sufficient and merv ratings remain the same, how is there any difference between X total square inches of filter media on a 5" filter, or X total square inches added up between 5 separate 1" filters?

[@Diabloshell]

@1ucapedia I believe if you added surface area of five 1" filters and the surface area of one 5" filter, there would be a large difference. I don't think they add up. I'm betting maybe two-three 1" filters make one 5".

[@HVACS]

In parallel not in series

[@Portugalishere1998]

@1ucapedia if you have a 5" filter with an 11 MERV rating, and you replace it with five 1" MERV 11 filters. You now have a merv rating or 55, which is way above what would be necessary for the unit. And Okay let's say you use four 1" MERV 2 rating and one MERV 3 rated filter your still creating more restrictions in your system by increasing the amount of surface area the air has to move across.

[@JosephHileman-jx1zi]

Should there be a certain be balance in duct pressure (60/40)?

[@johnwhite2576]

Please expand why self balancing systems don’t work? Access aside Would you use dampers at start or end of a branch

[@Mrs.SusieDunn]

In my opinion I feel that it is better at the plenum

[@brockbeckstedt6483]

Duct sheet metal fittings are easily identified to being a high static loss fittings.

[@AJservicetechAZ]

Loved this a ton. (See what I did there)

[@brockbeckstedt6483]

Plus proper size duct then humidity water removal per hour in summertime will be felt.

[@jrgsxr33]

I found flex duct not supported properly thus effecting air flow. Simply property strapping the flex duct properly helped

[@PlumberGuy-ez9wx]

Ughh my attic is full of that sh** with 90s everywhere. I'm thinking of adding sheet metal 90s instead or hard piping from the trunk to the offsets not sure yet

[@johnwhite2576]

Can you have too much return??

[@Mrs.SusieDunn]

I was gonna ask the same thing!

[@MrsChip]

No, it’s nearly impossible to be too large, based on what they’ve said in the past.

[@mattgruber3933]

I'd say YES if it is running near the roof. On a really hot day having 120F around the duct will raise the temp of the return air. Size it right and pick up less heat. Most ducts are only R4 to R6 and they still transfer heat.