Upgrading Second Floor (attic install) HVAC performance


Old 01-22-17, 08:04 AM
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Upgrading Second Floor (attic install) HVAC performance

Hi Guys,

I'm looking for some help here and maybe a reality check.

My house has separate unit (basement/attic) supplying the first and second floor respectively. The 3 ton for the first floor (1800 sq ft) and 2.5 ton for the second floor (1500 sq ft).

The second floor is not keeping up on hot days and flow to the distant rooms is weak. I've tried increasing fan speed with little improvement and now rooms (Master suite) closer to the handler are cold. The system uses one large return in the hallway with supplies in each room. Long story short, flow is not optimized. The ducting is old ductboard, some internally insulated rigid, and some flex. Its old and hodgepodged together.

I've had a couple HVAC techs over to bid out fixes/upgrades. All tell me to ditch the central return in favor of returns in each room. This makes sense. I was also given the suggestion of zoning out the master suite from the remaining rooms. This too makes sense too and is something I want to do.

Prices range from 6-10K just to redo the ducting. This is insane! Another 4K for separating out two zones... Insane???

This is an exposed walkup attic with unlimited room to work with.

Okay, DIY time, and where I need a fact check. I'm a very handy guy and have experience with plumbing, electrical, framing, renovations, finish carpentry, etc etc. I have tools, I am capable, and willing to learn anything. I pulled the engine on my wifes Subaru to change clutch and head gaskets. My point is, I am good at doing things given I have ample resources to learn and I buy the correct tools for the job.

Before throwing out 13K to replace duct and add a zone, I'd rather take a stab at it myself. Is tis doable? Am I crazy? I think not, but you guys know more.

I'm happy to draw up room diagrams with measurements for system design, and purchase materials for installation. I have a rough idea from the proposals Ive received how the system would be laid out. I'm not afraid to cut holes in ceilings, snake thermostat wire, install zone controls and move wiring. The only thing I cant do is drain a system and fill a system should I need to move the AH...

What do you guys think? should I proceed or turn back?

All help is appreciated.


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Old 01-22-17, 06:25 PM
Houston204's Avatar
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Join Date: Oct 2009
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Some sheet metal and tin snips would allow you to make some dampers for the ductboard. Reduce the airflow to the master bedroom to force more air to the far rooms.

The large snips is what I would use to cut the tin.
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