airflow

[beenthere]

No, didn't miss it.
But if they're sizing the ductwork like that, figured they might be sizing the house that way also.

[markk2]

The house is apx. 2700 sq. ft. In this part of the country (the Pacific Northwest) it usually figures about 700 sq ft per ton and 20 btu's per sq ft.

[beenthere]

Have you convinced them yet.

[markk2]

Not yet. Sometimes its hard to get experts to realize they may be wrong. In this case I gave them all the numbers and suggested that we need to increase the airflow to decrease the static pressure and since we are already in the crawl, possibly change ductwork to actually deliver required airflow for comfort. They act like I am attacking them personally. Incedentally, I have been in HVAC for 40 years so I have learned a few things, one is RNC design is usually not correct.

[dash]

If you haven't already you need to show them the actual cfms being delivered,using the manufacturers fan data chart.If you don't have it or need help with it post the brand and model numbers and someone can assist you.

There are several ways to reduce the static by remediating the duct system,rether then replacing it.If you show them the cfms ,before and after ,it might be convincing.Again more info., about the static,supply versus return,and the actual duct system sizing and layout,and you can get some assitance here if you need it.

[beenthere]

one is RNC design is usually not correct.

LOL.

Yea, I started out in RNC 33 years ago. Corners were cut where ever they could. And many they shouldn't have.

[markk2]

I've pretty much done all that. I guess I'm venting more then anything. It helps to know there are techs out there that realize the situation. I have spent most of my life trying to make the company I work for better and more professional. When the brick wall you run into is higher then you can jump, chip away. You might make a hole.

[dash]

I've pretty much done all that. I guess I'm venting more then anything. It helps to know there are techs out there that realize the situation. I have spent most of my life trying to make the company I work for better and more professional. When the brick wall you run into is higher then you can jump, chip away. You might make a hole.

Someone there must be very hard headed,if after proving it that still resist.

My hope was a duct remediation could be designed ,and then installed at a very low cost and they would see the difference,and realize the importance of design and install from the start of the job.

With the air flow you have,you can show the loss of btus,and what it's costing the homeowner.Maybe you can find a competitors job and sale them duct redesign.