Yep, that’s why the manual J load calculation is so important to sizing the unit. In contrast, I have a 4-ton single stage 14 Seer unit for 2,465 ft2 living area (house built in 93), about 600 ft2/ton. R-13 walls and R-30 attic - southern Louisiana. I recently used a online J load calculator to estimate my needs and it calculated 3.5 tons so I currently may be a tad oversized with my current system. But I can truthlfully say I’ve not had any cooling/heating/humidity issues, but I’m not as likely as efficient as I could or should be.

But I will hire someone to conduct a proper blower door manual J load calculation and Manual D (duct sizing) to identify and correct any significant air leakage issues I might have in the house envelope, and potentially the duct work, before sizing and installing a new HVAC system.

FWIW, I’ve pretty much convinced myself to install a whole house dehumidifier when replacing the HVAC.

This post was edited on 5/12/19 at 9:25 am

1 ...

Report Post

Posted by notsince98

KC, MO

Member since Oct 2012

18098 posts

Posted on 5/8/19 at 12:43 pm to CrawDude

quote:
FWIW, I’ve pretty much convinced myself to install a whole house dehumidifier when replacing the HVAC.

Trying not to derail the thread and I know humidity is bad down there but do you think you need that? What indoor humidity levels do you regularly see now?

If you want just a tad better humidity control, I would highly suggest making sure your next furnace or air handler has an variable speed ECM blower with proper thermostat. You can set it up to reduce blower CFMs when humidity is above a setpoint. this reduces humidity faster and allows better humidity control during marginal cooling times.

Despite all that, a properly sized system set to 350CFM/ton would probably control your humidity very well.

1 ...

Report Post

Home & Garden - Replies to Post

Return To Board

Page 1

Return To Board