DIY Home Improvement, Remodeling & Repair Forum > DIY Home Improvement > HVAC > AC 2nd floor warms up during the day

Help Support House Repair Talk by donating using the link above.
Thread Tools Search this Thread
Old 06-27-2010, 04:34 PM  
Junior Member
Join Date: Jun 2010
Posts: 1
Default AC 2nd floor warms up during the day

Problem: 2.5 ton unit, 1400 square ft upstairs, I live in Lutz Florida. During the day the longest runs start to warm up (in other rooms), temps 82-86 degrees. AC working fine, at night I can drive the temp to 68 degrees.

I have had ridge vents installed, a solar vent, I have more venting than than spec. The attic space is no more than a crawl space, the AC ducts are running almost at the top of the roof line (I have tall gabled roof). The ducts are flexible and I cannot keep the upstairs cool. I have had AC guys out to look, all want to put in a 3 or 3.5 ton unit to replace the 2.5 ton.

I am looking at radiant barrier installation but the roof is so close to the ceilings (the inside ceilings are gabled like the rook outside, they match within a foot or so at places with a 3 foot gap at the top) I am not sure I can even do it. I though about using metal straps to box in the ac ducts, cover partially with radiant barrier, blow in insulation, then complete covering the ducts with the radiant barrier.

I am at my wits end, any help/suggestion would be greatly appreciated.


rbrodbec is offline  
Reply With Quote
Old 06-29-2010, 09:33 AM  
Junior Member
Join Date: Jun 2010
Location: Wilmington, Delaware
Posts: 16

Hey, I just signed up and saw your post.

I had the same problem with my new house, it had a cheap A/C system to begin with, but I added more fans in the attic.

I added one electric and that actually cost me some loot each month, I removed the electric fan and installed 3 solar powered attic fans. I have Ridge vents that the house was build with along with the soffets.

I am not sure how hot your attic is, mine was crazy! I also laid down 3 inches of the 'blow in' type of insulation, this made a world of difference even with my crappy A/C unit.

You may need a bigger A/C unit or maybe even a dual zone system, but honestly, I would make sure that your attic is WELL vented. I live up in Delaware and my 2 story house has an attic size of about 900sqft. The tallest point in the A style roof is about 8 to 10 feet.

I also went and installed a solar powered attic fan above the garage in that attic and that also made a difference.

Right now, I have a gable end fan at each end, and one in the center through the roof.

Florida is crazy hot, so I am not even sure what you will need.

BTW: The Solar fans run in the winter too, as the electric will only kick on with heat or humidity. This way it will bring the warmer air in during the winter months for those of you who do not live in florida.

I calcualted about a 40 dollar savings each month and noticed a difference in a matter of hours as to the temp upstairs.

Good luck

Last edited by silentdub; 06-29-2010 at 09:35 AM.
silentdub is offline  
Reply With Quote

Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Similar Threads
Thread Thread Starter DIY Home Repair Forum Replies Last Post
Enlarging a room: Floor is poured concrete with different floor elevations. jedblack Framing and Foundation 4 09-08-2015 06:01 PM
Sagging 2nd Story Floor After Main Floor Load-Bearing Wall Altered Below Ever111 Framing and Foundation 37 03-16-2015 03:46 PM
Installing tile floor using Ditra and heated floor mat joeyL Flooring 5 02-03-2014 07:44 PM
Sistering floor joists in my hunting cabin to stop floor movement NWCO2 Framing and Foundation 10 05-20-2013 10:21 PM
Resurfacing Concrete Floor & acid stain floor SPISurfer Flooring 13 12-18-2008 02:54 PM

Newest Threads