Need Help With HVAC Decision

[HarryHomeowner1]

Kindly share your expertise and knowledge regarding the following:
Home:
3400 sq. ft., 2-stoiry, full sun exposure, facing West, gas-hot air heat, existing system is 19 yrs. old, R-50 insulation in 2/3 of attic, R-19 in remaining 1/3, house located in Phila., PA area. Existing system is Bryant 90+ AFUE, 132,000 BTU Furnace and 4 ton condenser and coil. The a/c struggles to cool the house on the hottest summer days and I have always wondered if a/c was undersized by the buider.

System Choices:
1. Rheem RGRM-10EZAJS, 105,000 BTU, 95% AFUE two stage, variable speed, furnace, Rheem 14AJM56 14.5 SEER, 54,000 BTU Condenser, and RCFLHM60 5 ton Coil. Price - $XXXX.

2. Lennox EL296UH110XV60C, 110,000 BTU, two stage, Variable Speed, 96% AFUE, furnace, Lennox XC17-060, 15 SEER, 5 ton a/c condenser unit, and Lennox CX34-62D-6F Coil. Price - $XXXX.

Your advise/input is most appreciated. I think I have two pretty good choices, but need your help in making final decision. The prices are the same due to price matching. Any other suggestions/input?

Many thanks,

[beenthere]

Define struggles to cool the house on the hottest days. hottest as in when its 98 or above, or when its only 90 to 85? Does it just run all day while maintaining temp, or does the house gain temp.

[HarryHomeowner1]

Runs without cycling mid-day when outside temp > 90 or 95. Can hold 80 indoor temp, but struggles to drop temp if set to drop below 80.

[beenthere]

When its 98 outside, mine runs non stop for 6 hours at a time. Mine however will maintain a lower temp. If I set mine to 80 on a 98 degree day and let it get that warm/hot inside, and then set it to 72. It might drop the temp to 72 by the next morning.

How much additional duct work did they say they need to do/add in order to install the 5 ton. Your duct work isn't gonna be big enough for 5 tons. And may be a bit small for the 4 ton unit you have already.

[HarryHomeowner1]

All contractors that have looked at my system and measured the ductwork, assure me that I have adequate ductwork to handle 5 tons... they universally agree on this.

[beenthere]

LOL. And i bet not a one of them measured the static pressure that the 4 ton was running at.

You can find lots of threads here, where people were assured that here duct work was big enough for a large unit. And after he install, they have noise troubles, and or the A/C freezes up.

Its possible your one of the lucky ones that a HVAC contractor installed duct work 20% larger then he needed to for some unknown reason.