Hi. I'm looking to replace my current 15-year old 3.5 ton furnace/air conditioner. The current system cools well, except for an upstairs loft. The loft only has one small air duct, and has windows facing the afternoon sun, so it can get toasty up there in the summers. I live in Indiana, so 90+ degree days are common in July - August.
I've had a well-respected local contractor out to quote a new system. He's suggested that I go with a larger air handler/furnace to increase air flow to the loft. Specifically, he's recommending a 5 ton furnace mated with a 3.5 ton air conditioner.
I've never had any heating problems with the current 3.5 ton system, so if I went with the larger unit, it would only be to increase air flow to the loft in the summers.
The higher temps in the loft are a nuisance, but not a big one. I'm OK spending a bit more on the system if it improves the air flow, but it's not a big enough deal to justify installing new duct work.
So...the questions are...do you think the 5 ton system will help improve the air flow and other than the installed cost, what is the downside to having a slightly oversized furnance/air handler?