New Gas Pack System problem

I've just got my Dec gas bill using my new Carrier gas pack system and wondered if the amount consumed is normal for this application. We have a 4500 SF new construction home with a 5-ton gas pack for the first floor, a 3-ton split unit for the 2nd floor and a 2-ton gas pack for the basement. I set the Thermidistats for 68 deg F during occupied, active hours (5:30 am-8 am, 4-10 pm M-F, and 6 am-10 pm Sa-Sun) and 65 deg otherwise, and the humdity levels for 40% RH in winter and 55% RH in summer. The Dec usage was 450 units (x100 per the meter) which averaged out to 15 units/day. At $1.78 per unit, the cost was astronomical. Needless to say I'm having sticker shock! I've had the gas co. check the meter with no results and now, I am working with the installer to check out the system. Am I wasting my time?

Our home is in north Alabama.

 

move into one side of the home for the winter.
that size home your bill must be astronomical.

 

You've got 10 tons of cooling for 4500 sq.ft !! I'de venture to say that's a tad bit too much. What are the btu ratings on each ??

 

You can probably discount the 2-ton unit for the basement since it rarely ever is activated which leaves 8 tons for the remainder of the house.

But to answer your question on ratings, the 5-ton has an 81.9% eff rating and the 3-ton has a 92.7% eff rating. It looks like we have a mismatched system for the main living levels. I wasn't involved with the HVAC system selection - that was my hubby's job during the build process and it looks like there may be a mistake involved aside from the "normal usage" question I have.

 

lmsjfs

Based on the info you provided, I would say with some confidence that your systems are vastly oversized probably from 20-33% too many BTUs. And you might expect some comfort issues next summer with AC cooling/ dehumidification. Gas is no longer a value fuel for winter heating plus I see where you live in N Alabama which would seem an ideal location for heat pump systems-I would think Alabama has good electrical rates. The decision of placing an 80% eff gas pack system for the main floor which is probably the primary living area also seems questionable. You may want to consider having a word of prayer with your husband and building contractor. Besides the dubious decision of a package unit which I do not care for(unless there are installation/application issues), I would want to find out who was responsible for sizing the units and make them show you the written calculations for each floor. I would start on the first floor.

Sorry for your trouble but I doubt there is an easy solution here other than starting over.

My Opinion!