Great site! Yet another not cooling question but its long. Any guidance appreciated... just don't say call in pro as I've done that to death.

Background -8 year old house, well insulated - low E glass throughout but, lots of it! including 6 skylights and vaulted ceilings. 2600 sq. ft. but more like 3400 sq. ft. if you consider room volumes- -basically an HVAC nightmare.

Being an engineer, I had my contractor, AND the supply house AND the manufacturer confirm equipment recommedations (which sounded inadequate to me). I believe the method used was IBR. The system is a Teledayne Laars hydro air - 1 hydronic boiler, 2 air handlers and 2 condensing units (spilt systems). Each air handler has a hydronic coil for heating and a seperate cooling coil (this is a conventional r-22 cooling system, not a chilled water system). High/Low returns in all rooms, fully insultaed duct work with velocity calcs done during sizing. Not a cheap system! Total system capacity recommended was 125k BTU heat & 5 tons cooling (2.5 up & down). I questioned both but was re-assured the science was right... trust it.

Well they were partilly right. Heating is fine, cooling has never been! Well at least not upstairs. Downstairs zone is acceptable but the upstairs zone can't keep up. Call backs always brought the same response - "you bought an ir conditioning sytem, not a refigeration system". The premise being that "slow cooling" is better than "fast cooling" for comfort... "its normal that if you turn the system on at mid day, it will not bring the temp down til after sunset becuase it need to get the humidity out first". The system needs to run 24 hours... you can't shut it off and turn it on when it gets hot! BUT, even leaving it on all the time, upstairs looses ground during the day sometimes getting 10 deg. F over set point during very hot days with all the shades drawn!

After a couple years of this same bunk and getting nowhere, I called another company in and without doing anything, they said "systems too small"... I dind't like the off the cuff answer and some others but got much the same...a guy that looks around the house, doesn't pull a panel or use a probe...perhaps they put a gauge set on the condenser and start with the "maybe this or maybe that" but no conclusives and the cath all "the syetms too small". When told that the calc were done by 3 different sources using IBR, they just shrug and smile as if to suggest experience is better than those fancy figures (who am I to argue... I'm the one with the problem).

The real problem - Laars no longer supports cooling -just heat so my air handlers are orphans. The cooling coil is 31K BTU and I can't get a larger one - I'm not even sure a larger one woould help as I think I may also have an air flow issue. To replace the air hadler altogether is tough becuase of the heating side and attic location.

any suggestions on improving the system and keeping the handler? Perhaps a 3 ton condensing unit coupled with trying to get more air flow through the handler...?