Just curious, as I think mine's on the lower end of what would be considered acceptable..

How can I measure it and is it cheap?

Do you just get a normal type thermometer (under arm...mommy I'm sick) or do you use a something specific for auto AC systems?

Absolute zero... I got me a rev D amplifier!

BTW, vent temp is meaningless without knowing ambient temp.

Just a reminder, this is about central AC, *not* the 8's (or any car's) AC. :)

For measuring vent temp I have this old thermometer I used in photography.. a meat thermometr, the kind you stick in the turkey or roast.

My delta T between room and vent is always about 12 - 15* F, I keep the room at 75 and get a vent temp of about 60 to 63. Ambient around here lately is mid-80's with insane humidity (for the last 2 weeks.)

The AC struggles to keep 75. 74 is not even doable anymore. it'll do 76 OK.

This thing used to do 72 without batting an eyelash, but herr landlord is giving me the runaround. Unfortuantely, I never measured vent temp when it did get the place down to 72.. wish I had.

Oops... With all the A/C complaints lately, I just glossed over the 'central' part. For central air, as in automobile HVAC, the temperature reading is meaningless without a reference. You should monitor the temperature at a return, and then at your registers, and see the difference. If you have 20 degrees, generally that's really good. Another good reference is to monitor at the main supply plenum just past the evaporator coils, and then see how much heat gain you have through your ductwork. If you want to know everthing there is to know about HVAC, there is an excellent forum at http://hvac-talk.com/vbb/.

Central air conditioners are very expensive to fix, if you have a compressor leak for example and need a new compressor.

Which it sounds like you are beginning to notice.

Hint: it gets more expensive the longer you wait to fix it.

-Speed (just bought two new air conditioners)-ER doc :(

I don't pay for the AC repairs.. one of the very few perks of being a renter ;)

The guy tanked it up with freon. Vent temp dropped 2*F relative to a given room temp. Better. 73 now achievable comfortably at night.

ALl of these are Rudds, they're all 20-25 years old, and all are starting to fail. Slowly but surely, and you can *hear* 'em in the middle of the night... seems to be they're expiring with bad bearings on the compressors outside.

One unit, left next to the dumpster for collection, was so rusted out it probably weighed about 1/2 of what it did when new. :eek:

Ours came with the house in '78. When we bought it in '99 we had the furnace (evaporator) coils cleaned and that helped a lot, but the unit is living on borrowed time. Had to add a "booster capacitor" because the motor just couldn't get started anymore. It's only a matter of time now. It looks awful and I can't believe it still works. The thing sounds pathetic if you're outside when it comes on. Probably shouldn't wait for it to die on its own, just out of courtesy to the neighborhood :rolleyes:

It doesn't quite keep up with the hot days. It gets up to 100 once in awhile and on those days the inside gets up to 80 or so, regardless of the thermostat.

I replaced my system last year with a full Carrier Infinity system - outside AC unit, a-coil, inside furnace, the works. This is on our main zone - the house has two zones - the main house and the addition, which has our master suite, was built in 2001 (not by us) and it has it's own AC and furnace (and damn, that is one nice feature to have!).

The Carrier I got has a DC-motor compressor and fan that gives it infinite variable output of both air and cooling. Additionally, it has a zone damper box above the furnance, and thermostats in two additional areas of the house - the bedrooms on the 2nd floor, and the family room. The compressor runs a fair amount more than it used to but also dials up and down a lot - really slow on the compressor when it just needs a bit more cooling to complete the job upstairs, faster and high output when it kicks from 75 degree "day" temp to 72 degree "evening" temp.

During normal "maintenance" running, it's at about 55 degrees coming from the vents, and even warmer upstairs when the compressor slows to finish the upstairs and the downstairs is dampered off. When it's in cool-down/temp change mode, it blows a freezing 44 degrees from the vents - amazing how cool it will blow.

The refrigerant is Carrier Puron, by the way.

All told the system was about 6 G's but totally worth every penny in terms of comfort and energy efficiency.

we paid 12K about 3 years ago for a total replacement AC/Furnace. Got the top of the line trane (18 seer) at the time.

Best money spent ever. the MBR (2nd floor) stays at 72.

this is about central AC

Ohhhhh...lol, sorry...