Hello, experienced masses....
I am selling my home and have fixed everything that has been asked by the prospective buyer and the city so far but am having difficulty with the buyer's inspector in regard to his A/C performance spec.
The inspector told buyer that the temp drop from return vent to evaporator test point was 10 degrees. The buyer was told that my A/C system isn't performing as it should. I verified his finding of 10 degree drop after they left with MY thermometer. I'm not arguing his number or his method. Please read on to see what I AM arguing about (to myself).
The temperature outside at that time was only 75 F. and relative humidity was 70%. This is a pretty cool day for St. Louis in July. It was also overcast with virtually no sun. It was only 10 Oclock am and with no sun load, the house was quite cool. My probe-style thermometer read 68 degrees on my kitchen counter and in the return air duct. I think its accurate within 1-2 degrees. I believe it to be relatively accurate in terms of temperature differential, atleast. So as stated previously, I put the thermometer in the same test point as the inspector did with the system running and got 58 degrees. The magic delta figure to fail a system and scare a buyer seems to be below 15 - 17 degrees from what I've gathered in talking to realestate agents and dealing with several home inspections. But don't you have to take into consideration the temp and humidity and solar load to some extent before interpreting delta temp?
I just happened to have an A/C company out two weeks ago to give my system a performance test so I would be armed with a professional opinion on paper before negotiations started. This is because the previous owner had several big dogs, and apparently their big bladders found the warm condenser fins a common target. (I was told that dogs' urine is a common cause of condenser fin errosion). The missing fins in one lower corner area coupled with some rust on the thin cage that protects the condenser make the outside unit appear old and worn to be sure. It isn't a great selling point visually. But this house isn't the fricken' Taj Mahal either. I don't feel that someone can use the APPEARANCE of my A/C unit to demand $2000+ for a new one IF IT WORKS!
The A/C guy I hired wrote that the temp change was 18 degrees, pressures were normal and that 'system was operating normally at this time'. It was about 85 degrees out and sunny that day and he did the work around 2 pm. I tested the temp drop several days before he came out and actually got 21 degrees but I can't remember the temperature or sun condition then.
So how do you all feel about the accuracy of DELTA for the purposes of condemning an A/C system? Do I really have a problem? Or may the inspector have seen that the unit was around 15 - 20 years old with fin damage and just found an easy way to condemn it that isn't accurate? (much less than 5% fin damage)
I feel that for my 900 sq ft house with full basement (all cooled with ductwork) and poor insulation my electric bills are reasonable. I also feel that the A/C FEELS cold and the system has never been charged in my 8 years here. I mean, 58 degree temp in the furnace ductwork can't be that bad can it?
I thank you all for any responses yay or nay!!!
Tony