As a home owner you should be aware of what is involved in an air conditioning tuneup. If you read any home maintenance articles this spring, most will encourage an A/C tuneup; some will even claim 25% savings. Predicting savings without knowing what type of tuneup received is a little silly. Encouraging a tune up without explaining the difference between an average tuneup and a high quality tuneup is a shame and expensive.
Most tuneups claim to adjust, check, reset, or modify back to factory settings. What does that mean? It implies that when the service tech is done your system will be good as new. What it really means is that the ad is not very specific; tough to figure if you got your moneys worth.
First a little insight, the tuneup is the basic advertising model for most HVAC companies. The idea being they sell you a $59 tuneup hoping you're so impressed with the work that it will lead to a new furnace install when the time comes. Any professional HVAC company will happily service a customer for years just for a chance at landing the new equipment job. If that logic is stretched out the more tuneups the more future jobs so why not drop the tuneup price? Just one problem as price drops, pressure to do more tuneups per tech increases and the quality of the tuneup suffers.
What should a quality tuneup include?
- Measure airflow of system, absolutely critical for capacity and efficiency. Most air conditioners require 400 cfm of air to operate at capacity. There are three ways to measure airflow
- Static pressure measurement. This is the most accurate method providing the blower wheel is cleaned.
- A duct traverse. This involves drilling a series of holes in your return drop to measure air flow with a wand style meter.
- Tru-flow air meter. A measuring device installed in the filter slot. Some techs believe its accuracy drops with poor duct design.
- Temperature drop across the system is not an accurate measurement of air flow, while temp drop is important in diagnosing it will not accurately determine air flow.
- Clean the condenser. The out door unit should be sprayed with a heavy foaming cleanser that soaks for ten to fifteen minutes before rinsing.
Measure indoor and outdoor conditions. Indoor wet bulb, indoor dry bulb and out door dry bulb should all be measured. A qualified tech will have the tools for this. After all measurements are taken the tech should plot them on a sliding chart that will determine required super heat. Super Heat is an HVAC measurement that sets proper refrigerant charge.
- Adjust refrigerant charge, as important as airflow. After airflow is set, the condenser is cleaned and super heat is determined, the tech can hook up his gauges and set the refrigerant charge.
- Other useful measurements.
- Temperature drop across coil should be 18-22 degrees, this is universal.
- Temperature drop across outdoor unit. The tech will know this depending on unit.
- Amp draw of compressor:b this will depend on size of unit.
For any company to do this work correctly it will cost more than $59. Tell the dispatcher what work you want done and understand that it will cost more. If it costs twice as much as a junk tuneup it's worth it for your comfort and wallet. Some companies will only pull and clean blower wheels on a Time and Materials basis and thats okay. Now you can talk to your tech with out worrying about being bluffed into a bad job.