I worked for United Air Comfort out of the San Bernardino Office for 4 months. To be able to troubleshoot and repair a heating and a/c system, you need to have more than a basic knowledge of electrical, electronic and plumbing.
I've been working with electronics, residential electrical and heat & a/c units on and off for the lst 20 years. I don't believe the any of the new people hired in my shop had any electrical or electronic experience before they were hired. One individual aquired his a/c training while he was in prison.
The company would give you 3-5 days hands on training (mostly cleaning ducts) with a trainer who didn't know any more about the complexities of a system than the person he was training. Yes there are several techs out there that are conciencious about their work, Like me, they don't make very much money with United Air just like I didn't. I had to go behind 'company certified installers' to repair their sloppy work. Sometimes I would get paid for the warranty work, most of the time not.
On more than one occasion, I was the 6th or 7th tech to be sent to a job because the system wasn't working correctly or not at all. These a/c techs would get thei EPA certification after two weeks or so of video training and then be let loose on the customer. As I stated earlier, Not all of the techs are completely incompetent, But when 90%+ of the new hires are let loose on their own with little or no formal training (by the way, the shop managers don't know much about the business either), somebody is going to get screwed, usually the customer.
Yes, United Air Comfort has a Tech Support System at the end of a 800 number, but that tech cannot see the system you are working on, and if you don't know what you are doing, the tech support is't much help other than telling you to sell the customer a new system. I'd been to several jobs where the tech before me changed the wiring.
There wasn't even a schematic to guide me. The tech support couldn't help the last tech so they had to send me there for another free job. I was the 4th tech on that job. Most of the techs don't even have the toole to do the job never mind do it correctly. Most of the serious problems are overlooked because the techs don't take the time to look for them. In order for me to make any money for myself, I had to charge an outrageous price for my services. This was due to the very low 25% commission. Other companies paid 35% to 45% commission, allowing a savings to the customer and both the company and techs make some money.
It's probably the only company pays you to learn the heating and a/c business, at the customer's expense. United Air Comfort reminds me os a multi level marketing scheme. A lot of nobodies making a little money for themselves and a bundle for the company.
I think I rambled on enough about United Air Comfort. The bottom line is if you need service, don't all on the $19 - $29 ads, look in the Yello Pages (you won't fine United Air Comfort there), ask your neighbors for a reference, don't call United Air Comfort.
If you change you filter often, before it gets super dirty (about every 3 months) with a good quality disposable or washable filter ($10 - $50) your system and home will be less dusty. Don't use the 99 cent filters, they don't filter out any of the allergens. Have your system checked every year before the cooling season, your system should be checked for refrigerent leaks and cleanliness.
Good Luck and God Bless