The next step was cleaning the cold air returns. He found a good spot to drill an 8” hole for his vacuum hose. The procedure matched the other air ducts except that when he finished at the two cold return registers he drilled several holes in the cold ducts in the basement and blasted air into them. Because of our houses age and the upgraded return system, I noticed that the main sheet metal return duct had no top but was just butted up against the ceiling in the basement. When he blasted air in, dust and crap shot out the edges along the ceiling. Once he finished that he removed the filter and “swept” out anything at the bottom of the return with his hand into the 8” hose.
Fast forward 1 year and 1 week and the circuit board that HVAC Service had installed has failed again. They came out and said that it failed from water condensation dripping onto it, so we needed to replace it and reroute the pipes to prevent future water damage.  That would cost double what I paid last year.  Why didn't they fix the problem last year at the initial repair instead of putting in a circuit board that was bound to fail again?!? They were strongly recommending that the furnace be completely replace for a huge fee to avoid the same thing happening again.  I paid $59 for them to tell me they didn't fix it right last year. This didn't feel right, so I sought a second opinion.
I even asked if this is something they don't do, as in services on a Saturday night.  I was told by the receptionist that they do and I would just be ok calling another company if they is not  part of their services. They again assured me someone WILL call me in 10 mins.  Well, unless their definition of 10 mins is never, then they got it wrong as I am still waiting to be called 5 days later.
Contact/Relay -- Relays are electronically controlled switches that activate the various components of your HVAC system. They manage everything from the power going to the motor to automatic dampers, humidifiers, etc. Most of them are controlled by the thermostat. The most common failure for a relay is being stuck in the "open" position. Separated from its assigned contact point, it fails to complete the connection and send the message to whatever it was supposed to operate. This failure usually occurs from use over time. Each time a relay connects and sends its signal, the electrical arcing from point to point eventually causes wear and tear.
What if you move into a 20 year old house and find that the people who owned it previously NEVER replaced the filter? It was so dirty that the HVAC system did not work at all. For most people - duct cleaning is NOT a waste of time or money. You must not have allergies. I have very bad ones plus asthma. It makes it very hard for me if I don't get it done every few years. By the way - the ducts get dusty just sitting there - especially without air going through them. Dust settles on them just like it does the furniture.
An alternative to packaged systems is the use of separate indoor and outdoor coils in split systems. Split systems are preferred and widely used worldwide except in North America. In North America, split systems are most often seen in residential applications, but they are gaining popularity in small commercial buildings. The split systems are a great choice for small buildings where ductwork is not feasible or where the space conditioning efficiency is of prime concern [20]. The benefits of ductless air conditioning systems include easy installation, no ductwork, greater zonal control, flexibility of control and quiet operation [21]. In space conditioning, the duct losses can account for 30% of energy consumption [22]. The use of minisplit can result in energy savings in space conditioning as there are no losses associated with ducting.
If you think duct cleaning might be a good idea for your home, but you are not sure, talk to a professional. The company that services your heating and cooling system may be a good source of advice. You may also want to contact professional duct cleaning service providers and ask them about the services they provide. Remember, they are trying to sell you a service, so ask questions and insist on complete and knowledgeable answers.

My heat pump/hvac system is not blowing cold air anymore, got checked out was told compressor broken. was told it cost  almost the same to repair/replace they recommend whole system. It's the same company that installed it 18 years ago, telling me that system is old and it will cost $9-10k for new system, because furnace has to be replaced with new hvac. what to do, need answers thanks????

The jury is out on whether or not cleaning your air ducts and vents has a significant enough impact to be necessary. A proven connection between immaculate duct systems and air quality in the home has not been made. However, if your vents display any of the signs listed above, cleaning would certainly be in your best interest. Allowing mold, debris and bacteria to fester could create bigger problems down the line. If having your system disinfected is within your budget, you may prefer to take care of these issues rather than ignore them.
All modern air conditioning systems, even small window package units, are equipped with internal air filters. These are generally of a lightweight gauze-like material, and must be replaced or washed as conditions warrant. For example, a building in a high dust environment, or a home with furry pets, will need to have the filters changed more often than buildings without these dirt loads. Failure to replace these filters as needed will contribute to a lower heat exchange rate, resulting in wasted energy, shortened equipment life, and higher energy bills; low air flow can result in iced-over evaporator coils, which can completely stop air flow. Additionally, very dirty or plugged filters can cause overheating during a heating cycle, and can result in damage to the system or even fire.
HVAC equipment is estimated to last about 15 to 20 years. Yet over the years, parts go out and need to be repaired. Heat sensors, exchangers, and ducts can become worn out. Air conditioning motors may need repairing from time to time. For repairs to your heating and air conditioning systems, and even general maintenance, let HomeAdvisor help. Enter your zip code and let us connect you with prescreened HVAC repair services near you.
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