Be careful of dishonest HVAC contractors. There’s no magical formula to see if an HVAC contractor is scamming you, unfortunately, but remember that they typically do this in one of two ways: first, they are charging grossly low prices (far below everyone else), or second, they aren’t including what everyone else is. In the first situation, they will charge you change fees, other hidden fees, or they stole the equipment and are passing themselves off as legitimate contractors (very common in California these days). In the second situation, they are charging you a very fair price, but aren’t including what the other contractors are (i.e. charging $10,500 for the installation which is fair, but not including the ductwork which is a scam unless there is some other, complex stuff going on there).
I just had my blower module replaced because my AC coil was frozen over. The underside of my coils had a thick mat of dust because I had never had it cleaned. I cleaned it myself by using a soft brush attachement on a shop vac. The inside of the blower appears to have a white/green growth, and I am sure the ductwork of my 30 year old house can’t be in good condition.

Moisture can enter the duct system through leaks or if the system has been improperly installed or serviced. Research suggests that condensation (which occurs when a surface temperature is lower than the dew point temperature of the surrounding air) on or near cooling coils of air conditioning units is a major factor in moisture contamination of the system. The presence of condensation or high relative humidity is an important indicator of the potential for mold growth on any type of duct. Controlling moisture can often be difficult, but here are some steps you can take:

Free cooling systems can have very high efficiencies, and are sometimes combined with seasonal thermal energy storage so that the cold of winter can be used for summer air conditioning. Common storage mediums are deep aquifers or a natural underground rock mass accessed via a cluster of small-diameter, heat-exchanger-equipped boreholes. Some systems with small storages are hybrids, using free cooling early in the cooling season, and later employing a heat pump to chill the circulation coming from the storage. The heat pump is added-in because the storage acts as a heat sink when the system is in cooling (as opposed to charging) mode, causing the temperature to gradually increase during the cooling season.


In modern buildings, the design, installation, and control systems of these functions are integrated into one or more HVAC systems. For very small buildings, contractors normally estimate the capacity and type of system needed and then design the system, selecting the appropriate refrigerant and various components needed. For larger buildings, building service designers, mechanical engineers, or building services engineers analyze, design, and specify the HVAC systems. Specialty mechanical contractors then fabricate and commission the systems. Building permits and code-compliance inspections of the installations are normally required for all sizes of building.
Cost Factors: The size of the unit, its efficiency and it’s single-stage, two-stage or variable-capacity are the top cost factors. Features like communicating technology and improved dehumidification performance also affect the price. Learn more about communicating technology here including the pros and cons, before being agreeing to a communicating system.
What about ringworm? If the fungus is as contagious as doctors warn, and the spores can live several months, doesn’t it make sense to spray some sort of fungus killer into the HVAC system to kill the spores that it has sucked in from the air? Duct cleaning would not be helpful at all here; these spores are microscopic and it could actually spread them further. But given how severely contagious ringworm is, body and especially scalp, does anyone make an aerosol product that will clean the system and kill the fungus? One the resident can use, not call an HVAC company; you can’t do that when you are in an apartment. I hear it’s not the same as mold, it is much more difficult. Truth?
He proceeded to clean each heat register by removing the grille and blasting it with an air pressure hose toward the duct opening thinking that the dust would magically be sucked inside. In one room this caused a ceiling smoke detector to go off because the excess dust fooled it into thinking there was smoke. I put my hand in front of a register he wasn’t working on and could hardly feel a suction. Although we discussed how I open and close damper doors, I realized later that he never checked, opened or adjusted them during the cleaning. He could have closed all but the one he was working on in order to increase suction results. His next step was to blast air into the duct and then attach a “squid-like” device that slapped around inside the duct as far as he could reach. This is important! In a newer house, ducts have long straight runs from the furnace. In older houses like mine they can turn and twist. In fact, the duct we have a problem with runs straight up from the basement inside a wall and turns 90 degrees into a soffit for three feet then into two 90 degree turns to get into the floor joist area for another two feet and finally a 90 degree turn up to the second floor register. When he cleaned this one he could only get three feet into the register with the hose or squid because of the turns. That was the case with most. Hardly what could be described as a decent cleaning.
Heating, ventilation, and air conditioning (HVAC[1]) is the technology of indoor and vehicular environmental comfort. Its goal is to provide thermal comfort and acceptable indoor air quality. HVAC system design is a subdiscipline of mechanical engineering, based on the principles of thermodynamics, fluid mechanics and heat transfer. "Refrigeration" is sometimes added to the field's abbreviation, as HVAC&R or HVACR or "ventilation" is dropped, as in HACR (as in the designation of HACR-rated circuit breakers).
The fact is if they are dirty why not clean them. As for the Dr’s comment about if it is not disrupted it is fine. As a pet owner sometimes un disrupted pet hair will sit in the corner of a room or under a counter un disrupted but I still clean it when I notice it. Just because you cant see it doesn’t mean you should leave it there to collect more and more. The people that don’t want there air ducts clean either simply cant afford it but would like it done. OR! the crowd that are to cheap.. You should Clean all portions of your house.
Hi guys if your not convinced yet that duct cleaning is a waste of time. I’m a HVAC business owner install heaters and air conditioners. Simple facts if you have an old system get a new return air fitted with a filter it will catch all the dirt and dust. If you still have as many do black flecks and stuff coming through it is the lining inside your ducting that has perished. So somewhere you have a hole or very old ducting. If you had rats etc its a hole somewhere. To clean, stick your vacuum in the outlet and push the hose as far as it will go this gets 99% of toys and coins fur and alike. Think about it if the object is not heavy it will come out the duct when unit is on. Service the heaters or air con units but not the ducting. I would go further to say that duct cleaning actually damages the ducting in my opinion.
In reading through all this about duct cleaning, THE ONE preventative measure people need to realize is that a poorly installed HVAC system that is not sealed and air tight to ensure that ALL indoor air passes through a GOOD air filtration system IS THE best means of ensuring your ducts remain clean. Duct cleaning does not now and will NEVER improve an HVAC systems efficiency. Proper maintenance and installation are the key just as improper installation practices allow for dust infiltration into the duct system. I am a state licensed contractor in Texas, and unless people have their hvac system sealed and/or properly installed, duct cleaning is an absolute waste of money. My duct system is 12 years old as is as clean today as the day I installed the system with ductwork. SO before ANYONE jumps on the bandwagon of duct cleaning, get with your hvac professional FIRST.
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.
ISO 16813:2006 is one of the ISO building environment standards.[31] It establishes the general principles of building environment design. It takes into account the need to provide a healthy indoor environment for the occupants as well as the need to protect the environment for future generations and promote collaboration among the various parties involved in building environmental design for sustainability. ISO16813 is applicable to new construction and the retrofit of existing buildings.[32]
If there is stuff in the ducts, the fact that it’s laying there and not being blown into the rooms is proof positive that it is hurting no-one. The 5-6 exceptions you cite in this article I’ll buy, but only with the caveat that at least some of those could have been avoided by proper protection (during remodeling for example) – and if asbestos/lead/whatever winds up in your ducts- the remodeling contractor should be the one paying to remove it.
Undertaking an AC installation in Fort Smith, AR? The first thing to remember is that your air conditioning unit will need repairs now and then to remain efficient. Granted, many repair emergencies can be avoided through proper maintenance procedures. When your AC fails we provide reliable, affordable repairs of the highest standards. Enhanced efficiency and longevity is the name of our game.
Roof-mounted systems have the heating and cooling systems in one cabinet. Sometimes called "gas packs" (if the heater uses natural gas), they typically cost less than a comparable split system. In dry regions, most homes originally had "swamp-coolers" installed. When replacing them with HVAC systems, it's often cheaper to use existing mounts and ducting.
Venice warns homeowners to beware of air duct cleaning scams, especially the sort where unscrupulous cleaners offer a $49 special deal but start piling on extra fees. “It’s a bait and switch scam where they say they’ll offer unlimited cleaning, but then they throw around terms you might not understand, such as extra fees for a ‘main duct line,’” he says. “And many times, these cleaners end up walking out the door with twice the amount of money a reputable duct cleaner would charge. They’ve gotten very sophisticated at upselling.”
Our unit is 16 years old and we've had it checked out recently since it seems to be running excessively. Over all the tech says it is putting out well; it's the correct size, we have no shade and we've been having extreme heat with high humidity. The info you provided is very helpful and will help us make an informed decision when the time comes. Thank you so much.

My Carrier furnace occasionally (one-two times a day) does not start. It shows error code 15 ("BLOWER MOTOR LOCKOUT -This status code indicates the blower failed to reach 250 RPM or the blower failed to communicate to the variable speed furnace control within 30 seconds after being turned ON in two successive heating cycles."). However, when I turn off and on the furnace power switch it starts and runs fine for a while. Sometimes it runs fine all day, but does not start only once in the evening or in the night. It is 13 years old I was thinking to replace whole thing if repair cost is too high. But I am not ready to pay $10,000. 
Energy efficiency can be improved even more in central heating systems by introducing zoned heating. This allows a more granular application of heat, similar to non-central heating systems. Zones are controlled by multiple thermostats. In water heating systems the thermostats control zone valves, and in forced air systems they control zone dampers inside the vents which selectively block the flow of air. In this case, the control system is very critical to maintaining a proper temperature.

Hello, I read your comment and I know it was two years ago but I hope you see my message. I am trying to figure out what to do as I was told that there is some cat odor in the finished basement. I think with the air conditioning running that it may carry odor. The litter boxes are always kept clean. I wonder if odor can be trapped in the ducts, if Air Duct Cleaning could help, but it is quite expensive plus I'm concerned that it may not help. Please elaborate as to why you think it doesn't work that well. Do you have any other advise? Did you work in the field of Air Duct Cleaning? Thanks so much!
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