An important component of natural ventilation is air change rate or air changes per hour: the hourly rate of ventilation divided by the volume of the space. For example, six air changes per hour means an amount of new air, equal to the volume of the space, is added every ten minutes. For human comfort, a minimum of four air changes per hour is typical, though warehouses might have only two. Too high of an air change rate may be uncomfortable, akin to a wind tunnel which have thousands of changes per hour. The highest air change rates are for crowded spaces, bars, night clubs, commercial kitchens at around 30 to 50 air changes per hour.[17]
I noticed a lot of negative feedback, though unfortunately there are many dishonest companies out there. I currently work with a company that cleans duct work and we DO NOT use any scare tactics or up sell services or equipment. Once every 10years of course there are exceptions. We clean supply, returns, air handler, housing, motor, and fan. Though be discerning when qualifying anyone to work in your home. I would ask for REAL REFERENCES to contact.

The cost to replace a central air conditioner is about $5,000. However, this price varies depending on the size of your home and the difficulty of the project. It can cost as much as $12,500 to replace an AC unit. The labor required to remove and dispose of the old system adds to the price. The size of your home, brand of AC unit and ductwork complexity can all raise the cost as well.
I was with you until you said avoid steaming cleaning or moisture, there is no way you can remove mold or any other type of biological without moisture. The best way to do this is in fact with a steamer using a commercial disinfectant and a non reactive odor remover so your home smells refreshed and not like a hospital . This is directly contradictory to your article.
Having the most energy-efficient system ever built won't matter much if it's not maintained. Lack of maintenance is the number one killer of HVAC systems. Before each cooling season, it's recommended that your system get a professional tune-up. However, there are things you can do in the meantime to make sure your system runs efficiently throughout the year.

I hope that those customers you have with breathing problems don't follow your advice too closely. You are doing them a disservice. Dirt in your ducts does not always stay there, depending on what the contaminants are. I bet you tell your customers not to worry about mold either- just to kill it with bleach. Educate yourself before opening your mouth- You may kill someone someday with your opinion.

20 yrs ago I bought the house I am in and a Central H/A was installed at that time. At the beginning of ea season I have the unit serviced. Every yr since I have owned the house I have had to have freon added and been told that I must have a freon leak. Fast forward to this yr when I hired a new company to do the service. They went up into the attic as part of their overall servicing. Nobody else has ever done that. He came down showing me pics on his camera phone of ducts that were not even connected to anything and in my estimation have probably been laying there for 20 yrs. Of course he fixed this. I have not needed freon this year either. I have been complaining to friends about the huge amount of dust and how I can't keep up with the cleaning away of it for a long time. Now it makes so much sense.To me it is like that duct work was just up there laying around and every time my unit was blowing, all the insulation, debris, dust and whatever else over the years was just randomly filling up those ducts. What now that they are re-connected? Will it be better? Or am I someone that needs to have my ducts cleaned? I am so confused after reading all these comments. Can one of you experts tell me what you would do before I spend a bunch of money that I don't really have? Thank you for any input you can provide. Also, feel free to respond to email address denise@digitalflak.com

There are many interesting comments from several informed individuals. The question that has not been answered is how do duct systems get dusty and dirty? As a RESNET Home Energy Rater, I perform pressure tests on homes and duct systems, and the one common thread is . . . most air delivery sytems have large amounts of air leakage. The solution is to seal the duct system, and pay particular attention to the return duct system and ductwork near the air handler (the 'blower'). As others have said, a captive (sealed) duct system with proper filter maintenance should be more then adequate for most occupants. For those who have allergy, asthma, or other breathing problems, a filter with a higher MERV rating (number should be listed on the package) or a HEPA filter are good choices. These filters will capture smaller particulates and should improve the indoor air quality. Again, make certain that the entire duct system is sealed, preferably with mastic, second choice UL-181 foil tape - never use cloth duct (also known as duck) tape.


Fuses -- Anyone who has worked with electrical systems knows all about fuses and how they fail. They can burn out over time, may just be loose, or can blow out during an electrical storm or due to overload from another failed component. Of course, that's what they're supposed to do; they stop surges from going through and damaging the rest of the system. When a fuse fails, whatever system it was protecting will stop working.
On the other hand, if family members are experiencing unusual or unexplained symptoms or illnesses that you think might be related to your home environment, you should discuss the situation with your doctor. EPA has published the following publications for guidance on identifying possible indoor air quality problems and ways to prevent or fix them.
They were quick to come out and diagnose the problem with my furnace, but I thought the estimate of $549 a bit high to replace the circuit board.  So called around and found Leo's Appliance in Concord that sells appliance parts and the circuit board was only $90.49 - that is the retail cost to me, so I imagine the wholesale cost is a lot less.  So BEWARE of this company since they wanted $500!!! to replace the circuit board which is located right in the front of the furnace - extremely easy to access.  I hate it that you cannot trust repair companies.
I’m having my duct work cleaned this Saturday. Have a coupon for $49 through Amazon. Job normally $249. Had my basement remodeled about 18 months ago. The contractors were very thorough at blocking the vents, as far as I can tell. The offer is for HVAC and dryer vent cleaning. My house is 11 years old. I figured, $49 is not much. I appreciate your tips on not getting talked into any additional service, not to use solvents to clean, the certification information and before and after pictures. Very useful and I’ll be sure that all I spend is the $49 for the voucher.
Furnace Circuit Board -- The furnace circuit board controls a variety of functions. It not only handles the regular operation of the furnace, it also monitors the furnace's various safety circuits. Over time, vibrations from the furnace can weaken solder point and cause them to separate. Dirt and debris can cause short-circuits that damage the board. Failure of the circuit board can cause a variety of effects ranging from the fan not turning on to the complete shutdown of the furnace.

For more than 60 years Stanley Steemer has been perfecting our hot water extraction method to clean carpet with unparalleled results. Take control of the environment in your home and enjoy a cleaner, healthier living space for your family. Every carpet cleaning is Certified to remove an average of 94% of common household allergens. We remove the dirt you can see and the allergens you can't. 

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.


No matter where you bought your air conditioning system, we can repair it. We have years of experience working with all the best central air conditioner brands such as Kenmore, Carrier. Trane, Goodman, and Rheem. As a result, you can rest assured we’re familiar with your air conditioning system and we have the parts you need to complete a successful air conditioner repair.
The number of years an HVAC system lasts depend on the type and brand of components that make up your system. The lifespan of an air conditioner averages between 15 and 20 years. The life expectancy of a tankless water heater is approximately 20 years, while a storage water heater is closer to 10-15 years. Ducts may need replacing within 10-15 years. Your equipment will have a longer life if you have regular tuneups and maintenance to keep everything in good working order. If you’re having repair problems and your HVAC system is over 10 years old, it’s a good time to consider the costs and benefits of repairing vs. replacing. Energystar.gov provides the following tips to help you decide whether to repair or replace:
On the other hand, if a service provider fails to follow proper duct cleaning procedures, duct cleaning can cause indoor air problems. For example, an inadequate vacuum collection system can release more dust, dirt and other contaminants than if you had left the ducts alone. A careless or inadequately trained service provider can damage your ducts or heating and cooling system, possibly increasing your heating and air conditioning costs or forcing you to undertake difficult and costly repairs or replacements.
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.
DIY: Most DIY installations go smoothly. The major brands have compatibility checkers to see which of their models will work with the wiring your old thermostat is using. Potential problems involve the need for a C-wire, or common wire, when the existing bundle doesn’t include one. There are solutions discussed in our Thermostat Buying Guide, linked to below.
Duct cleaning is a complete scam, I was a “duct cleaning technician” for a whole week before I was fired for not upselling elderly widowed women $2000 extra for “toxic mold remediation” when their ducts were spotless to begin with. The last two days I was employed there I worked as a “helper” alongside a technician thats been with the company 7 years. He scammed every customer on mold and would at times get as much as $2500 extra for treating “toxic mold” in a typical 3 bedroom house in the suburbs. Wait…it gets even better, the “Biocide” the company used was simply a cheap $4.99 per gallon bought at Home Depot air freshener with no anti-microbial properties that was fogged into the HVAC system for 5 minutes, maybe using 1/2 cup of the stuff. In order to provide the customer with evidence of “mold infestation” the technician would be given bogus mold tests that always resulted in “toxic spores present” regardless if you swabbed the actual duct or nothing at all. Not to mention the actual duct cleaning job (typically $400) did basically nothing and the homeowner could’ve done a better job with a shopvac
I own an HVAC company. Dirt in your ducts stays there and hurts no one. It is like dirt on the ground outside. This industry was infiltrated by a bunch of money grubbing low lifes years ago. As a credible company, we do not clean air ducts. Some who were credible probably signed on not knowing what else to do or to try to make a buck another way. These companies, because they also do HVAC work not only rip off private homeowners, they are ripping off legitimate HVAC company's customers and the integrity of what can and should as a rule be a great service industry. Some probably have gotten into this to simply offer what competitors who were ripping off their customers were offering. Anyone cleaning ducts is in my opinion raising a big red flag that they cannot and should not be trusted. Political pressure from NADCA, advertising dollars, manufacturers and marketers of duct cleaning equipment, and intense competition for the customers is the only reason the government and adverstising companies have not run them out of business and that this cancer perpetuates itself.

There is much more to air conditioning than AC installation in Fort Smith, AR then just maintenance and repairs. A variety of other services is required throughout the lifespan of your cooling unit. We are the professional team capable of completing them all. Replacements, troubleshooting, indoor air management, these are all part of our repertoire.


Knowing what you should be paying for your HVAC equipment and installation is essential to getting a fair deal. Most HVAC prices aren’t advertised. Contractor strategy is to get a salesperson into your home to sell you on a package of equipment, accessories and installation. This makes comparing systems difficult, and some sales pressure might be applied.
DIY: Most DIY installations go smoothly. The major brands have compatibility checkers to see which of their models will work with the wiring your old thermostat is using. Potential problems involve the need for a C-wire, or common wire, when the existing bundle doesn’t include one. There are solutions discussed in our Thermostat Buying Guide, linked to below.

I call to follow up at the end of the next day and she said that she has not been able to get in touch with the owner.  By this time, I am starting to get frustrated because I am starting to get the run around.  I question her if I am even on the schedule or if they attempted to schedule a crane.  She says they are extremely busy and that she does not know.  So I say, basically I have waited over 2 weeks and you have not put me on the schedule and I am at the end of the install line.  No answer.  I tell her to talk to her boss and find out what is happening, and I will think about what direction I want to move in at this point.  
An AC contactor is a $25 mechanical relay that uses low-voltage power from the thermostat to switch 220-volt high-amperage current to the compressor and condenser fan. AC contactors can wear out and are at the top of the list of common air conditioning service failures. Even if your AC contactor is working, it pays to replace it every five years or so. Unscrew the old AC contactor before removing the wires. Then move the wires to the new unit (Photo 6).
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