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.
A year and a half ago (fall of 2015) we replaced the furnace and air conditioner. From what we could determine this was the third forced air furnace and second air conditioner unit for the house. As part of the installation, we changed out the two 6″ ducts feeding the second floor with 8″ ducts. The idea was to get more cold air to the second floor in the summer. It worked and for the first time the second floor and first floor temperatures were the same when the air conditioner was running. Of course, to make the system work I close down upstairs duct damper doors in the winter and open them up in the summer.
I have been a plumbing/gas/hvac tech for 19 years, before that I installed ductwork in commercial buildings and office towers. As the article states, unless you have undergone some type of extensive reno, or ducts have become contaminated, paying for cleaning is pointless. Its one thing if you have a 30 year old home that has never had a duct cleaning and you can actually see mounds of dust built up , especially in the return side, then go for it. Keep in mind that most duct cleaning companies will only get 80% of the dust , or less at best. Keep in mind that most of the dust in your home is lint from clothes and linens, and skin cells from you and your pets and is constantly being generated. Dust that builds up in ductwork , generally stays in the ductwork. The power of suggestion, scare tactics, up sell!!!
I purchased a Groupon for cleaning of unlimited air ducts and one return vent for $39. I should have checked into their hours first because they only offer services during normal business hours. So, with no evenings or weekends available you have to take time off work. I asked Groupon for a refund when I realized this and they refused because it wasn’t within the three day window. Then they didn’t even show up or call for the appointment. I called them after they were an hour late and they were going to call the local dispatch office and have them call me back within 15 minutes. I did not receive that call. I called again and was told I would get a call back from a manager. That didn’t happen either. So I asked Groupon for a refund again and they gave me Groupon bucks. When the survey came asking if I was satisfied with the Groupon customer service I said no, I want real money. I got my real refund the next day. Seems to me Groupon should stop dealing with these companies.

The use of furnaces, space heaters, and boilers as a method of indoor heating could result in incomplete combustion and the emission of carbon monoxide, nitrogen oxides, formaldehyde, volatile organic compounds, and other combustion byproducts. Incomplete combustion occurs when there is insufficient oxygen; the inputs are fuels containing various contaminants and the outputs are harmful byproducts, most dangerously carbon monoxide, which is a tasteless and odorless gas with serious adverse health effects.[14]


The liquid refrigerant is returned to another heat exchanger where it is allowed to evaporate, hence the heat exchanger is often called an evaporating coil or evaporator. As the liquid refrigerant evaporates it absorbs energy (heat) from the inside air, returns to the compressor, and repeats the cycle. In the process, heat is absorbed from indoors and transferred outdoors, resulting in cooling of the building.
The amount of debris or mold present in your system could certainly ratchet up the overall price. The cost of mildew removal is around $0.07-0.08 per square foot, on top of your initial cost, according to Blue Book. Removing these elements involves added time, special equipment and even special chemicals. In fact, you may be referred to a specialist if mildew and mold is too severe.
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.
Air conditioning and refrigeration are provided through the removal of heat. Heat can be removed through radiation, convection, or conduction. Refrigeration conduction media such as water, air, ice, and chemicals are referred to as refrigerants. A refrigerant is employed either in a heat pump system in which a compressor is used to drive thermodynamic refrigeration cycle, or in a free cooling system which uses pumps to circulate a cool refrigerant (typically water or a glycol mix).

If you are using existing ducting, it will have to be inspected. Proper ducting loses around 2% to 5% of your energy. Old, leaking ducts can lose 50% or more. A contractor will need to have the ducts inspected and replace any parts ahead of time. If you are changing the size of your HVAC system because of significant changes to your home, you might need to replace the ductwork regardless.
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.

 The A/C System Cleaning and restoration industry has become a very lucrative bait and switch industry that many Carpet cleaning companies, Maid services, as well as plumbing or handyman service companies are adding on to there services. These add-ons are not fully certified, trained or even have any experience in the HVAC industry. These companies are the reason prices and quality of work are all over the place. If you are looking to make a smart decision for your home a professional Duct Cleaning service will protect you for 5-7 years. This info comes from NADCA (National Air Duct Cleaning Association) which is the closest thing to a license we have for duct cleaning. They have a great site that explains this process and pricing much more in depth and factual than what has been written here. This organization is working very hard to get these bad companies exposed and out of this industry. So in saying that do your research! Green Duct Decontamination is a certified company with certified technicians that take this work very seriously. We can not have these low rated unprofessional companies paste a bad name for an entire industry. Stay away from anything under 250$ for a full duct clean this is not feasible, go look at NADCA.com and you will understand why and what these companies are doing to rob you of your dollar.


My best advice has always been that a proper duct cleaning is a valuable investment when moving into a home (new or old), after major renovations and if the ducts have never been cleaned before. It is unlikely that there will be increased air flow, as finding major blockage is unusual, but this will eliminate this as a possible concern if there are air flow concerns. It is also true that the "dust" that is cleared out will most likely never have been distributed through the house unless there has been some work done on the ducts. What is cleared out will be pet hair, toys, clothes, construction material, and biological material (small carcasses and/or feces). Once a proper cleaning is done a follow-up is rarely necessary, but up to the home owners discression.

You should be aware that although a substance may look like mold, a positive determination of whether it is mold or not can be made only by an expert and may require laboratory analysis for final confirmation. For about $50, some microbiology laboratories can tell you whether a sample sent to them on a clear strip of sticky household tape is mold or simply a substance that resembles it.


You can adjust for seasons: During the summer, you can have the air conditioner stay off during the cooler morning hours and start cooling the house as everyone gets up and starts moving around. During the winter, you can have your heater stay off while you are away at work and turn on about a half hour or so before you get home so that you are coming home to a nice, warm house.
Internal insulation provides better acoustical (noise) control. Flexible duct is very low cost. These products are engineered specifically for use in ducts or as ducts themselves, and are tested in accordance with standards established by Underwriters Laboratories (UL), the American Society for Testing and Materials (ASTM), and the National Fire Protection Association (NFPA). Many insulated duct systems have operated for years without supporting significant mold growth. Keeping them reasonably clean and dry is generally adequate. However, there is substantial debate about whether porous insulation materials (e.g., fiber glass) are more prone to microbial contamination than bare sheet metal ducts. If enough dirt and moisture are permitted to enter the duct system, there may be no significant difference in the rate or extent of microbial growth in internally lined or bare sheet metal ducts. However, treatment of mold contamination on bare sheet metal is much easier. Cleaning and treatment with an EPA-registered biocide are possible. Once fiberglass duct liner is contaminated with mold, cleaning is not sufficient to prevent re-growth and there are no EPA-registered biocides for the treatment of porous duct materials. EPA, NADCA and NAIMA all recommend the replacement of wet or moldy fiber glass duct material.
A BTU is the amount of energy required to heat or cool one pound of water by one degree Fahrenheit. So a 1-ton air conditioner can cool 12,000 pounds of water by one degree every hour. That’s all it means, so don’t let yourself be lost in jargon! How this affects your HVAC installation cost is that the larger your house is, the more tons will be required to heat and cool it.
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.
Wiring up the thermostat is usually pretty straightforward if an old one is being replaced. If a thermostat is being put in where one had never been before, that could involve running new wiring. The placement of the thermostat is also important so that its sensors can get an accurate reading of the temperature. A thermostat that is blocked by a bookcase or other large furniture will not get a good reading and will not perform efficiently.
If you’re anything like most of our readers, you’ve spent hours online researching HVAC information in preparation for replacing your old heater or air conditioner. I’m the same way; it’s a big investment! You may want to consider saving yourself some time and money by getting an HVAC-Facts Report from this online HVAC installation cost calculator.  Take a look:
Your HVAC unit and air ducts deliver heated or cooled air throughout your home year-in and year-out. The air your HVAC unit produces travels through your ductwork and heats or cools your home via the air vents in each room. The dust and other particles in your home’s air are known as particulate matter, which the EPA defines as "a complex mixture of extremely small particles and liquid droplets." The EPA also notes that "particle pollution is made up of a number of components, including acids (such as nitrates and sulfates), organic chemicals, metals, and soil or dust particles." Having clean air ducts means fewer of these particles moving through your home. If you remove your furnace filter and hold it up to the light, you can probably see several hundred of these minuscule particles floating in the air. 

From Day 1, Alberto walked us through the process, and present us with a variety of options based our budget for the project. His customer service is the best as he did not oversell any services and did not nudge us towards buying a unit that would stretch our budget. On installation day, HVAC Services sent out a crew of 6-7 guys, all of whom were very polite and kept their work areas clean, and installed the whole system the same day.
Bigger is not necessarily better when it comes to HVAC systems, and smaller isn't always more efficient. If you have too small of a system, your system will be running constantly as it tries to keep up with the temperature. If you have too large of a system, it won't run long enough to keep up with the humidity. In order to handle both temperature and humidity efficiently, an HVAC system should run for around 30 minutes at a time. If your system is staying on too long or shutting off after only around 10 minutes, you are not getting efficient performance.
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.”
Asbestos removal tip.  Don’t trust any HVAC installation company that says that they will remove asbestos for you. They will do either one of two things: remove it and do a horrible job because they don’t know how (an illegal act in California, finable by up to $250,000), or they will say they did and never actually do it, which is dangerous to your health. Any HVAC contractor worth their weight will know not to touch it. Call an asbestos abatement company – it should cost around $500-$1,000, and your HVAC installation company will come in right after them and do the installation to decrease cost and inconvenience.
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.
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.
I took off stars for two reasons. Minus one star for issues trying to use the $50 for $25 voucher I purchased through Yelp. Although there was no minimum stipulated, the office wouldn't take it for the initial $59 diagnostic fee. If I used the 10% off First service that they offer, then they won't let me use the voucher on the actual repair bill.  I was stuck with paying the full $59 diagnostic fee. 

SEER is useful for comparing one model to another much in the same way that a car's calculate MPG is useful. It's not an accurate prediction of exactly how efficient the system is, but it can tell you which one is more efficient. Also, since SEER is based on a "cooling season", what region you live in will determine how long or short your cooling season is.
The short answer is yes, duct cleaning, done right by a reputable company will help with the smell. It is likely though the smell is coming from another source, ie the crawl space. It could also be that another rodent is dead in the duct work. A visual inspection would be in order to check for any breach in the duct system. A duct pressure test would be able to tell you how much air is leaking from the system over all. A hole large enough for an animal to enter would loses a great deal of air, over 300 CFM. It would be worth looking into having this test done and it should cost around $200. Cleaning the air handler and evaporator coil will greatly improve the performance of the air conditioner. Dirt and dust on the evaporator acts as insulation and reduces the amount of cooling done be the coil. Any quality duct cleaning should include cleaning the air handler and coil, and the tech should allow you to watch him perform the work as it is done.
I've been in business in Florida for 25 years and purchased a $12,000 duct cleaning system 4 years ago. In the last four years I've cleaned 5 duct systems charging around $400 each. Not a very good return on investment. What I have been doing most the time is I get a call by someone panicked because they called some low priced company to inspect their system and were told they have dangerous black mold. Then they call me to have a look. Most the time they don't have mold, ducts look very clean. However the coils are dirty and the inside of the air handler cabinet needs cleaning. Keep in mind not every system can handle supper high efficiency filters! These filters can block air flow quite a bit right out of the package. Many older systems can't handle pleated filters due to increased static pressure. "Back rooms with low air flow". I have taken many hours of classroom study on indoor air quality. Never got any certification because I don't want to pay another organization dues yearly. I think the problem with duct / system cleaning is most people are suckers for low priced scams that are rip- offs . People call me all the time and ask how much? When I tell them average $400 they hang up. I know I do the job correctly and honestly, and they are going to get racked over the coals by the scam artists by calling $79 whole house duct cleaning guys. People need to check internet, angies list and BBB reviews. But keep in mind even reviews need to be sifted through your rational person filter.
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.
Some of these components can be repaired or replaced by the homeowner, such as filters, fuses, and clogged up drain lines. Coils, compressors and the other components are best left to a professional. In some cases, you may have a system that is so old that parts are no longer available or else they aren't up to code. In this case you will have to consider replacing the entire system.
You've probably noticed many appliances boasting an Energy Star Certification. What this means is that manufacturer voluntarily built the product to help reduce greenhouse gases and meet non-regulatory guidelines offered by the Environmental Protection Agency. To earn an Energy Star rating, a product or system must be tested by a third party that has been recognized by the EPA for meeting their testing qualifications.

I hired duct cleaning company out of "Service Magic" website. I did not realize the name of his company was Duck cleaning of Central Florida...that should have given me a hint.. The guy did a very poor, incomplete job, and ruined a closet full of clothes when he sprayed up to clean a vent instead of taking it down and cleaning it outside. He left me with more than 1/2 dirty vents and ducts, did not do the air handler in the garage and failed to fog the system. He spent 6 useless hours at my residence and now his insurance is denying coverage..very disappointed in Service Magic....
The heat pump gained popularity in the 1950s in Japan and the United States.[13] Heat pumps can extract heat from various sources, such as environmental air, exhaust air from a building, or from the ground. Heat pumps transfer heat from outside the structure into the air inside. Initially, heat pump HVAC systems were only used in moderate climates, but with improvements in low temperature operation and reduced loads due to more efficient homes, they are increasing in popularity in cooler climates.
Installation: Replacement is quite easy, especially when an old refrigerant line set can be used. If the set is worn, it’s much better to pay the extra $400-$600 to replace it rather than risking it leaking later. When your AC loses refrigerant, you lose your cool air and the compressor is at risk of failing. A new installation means installing a coil in your furnace or air handler, running the line set between it and the coil in the condensing unit and adding refrigerant, if needed. Most ACs come pre-charged for 20-30 feet of line. If the line set is longer, a small amount of refrigerant is added.
Central home air conditioner service systems consist of two major components: a condensing unit that sits outside your house, and the evaporator coil (often referred to as an A-coil) that sits in the plenum of your furnace or air handler. The refrigerant in the A-coil picks up the heat from your home and moves it to the outdoor condensing unit. The condensing unit fan blows outside air through the condensing coil to remove the heat. The condensing unit houses the three parts replaceable by a DIYer: the AC contactor, the start/run capacitor(s) and the condenser fan motor. The condensing unit also houses the compressor, but only a pro can replace that. The A-coil has no parts that can be serviced by a DIYer.
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