Duct cleaning has never been shown to actually prevent health problems. Neither do studies conclusively demonstrate that particle (e.g., dust) levels in homes increase because of dirty air ducts or go down after cleaning. This is because much of the dirt that may accumulate inside air ducts adheres to duct surfaces and does not necessarily enter the living space. It is important to keep in mind that dirty air ducts are only one of many possible sources of particles that are present in homes. Pollutants that enter the home both from outdoors and indoor activities such as cooking, cleaning, smoking, or just moving around can cause greater exposure to contaminants than dirty air ducts. Moreover, there is no evidence that a light amount of household dust or other particulate matter in air ducts poses any risk to health.
We bought 2 top of the line Lennox HAC for $29,000 less about $3,500 rebates, thinking they would at least last 10 years. Well, after 6 years, the system leaked. We are paying $1,700 to fix that leak. We thought at least it is still under warranty - yes BUT - the warranty covered $15 & the rest we were up for ,even though they advertise 10 year warranty. We are trying to sell & move out of high cost southern Calif & have looked at 20+ places in Arizona. Most of the houses we looked at were built from 1998 to 2005. We asked if the HAC was original & in most case it was - even though the highs were 115 to 120 & the lows 90F - versus where we live the highs run 85 to 95 & the lows are in the 60s. I asked the repairman WHY ours went out at 6 years. He replied that they just do not build them the same anymore. In Arizona, I did not see any Lennox - mostly Trane or Carrier. We had Fujistu in Australia which were fantastic - nothing went wrong in the 9 years we had them. Also, they had full induction motors not like the energy consuming 2 stage motors in Lennox. Maybe the Japanese built Fujusita still builds quality & the warranty is meaningful?
A dehumidifier is an air-conditioner-like device that controls the humidity of a room or building. It is often employed in basements which have a higher relative humidity because of their lower temperature (and propensity for damp floors and walls). In food retailing establishments, large open chiller cabinets are highly effective at dehumidifying the internal air. Conversely, a humidifier increases the humidity of a building.
As a homeowner and an owner of rental property I can tell you that the air ducts sometimes need to be cleaned. If you have had pets or anyone smoking in your home (even a visitor) for any length of time, having the ducts cleaned is really good idea. I had a tenant who did not smoke, but got married to a smoker more than year after moving in. When I realized someone was smoking I had them move out, but the smell was awful. I had the ducts cleaned and sanitized (it was a bit extra). The ducts were shiny like new afterwards. I left the windows open for a few days and we cleaned the place super clean and then replaced the carpets. The duct cleaning was worth every penny because the house looked, smelled, and felt new afterward. I plan to have my own house ducts cleaned again this year as we have two cats. We had them cleaned about 12 years ago and they found building materials in the ducts! If you move into a house that has never had them cleaned, it is good to do it. If you have allergies, clean the ducts to see if it helps. You never know what is in your ducts if you have never had them cleaned.
I replaced all the ducts but the trunks in my 1969 home when I replaced the horizontal furnace under the house with a gas pack. I got advice from a friend who was an HVAC contractor. I was surprised to find the trunks and other ducts very clean. I replaced the individual runs with flex primarily for the insulation. I wrapped the trunks with insulation also.
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.
It seems all the average costs for a complete heating and cooling system replacement I've found on websites are usually at least 1/4 less, mostly half lower, then quotes I've gotten from companies. The worst quote I got was from One Hour Heating & Air Conditioning (the company with the Mike Rowe commercials), for over $15,000! I finally settled on a Carrier dealer, for $10,700 & I'll get $950 of that back in energy co rebates eventually. The company I went with's basic system would have been around $8800 (the only one that sorta matched up with web avg cost). They did all the correct planning as far as I could see, not like One Hour, who just showed me a price guide for the same size units already in place. And they do all the rebate paperwork and submit it to the energy co, One Hour never even mentioned possible rebates! Plus Carrier gets above avg reviews. I would have greatly liked a price under 9 grand, but this company got me 0% APR financing, so at least nothing out of pocket. My advice is stay away from national chains, and shop around with local area companies. Of course, One Hour says local companies will fold before you need warranty service lol. For their cost, there should be a technician living in his work van outside my house hahaha.
How exactly do you expect to kill or remove mold without it ? You can’t even clean your hvac systems coils without moisture of some type ,if you use a steam cleaner you can literally clean the whole system minus the electronics . You should do more research and possibly talk to people who do the work before posting , but don’t listen to me i only have a class A contractor license ,epa license , install /repair hvacs , rent and flip houses for a living .
My 48 yr old house (mine for the last 4 yrs) has considerable dust in the return plenum (fiber duct). I’m remodeling and recently re-sealed the return plenum AND the site-fabbed transition built when the new unit was installed, 2013. The return was leaky no doubt drawing musty, dusty air from the crawl space due to the Red-Neck fab & seal job! Pitiful craftsmanship! It took me 7 hours to fix the new transition piece. Anyway, the dust in the house is the same “color” as whats in the return duct and I’m getting way too much & too often in the house. I’ve also cleaned my coils, which were not that dirty.
Demand controlled kitchen ventilation (DCKV) is a building controls approach of controlling the volume of kitchen exhaust and supply air in response to the actual cooking loads in a commercial kitchen. Traditional commercial kitchen ventilation systems operate at 100% fan speed independent of the volume of cooking activity and DCKV technology changes that to provide significant fan energy and conditioned air savings. By deploying smart sensing technology, both the exhaust and supply fans can be controlled to capitalize on the affinity laws for motor energy savings, reduce makeup air heating and cooling energy, increasing safety and reducing ambient kitchen noise levels.[29]
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.

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.


I have a white gritty dust throughout my whole house. Dust and it comes right back. We have central air. In 2013 had all the air conditioning tubing in the attic replaced. Old ones were completely clean. Why?? Thought dust would be in there. Put everything in plastic containers. Furniture everything is always covered with this. Problem is always there year round. Furnace people said it is not coming from furnace. We built house in 1971. Only started with this @ 19 years ago. Thinking when air conditioning went in. We cough all the time and sneeze. I do not have friends come here because I hate how dirty my house looks.
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.
Air duct cleaning service providers may tell you that they need to apply chemical biocide to the inside of your ducts as a means to kill bacteria (germs) and fungi (mold) and prevent future biological growth. They may also propose the application of a "sealant" to prevent dust and dirt particles from being released into the air or to seal air leaks. You should fully understand the pros and cons of permitting application of chemical biocides or sealants. While the targeted use of chemical biocides and sealants may be appropriate under specific circumstances, research has not demonstrated their effectiveness in duct cleaning or their potential adverse health effects. No chemical biocides are currently registered by EPA for use in internally-insulated air duct systems (see Should chemical biocides be applied to the inside of air ducts?).
We installed a TRANE XL18 HVAC with a TRANE HV80 furnace 16 years ago and it still works great in Tucson, AZ.  We inquired into a replacement for the future since the R-22 refrigerant will be off market at the end of this year.  Our maintenance folks want to sell me a new system anyway (even though the TRANE works great).  We are considering the BOSCH Inverter heat pump as a lower cost option down the road.  Watch out for the tricky salesmen trying to sell beer at champagne prices though. Get estimates on whether you need to replace your current system and how much it could cost.  And if they are factory certified.
No one has addressed mfg homes and doesn't seem any of the comments are from people in So CA which of course does make a difference as my dust comes from the outside not from the vents. My windows are open pretty much 365 days a year. Secondly mfg homes don't have basements or attics I keep mine clean with my vacuum as they are only about 2 ft deep. I purchased my home 10 yrs ago and it is a high end home but have never had a problem. I clean my furnace filter about twice a month as I have cats and most everything in there is cat fur. I am not saying they don't ever need to be cleaned but I am questioning mfg homes, I also clean my own filters in my AC unit outside as the HVAC guy told me too he QUATITY they would sell. I use this same company every year now for my tune up and inspection which takes them about 10 minutes. Not a bad return for them and I don't mind the $79 fee. If anyone has more info than this on mfg homes please let me know!
CIBSE publishes several guides to HVAC design relevant to the UK market, and also the Republic of Ireland, Australia, New Zealand and Hong Kong. These guides include various recommended design criteria and standards, some of which are cited within the UK building regulations, and therefore form a legislative requirement for major building services works. The main guides are:

Filtration systems -- A second-stage filter is sometimes inserted & used to remove particulates such as pets, smoking or cooking, as well as other odors, gases, and VOCs (volatile organic compounds). A HEPA filter is also available to remove spores, pollens, bacteria and lung-damaging particles. There are also systems that use ultraviolet (UV) light to protect against bacteria and germs.
You can install the greatest HVAC system ever built, but if your house is not insulated well, it's only going to end up costing you more money. Older homes may have fiberglass insulation that has broken down due to pests, moisture, or improper installation. Spray foam insulation can be damaged by careless repair or modification work or can be improperly installed. If your insulation in compromised, your attempts to save money and be comfortable will be in vain.
Interesting. Giuliano Cuete and Carlo Olcese have the exact same post about pretenders and being NADCA certified, word for word. So how do you become NADCA certified? And does that mean you are not a scam artist or a "blow and do" ripoff? hmmm, interesting. The EPA says that under normal conditions, a properly maintained system should NEVER need it's ducts cleaned.
We installed a TRANE XL18 HVAC with a TRANE HV80 furnace 16 years ago and it still works great in Tucson, AZ.  We inquired into a replacement for the future since the R-22 refrigerant will be off market at the end of this year.  Our maintenance folks want to sell me a new system anyway (even though the TRANE works great).  We are considering the BOSCH Inverter heat pump as a lower cost option down the road.  Watch out for the tricky salesmen trying to sell beer at champagne prices though. Get estimates on whether you need to replace your current system and how much it could cost.  And if they are factory certified.
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).
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.
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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