I’m really not convinced that duct cleaning is of any value. My roommate wanted the ducts cleaned so he called some company. My scam senses is already tingling. They came in with a big negative pressure fan. Did some blowing and sucking in different vents. Then they tried to upsell a full system cleaning. They wanted to pull the blower and clean the heat transfer box at $700 per heater unit. I have a big house so we have two units. They also tried to sell us some “custom” $250.00 Air Lifetime air filters. At that point I pulled the BS get the hell out bell. After paying $520.00 for just the cleaning, I paid the bill and sent them on their way. I replaced the existing filter with the good old and cheap paper filters at $10.00 each. Duct cleaning… I’m not Impressed.
Just had my air ducts cleaned. They used a high pressure air hose in all the heat ducts and cold air returns. He showed me the stuff that came out, the reason for the duct cleaning was the fact that I had a problem. With rodents. There was quite a few mummified rats and mice, and he said I wouldn’t have to have them done again unless I incur another problem or have renovations done. Cost me 345.00 for a 2 storey large old home. Not a bad price as I had them done when I moved in 28 years ago and it cost me 500.00. Lots of dog hair, toys, balls and assorted goodies came out as well. Took them 2 hours. I did have sanitizer put in the ducts because of the dead rodents.
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.
I had someone out to clean my ducts last weekend. He took a blue bag up in my attic. He came back down in just a few minutes and said I had mold and he even showed me a picture of something saying it was mold but I couldn’t really tell. I refused his service to take care of the mold. He went back up in the attic for a little while and then came down. I never heard any sounds that he was actually up there doing anything. How do I know if he actually cleaned the air ducts?
Humidifiers/Dehumidifiers: Humidifiers add needed moisture to the air in winter and very dry climates. Dehumidifiers remove dampness any time of the year. Central air conditioners dehumidify too, but in very humid climates, you might want to remove humidity without also cooling the air. You have a good range of options for both of these HVAC accessories. Whole-house humidifiers cost $350 to $800 installed, while dehumidifiers are $1,250 to $2,000 or slightly more.
I am 79 years old, bought a condo & spent a lot of money on it. this winter my first bill was 450.00. had my furnace checked out, which is on the roof. it was old rusted out & leeking oil. i talked to owner & had new unit installed. they came out to clean ducks & they were split & worn out. there is no crawl space because theres a unit above me. my real estate lady or this company will not help me fix this problem.
Reinstall the access panel and disconnect block. Turn on the circuit breaker and furnace switch. Then set the thermostat to a lower temperature and wait for the AC to start (see “Be Patient at Startup,” below). The compressor should run and the condenser fan should spin. If the compressor starts but the fan doesn't, the fan motor is most likely shot. Shut off the power and remove the screws around the condenser cover. Lift the cover and remove the fan blade and motor (Photo 7). Reinstall the blade and secure the cover. Then repower the unit and see if the fan starts. If it doesn't, you've given it your best shot—it's time to call a pro.
Many disconnect blocks contain two cartridge fuses. Check them before you proceed with repairs (Photo 3). A blown fuse is a sign of a failing part inside the condensing unit. So don't just replace it and think you've solved the problem. Instead, replace the parts we show here. Then install new fuses and fire up the unit. If it blows again, call a pro—you've got more serious issues.
With today’s consistently rising energy costs, improperly sealed windows, ductwork, and poor insulation can pose serious problems for many home and business owners in Arkansas. Wilson's Heating & Air Conditioning provides complete HVAC system servicing including sales, installation, maintenance and repair, and offers numerous practical solutions that will reduce your energy costs.

Is there a such thing as a PQ-15 valve? No…but how do we know? And oh, by the way, there are only two types of line-sets: 3/4 inch, and 7/8 inch. All modern equipment runs on a 7/8 inch line-set, so the only time they’ll have to change something is if you have antiquated 3/4 inch line-set from the 60’s or 70’s. I’m digressing though…the point is that they can easily prey on uninformed consumers…like you, baby bird! Don’t worry though…you’ll be flying by the end of this article.


Rheem's RRNL features a scroll compressor with fewer moving parts and less noise than traditional reciprocating compressors. A louvered compressor compartment protects the compressor from the elements and from debris that can shorten the life of the compressor. The Classic series continues to be one of their best sellers, with the addition of the Comfort Alert diagnostics module integrated to assist technicians in the event your system needs repair. 2-5 tons, 13 SEER, 80% AFUE.

PickHVAC Tips: Electricity resistance heat is the most expensive heating type. You don’t want one of these unless you’re heating less than 30 days per year. The upfront cost of an electric furnace is much lower than the cost of a gas furnace. However, operating costs are two to three times higher. If winters are cold where you live, you’ll waste your upfront cost savings in just a few years of high electric bills.
I agree, if you replace (or wash depending on type) your air filters regularly AND vaccum, then you probably don't need the ducts or air coils cleaned. However, if you purchase a pre-owned home, and the previous owners did not regularly change the air filter or vaccum the home, then duct cleaning is worth the expense especially if you are sensitive to allergens. Especially if the previous owners had pets.
Equipment used to clean ducts varies widely. The cheaper the equipment used the more you are just wasting money. This is why it's typically not worth doing. In some situations it may be beneficial, but only after determining and investigating the duct system. This should be done by a licensed HVAC contractor and not a duct cleaner that typically do not hold and HVAC license. (Duct cleaners aren't required to be licensed in HVAC in many areas.)

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]
Despite such anecdotal experiences, there's no scientific evidence that regular residential air duct cleaning improves air quality, according to a 1997 brochure published by the Environmental Protection Agency. Laureen Burton, senior scientist in the EPA Indoor Environments Division, says that while the document is nearly two decades old, the science hasn't changed and the agency stands by its recommendations.
Ok what you said is true but in most cases ducts are in a duct flex format, and knowing that the dust in people's flex duct is just surface dust, any real debris that are in the duct itself will result in very little to no air flow which will keep your unit from performing properly, but if it is true allergy reasons then replacing your duct system is better for overall better air quality, plus if you do pay attention to the warranty on flexible duct is that it only has a 10 year warranty and typically only lasts for 20 years so do your research before having a duct cleaning, and to add one more thing if your duct work is completely metal and you can't see visible insulation then your duct on the inside has insulation inside of it, if you replace that with duct work that is clean metal on the inside and wrapped with insulation on the outside then it will further reduce the air bourne fiberglass and dust.
An example of a geothermal heat pump that uses a body of water as the heat sink, is the system used by the Trump International Hotel and Tower in Chicago, Illinois. This building is situated on the Chicago River, and uses cold river water by pumping it into a recirculating cooling system, where heat exchangers transfer heat from the building into the water, and then the now-warmed water is pumped back into the Chicago River.[24]
The key to the continued and efficient operation of your heating and cooling system is periodic maintenance. Cleaning the air duct vent system, and servicing you heating and cooling equipment will keep the system operating at its peak performance. Air ducts are cleaned for two reasons. One: to prevent debris from entering furnace and air conditioning components. Two: to prevent debris from cycling through the home. The air duct cleaning contractor needs to employ cleaning methods which successfully removes debris, and ensures that debris does not enter the occupied space. Most contractors can verify the results of the cleaning through video or pictures.

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.
Tip – Be careful with change-outs. Ductwork deteriorates and sometimes has to be replaced.  It is only if the ductwork is in fantastic condition that you should get a change-out without ductwork (Remember – the ductwork has already been there for 15-20 years, and now it will be there another 15-20…it has to be in good shape). However, many HVAC installation companies like to push change-outs because the ductwork is the most time consuming part of the job, and a change-out is quick, easy money. Realize that it’s only about 15-20% of the jobs that qualify for a change-out, so be careful.
It's always changing: Some newer thermostats take advantage of wireless technology. You can adjust your thermostat remotely so that if you leave and forget to adjust it, or if you are going to be home later than you thought, you can adjust it via your smartphone. Some can even give you reports on how efficient your system is performing based on usage. These are very efficient models, but they are also very expensive with some costing over $250.00.
Had duct cleaned (apartment) however, dust is still settling throughout the apartment. Contractor said no other cleaning necessary until two (2) years. Is there a time period before dust no longer settles prior to that time? Should the vendor had worn a mask? He did not cover his face the vents and dust was blown throughout the apartment (had family help with the cleanup). I had to leave when they left because I have asthma and I couldn’t breathe without coughing. Please help!
There is a lot of good, general information in the article. As with anything, the homeowner should do their due diligence in getting enough information to make an educated decision. Should duct-work be cleaned? YES! Does it need to be cleaned annually or even every second or third year? Not necessarily. It all depends on a bunch of variables. You're right that a well designed and balanced system will deliver the right amount of air flow, but sometimes conditions outside the home/business, make it a necessity to get the ducts cleaned. As for mold? NO filter is going to address a mold issue. If you have mold, you have a moisture issue that needs to be addressed. Also, in my 38 years of experience in the HVAC and sheet metal industries, washable filters are one of the reasons ducts need to be cleaned. They are no where near efficient in cleaning/filtering the air to the level that they should.
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:
The Antimicrobials Information Hotline provides answers to questions concerning current antimicrobial issues (disinfectants, fungicides, others) regulated by the pesticide law, rules and regulations. These cover interpretation laws, rules and regulations, and registration and re-registration of antimicrobial chemicals and products. The Hotline also provide information health & safety issues on registered antimicrobial products, product label and the proper and safe use of these antimicrobial products.
We hope you found this article on a fair HVAC installation cost helpful. In the end, you’ll be alright so don’t worry too much. Do your research on reputable air conditioning contractors in your area, and spend time making sure that you have a company that you can trust – it will cost you less in the long-run, trust me. Take your time, follow the tips above, and you will end up with an HVAC installation cost that is more than reasonable, keeping your family comfortable for years to come. For more on topics like this, see: ASM’s Air Conditioning Blog.
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. 

I am 79 years old, bought a condo & spent a lot of money on it. this winter my first bill was 450.00. had my furnace checked out, which is on the roof. it was old rusted out & leeking oil. i talked to owner & had new unit installed. they came out to clean ducks & they were split & worn out. there is no crawl space because theres a unit above me. my real estate lady or this company will not help me fix this problem.
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.
Compressor -- Compressors are outdoor components in your system. The compressor is the pump that circulates the refrigerants through the air-conditioner. You can hear it when it's running so you'll know if it's working just by listening. If it starts getting louder, your compressor is about to fail. If it makes no sound when it should be on, it has already failed. Compressors fail for a number of reasons. Most often they fail due to strain from another failed part such as the fan motor. Electrical storms can also damage compressors. If the sound from the compressor gets louder or if you see a decrease in performance, you should have your compressor checked. A failed compressor will not heat or cool your house.
Equipment used to clean ducts varies widely. The cheaper the equipment used the more you are just wasting money. This is why it's typically not worth doing. In some situations it may be beneficial, but only after determining and investigating the duct system. This should be done by a licensed HVAC contractor and not a duct cleaner that typically do not hold and HVAC license. (Duct cleaners aren't required to be licensed in HVAC in many areas.)
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.
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.

What you might not know is that the brand you choose is one of the most important factors in determining a fair HVAC installation cost. So, before delving in-depth, let’s take a quick look at the average prices of a new air conditioner and matching coil by brand…keep in mind, these are the average prices (by brand) that contractors pay for your AC equipment, and it is meant to give you a rough guideline until you are closer to buying:
If the one noticeable spot is where the wall [or ceiling or floor] is white.......first.....take a pair of needle nose pliers and bend each louver of the register to a straight outward position [as they all come brand new with a slant to each side]....so the register is shooting all supply air straight outward. If its a round register [in ceiling].....no help there. You also should always burn soy or beeswax candles.
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.  
HVAC System Quality Installation Contractor Checklist -- This checklist identifies all of the steps the contractor has taken for the Energy Star Certification and identifies what work the contractor has done. If the system is later modified, this checklist can help identify what was done to proper Energy Star specifications and what was added later that may not meet the requirements.
HRV/ERV Ventilators: These whole-house ventilators exchange air. They are ideal for homes with what is called a “tight envelope,” homes where house wrap has been applied and airgaps in the attic, around windows, doors and outlets have been sealed. Air in these homes becomes stale and polluted, so exchanging the air is important to IAQ. Heat recovery ventilators (HRV) are designed for cold climates. Energy recovery ventilators (ERV) are best for warm climates.  Your cost for an installed HRV or ERV will range from about $2,000 to more than $5,000 based on its capacity and features.

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.
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:

In the United States, HVAC engineers generally are members of the American Society of Heating, Refrigerating, and Air-Conditioning Engineers (ASHRAE), EPA Universal CFC certified (for installation and service of CFC HVAC devices), or locally engineer certified such as a Special to Chief Boilers License issued by the state or, in some jurisdictions, the city. ASHRAE is an international technical society for all individuals and organizations interested in HVAC. The Society, organized into regions, chapters, and student branches, allows exchange of HVAC knowledge and experiences for the benefit of the field's practitioners and the public. ASHRAE provides many opportunities to participate in the development of new knowledge via, for example, research and its many technical committees. These committees typically meet twice per year at the ASHRAE Annual and Winter Meetings. A popular product show, the AHR Expo, is held in conjunction with each winter meeting. The Society has approximately 50,000 members and has headquarters in Atlanta, Georgia.
i got angies list deal for 109 air duct clenaing, dryer vent cleaning, and furnace inspection, {healthy duct cleaning} i call the company, they arrive on time. did excellent service what ever i purches i got. they give me furnace inspection and the told me that my furnace is very dirty and they offer me to clean that for 250 extra. i paid and i am very happy from this service. i try before 2 diffrent company that i got deal from them as well the just give me estimate and don’t even do the job. so guys don’t spend time if you need deep cleaning just cal this guy the offer free estimate as well.
Lennox, on the other hand, is probably the most expensive unit out there and I can’t stand them.  In our (humble?) experience, they have a horrible logistics chain, making repair parts difficult to come by (sometimes taking weeks), poor customer service, and the parts cost three times as much. That’s not what this article is about, so read more in: Carrier vs. Lennox Furnace Review.
If you’re purchasing from a big-box store, you can expect to pay approximately $120-$1,000 for a window unit. Window units are appealing for their quick setup and relatively low cost, but they can use more energy over time than central air and only cool the room in which they’re installed. The price will vary depending on the type of air conditioner you buy and its cooling capacity. Window units, which require minimal installation, are one of the most affordable options on the market. Portable air conditioners don’t have the cooling power of a window unit, but they do have the perk of being transportable from room to room. Expect to pay between $225 and $800 for a portable air conditioner, on average. The cost of an air conditioning system with coils, condenser and line (not including installation or ductwork) can range from approximately $2,000 to $4,000 or more. If you don’t have (and don’t want to put in) ducts, a ductless mini-split air conditioner is a good option, although pricey up front. Pricing can range from $650 to $4,250 per unit on average; you’ll need one unit for each room in which you want temperature control.
One of the difficulties encountered by many air duct cleaning service companies is that their attention is not really on air duct cleaning. For example, many heating and cooling companies offer duct cleaning as a supplemental service, but of course their primary business is installing and servicing heating and cooling equipment. For these companies, air duct cleaning is not always given the attention it deserves and is often done by less experienced employees whose interest is not in duct cleaning but in repairs and installs. And it is almost always done with inferior air duct cleaning equipment. Still other firms (like carpet cleaners) offer a large variety of services and claim to “do everything.” Because of their lack of focus they may not actually be very good at many, if any, of the services they offer. They cannot simply buy an attachment for their carpet cleaning machine and magically become a great duct cleaner.
I just bought a home, and the sellers clearly never had the air ducts cleaned. This is, unfortunately, typical of their neglect of the home, so I am not surprised. I was cleaning around the wooden floor registers, and I took the registers off. I found nests of some sort...all kinds of really gross stuff!! I am calling now to schedule duct cleaning for my new home. Anyway, it is very easy to check to see if you really need duct cleaning. Remove the floor registers and use a flashlight if necessary to see if there is dust or debris in the ducting. If these look bad, I'd definitely have the system cleaned. I would also do it after a construction project, after installing a new furnace, etc. I have found that once I had my previous system cleaned, it seemed to remain spotless for 3 years. So it seems that if you just change your filters on time (I have an iPhone alert set for every 3 months), the system will stay clean for years. Hope this helps!

As you can see, if we know what the contractor is actually paying for specific equipment, we know what their labor rates are, and we know what they bid the project for, then we can also use some basic algebra (or just let the program do it for us because we’re lazy) to figure out how much of a profit they are making off of us (you) at different bid prices:


I own a small mechanical company. My main work is service and system replacements. I have never been a believer in duct cleaning. The company I worked for before had our duct man come out and do my house. I saw no difference. Preventive maintance is what I recomend. Remove fan and clean, seal fan compartment to prevent dust from being pulled in, filters I install media filters, they are 5″ thick and pleated. I have tested them to make sure static presure was not a issue. Heat exchangers and AC coils need to be cleaned. I will tell you this to do a good cleaning I usually spent 1-2 hrs, When I’m finished I would not have a problem eating my diner on the system. Good filters, clean system and properly tuned up are my recomdation to anyone. I’ve included my email feel free to contact me with any questions. winkcfd@yahoo.com
I’m really not convinced that duct cleaning is of any value. My roommate wanted the ducts cleaned so he called some company. My scam senses is already tingling. They came in with a big negative pressure fan. Did some blowing and sucking in different vents. Then they tried to upsell a full system cleaning. They wanted to pull the blower and clean the heat transfer box at $700 per heater unit. I have a big house so we have two units. They also tried to sell us some “custom” $250.00 Air Lifetime air filters. At that point I pulled the BS get the hell out bell. After paying $520.00 for just the cleaning, I paid the bill and sent them on their way. I replaced the existing filter with the good old and cheap paper filters at $10.00 each. Duct cleaning… I’m not Impressed.
All of you have dentists, you have doctors, you have preachers, you have mechanics. You don’t have to know everything about everything but you have to have people in your life that you can trust. Don’t just open up the phone book and pick a mechanical (HVAC) contractor. Call your friends and family and ask for referrals. There are no black and white (scam or not a scam) answers here.

Our heater went out last Saturday, which was a cold day.  Called a few different places and they were the only ones that called back.  The technician Tony came out and after a little testing said the main control board needed to be replaced.  He quoted us a total of $489 which seemed on the high side but it was cold and we were somewhat desperate, so we agreed and paid a parts deposit.


Hi John, Thanks for reaching out, we would be happy to help you connect with a pro for your project. You can submit a request to our pros here: www.homeadvisor.com, browse a list of pros that serve your area here: http://www.homeadvisor.com/c.html, or send your info to emailus@homeadvisor.com and a project advisor will reach out to assist you. –HASupport
As I type this, I am having my ducts cleaned. About 30 including returns and the furnace. $543.00. I am watching the team do it and can see the clear vacuuming tubing and how dirty it has become. I like the gentleman’s comment on “stick your head in your vacuum and breath”….I get it. The team showed me the machine and it’s filtration system…and they will show me it again after the cleaning. However, like I said before, I am actively seeing the tubing that is clear before they start and how dirty it is once they begin and continue cleaning. Reputable company and not a “fly by night” coupon service. People don’t be so cheap, that is your problem.

Consider what kind of heating and cooling system you want installed for the square footage of your home. Do you want a full system with a thermostat or a specific machine for the summer like a swamp cooler? Do you need a new furnace just for the winter? For any of these projects, the cost will vary depending on the quality, style and machine size you choose. If you have a tight budget, think of going smaller and upgrading over time. For example, if you can't afford to convert your entire home to solar power, you may want to consider only utilizing it to heat your water. Some other types of heating systems are:
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?).
×