The original furnace was a coal fired “octopus” design which had no blower to circulate the air but relied upon warm air rising to distribute the heat. That also means that the system breathed air in from the basement and most of this type did not have a cold air return system. At some point (probably in the 1940’s) the system was upgraded to a forced air gas furnace. The upgrade included replacing the 12″ diameter air ducts exposed in the basement with 6″ ducts and a cold air return system of ducts from the two (only two) air returns on the first floor.

A small number of products are currently registered by EPA specifically for use on the inside of bare sheet metal air ducts. A number of products are also registered for use as sanitizers on hard surfaces, which could include the interior of bare sheet metal ducts. While many such products may be used legally inside of unlined ducts if all label directions are followed, some of the directions on the label may be inappropriate for use in ducts. For example, if the directions indicate "rinse with water", the added moisture could stimulate mold growth.
Professional cleaning involves getting the dust and debris outside, so they use outdoor ventilation equipment. It is so important that homeowners make sure the professional contractor is using good equipment then, as they could otherwise spread the spores into the home and further agitate sensitive family members. In the case of mold, a cleaner will only be able to tell you it is there, followed by needing an additional mold professional to come out and test or remove the mold. Air duct cleaning industries do not require state licensing, so make sure to check for a company with references.
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]
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.

Some research suggests that cleaning heating and cooling system components (e.g., cooling coils, fans and heat exchangers) may improve the efficiency of your system, resulting in a longer operating life, as well as some energy and maintenance cost savings. However, little evidence exists that cleaning only the ducts will improve the efficiency of the system.
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.
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!
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.
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.
You may be familiar with air ducts that are constructed of sheet metal. However, many modern residential air duct systems are constructed of fiber glass duct board or sheet metal ducts that are lined on the inside with fiber glass duct liner. Since the early 1970's, a significant increase in the use of flexible duct, which generally is internally lined with plastic or some other type of material, has occurred.
The sky is the limit. I am a big fan of adding zoning systems, but realize that this will typically add $2,300 to $3,500 (or more) to the price. “Why a price range, isn’t it just a part?” No, the part then has to be installed, and the customized ductwork required will vary based on the difficulty of the job and layout of your attic. It is very labor intensive, and most people don’t do it right. It should also include a bypass damper and ductwork! Simply put, the more you add, the more it will affect your HVAC installation cost.
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.

If you want to get some of the dust and debris out of your ventilation system, you can mix household cleaners like bleach with water, dip a cloth in the mix and then the wipe out the system. This will remove a layer of the spores, which could increase the quality of air a bit and help with the flow of air throughout the house until a pro can come out.


WELL, this summer when I opened them up we had black dust spewing from one of the upstairs vents. It resembled the fuzz that comes off new towels. This prompted us to look into duct cleaning. We heard from someone who had it done several times, said it was worthwhile, and knew of a firm that did a good job. Clean Air America sent a single technician for the appointment and after counting registers and ducts gave me a price of $360.00 which included “sanitizing” the system (a $99 additional fee per can used). The small size of the plenum forced him to connect the 8” round vacuum hose from the truck to the 10” square opening from our humidifier unit. In hindsight, a mistake since it reduced the “negative” pressure in the system.
Appliance Maintenance Book Snow Blower Maintenance Appointment Schedule Appointment for HVAC Maintenance Carpet Cleaning Services Air Duct Cleaning Services Handyman Service Riding Mower Maintenance Sears Warranty and Satisfaction Guarantee Heating and Cooling Home Renovation Tulsa Window Replacement Home Kitchen Design Roof Installation & Replacement Service Home Improvement Cabinet Refacing & Replacement Home Improvement
Before we get to HVAC installation prices, we will first need to briefly discuss some terms, definitions, and factors that will affect how an honest HVAC installation company determines their prices. Notice that I said honest. Unfortunately, there are dishonest people out there. There always have been, there always will be, and there is a good chance that you had an experience with such a contractor, which is what drove you to read this article. I can’t teach you how to tell if someone is honest, but I can give you the knowledge to help you decide. Take a look at How to Choose an HVAC Contractor for tips on what to look for.
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:
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.
I called a company name “GREEN RHVAC” with their $29.00 one system air duck cleaning. When the guy came with a truck I asked him to tell me how much he will charge and he said that if he gave me price and I didn’t want the service then he would charge me $89 or he would tell me how much he charge me after he finished the work. I immoderately sense that I made mistake to call him to my house. To cut my lost I asked him to give me the price and it was $1600 for two systems house. I paid $100 to him for my lesson to learn and search online to find this site is very helpfully and I should do it before to call anyone for air duck cleaning.

Metal is way better than flex duct or ductboard. It gets better airflow, holds up to critters and duct cleaners. I know of no hvac company here that cleans ductwork. (there probably is one somewhere) The mfg's of duct cleaning equipment keep trying to sell us hvac people on their benefits and profit potential but most all hvac people know that unless you have metal ductwork you are NOT doing the customer any favors.

Greetings from Mama Duck from Ductz of Greater Atlanta. These are some awesome comments and a few are from high quality duct cleaners that I personally know. After 19 years in this industry I agree that a government agency is not always up to date with their knowledge but won't admit it. If they were out in the field with our technicians every day they would upgrade their info. I get calls all the time where customers have been taken advantage of by "go and blow" companies. The customers don't know what they don't know but many are too lazy to do the research and are just looking for cheap. The industry has gotten a bad rap due to these con artists but the customer has to take some responsibility. I ask them why they would want to do business with a company who lies to them in print? Are they stupid or just cheap? Thankfully there are those of us in the industry who are working diligently to raise the bar on quality, protect the consumer and perform high quality work. At Ductz all our technicians are NADCA certified, trained by the best in the industry and know how to clean the entire system.


Deciding if central air is worth the cost depends on your needs and local housing market. If you live in a hotter climate, it can definitely be worth the price. Not only can it keep your home at a comfortable temperature, but air conditioning can even save lives during extreme heat waves. But in a milder zone without severe temperatures, window units, fans or the breeze from an open window could be adequate.
"Customer service was great, and the price was in-line with other places, and fast service. We had a whole replacement of the outside and inside. I would have liked to see a better install for the furnace and new thermostat - the new thermostat should have gone where the old one was, and even tho the new furnace was a tight fit, they didn't offer to come back and repair the case molding, or give me a discount on the damage done, and I believe they should have put a disconnect box on the outside of the home, to make it easier for any future repairs needed. Other than that, am very happy with the cooling and heating!"
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