I to had an odd layer of white'ish dust building up especially during seasonal periods when the HVAC ran a a lot. I carefully swept up the fine dust into a small pile and had it analyzed. Turns out it was very fine fiberglass powder dust. It turns out it is the insulation form the attic! (My attic has blown in insulation). Turns out if you (I) had small gaps around my HVAC registers in the ceiling whee the airs blows into the room. What occurred in my case was that the exiting air at that seam creates a vacuum effect at the grate vent cover and draws and then blows fine insulation dust from the attic into the house. Removing each register grate and sealing each tin outlet gap with calking between the dry wall ceiling and tin fixed the issue. A couple were so bad with bowed gaps I had to screw down the bowed tin to the attaching stud better. Checking the very same glass top desk that catches and shows any dust accumulation now shows only very small amounts of normal house dust build up over several weeks. A big, big improvement. You might have a look by simply removing a couple vent covers yourself.
You may consider having your air ducts cleaned simply because it seems logical that air ducts will get dirty over time and should be occasionally cleaned. Provided that the cleaning is done properly, no evidence suggests that such cleaning would be detrimental. EPA does not recommend that the air ducts be cleaned routinely, but only as needed. EPA does, however, recommend that if you have a fuel burning furnace, stove or fireplace, they be inspected for proper functioning and serviced before each heating season to protect against carbon monoxide poisoning.
Although most new homes have ducts and vents already in place, many older homes have old convection heating systems or baseboard heaters without ductwork. In such cases, you will need to install ducts and vents to provide the air conditioning with a flow system. This would be the time to explore upgrading the existing heating system as well, as it will be much cheaper to do together.

These are the prices for a proper installation from a professional – as a word to the wise, HVAC systems require fine tuning and the custom fabrication of parts during installation to work properly, otherwise they will likely fail prematurely. But there are plenty of people who will do it for cheaper than this, using substandard, used, or stolen equipment (stolen from construction sites and new housing developments). Or, they are using unskilled laborers with no experience, etc. But HVAC is not a “we’ll figure it out trade;” there is a right way and a wrong way to do things. There are just too many predatory companies out there, so be careful. I’d highly recommend not skimping on your HVAC contractor. If you go cheap, you will typically pay more in the long run...and in California, that will be a lot!
My vent covers have lots of mildew. They look bad! I live in a very humid climate in a condo. The handyman here has offered to take those down, wash them, sand, & then spray paint them with a mildew resistant paint. He said that he will leave them off overnight to dry. I am wondering if this is safe to breath the AC blowing out into the open all night??. ! Guess it is better than the mildew!?
Multiple inventions within this time frame preceded the beginnings of first comfort air conditioning system, which was designed in 1902 by Alfred Wolff (Cooper, 2003) for the New York Stock Exchange, while Willis Carrier equipped the Sacketts-Wilhems Printing Company with the process AC unit the same year. Coyne College was the first school to offer HVAC training in 1899.[12]
Without proper ventilation, carbon monoxide can be lethal at concentrations of 1000 ppm (0.1%). However, at several hundred ppm, carbon monoxide exposure induces headaches, fatigue, nausea, and vomiting. Carbon monoxide binds with hemoglobin in the blood, forming carboxyhemoglobin, reducing the blood's ability to transport oxygen. The primary health concerns associated with carbon monoxide exposure are its cardiovascular and neurobehavioral effects. Carbon monoxide can cause atherosclerosis (the hardening of arteries) and can also trigger heart attacks. Neurologically, carbon monoxide exposure reduces hand to eye coordination, vigilance, and continuous performance. It can also affect time discrimination.[15]
A little simple math can help determine the size system you need. A rule of thumb is 20 BTUs per square foot. So, a 500 square foot room would need 10,000 BTUs to cool or warm it efficiently. This assumes that you live in a temperate region and have adequate insulation with no energy loss. In the real world, all units have some degree of energy loss. This is reflected in an HVAC system's SEER rating for cooling and AFUE rating for heating.
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.
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.

2. If air quality is so important and duct cleaniliness is so uncertain, why not adopt doubling filtering; that is, in addition to the existing main furnace filter, add a filter at each air outlet. I understand replacing so many filters would be a burden, but air outlets can be designed for easy filter replacement. The builders and home design engineers should bear responsibility to provide good and low maintenance homes, rather than prioritizing on fancy or costly featuers for homes.


On average, we (Indians in Ontario) receive 3-5 calls per day for duct cleaning services from India. I did get ducts cleaned twice in 25 years. For a newly built house, it should be done as material goes into the ducts. Every year, before turning the heat on, I clean the ducts, using the vacuum pipe or with wet towel. Most of the dust, pet hair, small items get to the ducts from the top floors, not where system is installed. Even in winter months, I open 2-3 windows for air circulation for 15 minutes, specially right after cooking, almost daily. We breath in the same stale air, develop health issues. Also, I have an added air cleaning and fileration system installed. At a low rate, this system constantly cleans the inside air and also that it pulls from the outside. Duct cleaning is a scam, there are other efficient and cost effective methods we can use to purify the inside air.
Monday the following week, no phone calls, or follow up.  I call to get an update and am told that they cannot install my system because they don't have time.  I ask what does that mean, one year? One week? Until the end of summer they say.  What does that mean I ask?  They say at the end of September.  I say thank you for wasting 1 month of my time.
Installing a split system may involve making modifications to the house itself for the necessary lines to be run. The heat exchangers are also more prone to picking up debris and must be cleaned on a regular basis. While they come with protective screens over the fan, care must still be taken to ensure that nothing gets in, especially in a home with children.
Feel perfectly comfortable at home with our innovative Lennox Residential heating, cooling and air quality systems. Lennox manufactures high-efficiency HVAC systems including furnaces and air conditioners designed to conserve energy and save money. Our complementing air filtration systems, humidifiers and dehumidifiers help keep indoor air quality healthy and clean.

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.
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.
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.
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