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.
Mitsubishi Electric is a world leader in air conditioning systems for residential, commercial and industrial use. Challenged to create air conditioning systems that provide exemplary performance in the wide-ranging climatic conditions found throughout Japan, our engineers develop amazingly sophisticated yet durable units and systems capable of constant use under virtually any natural climatic condition on earth.
Natural ventilation is the ventilation of a building with outside air without using fans or other mechanical systems. It can be via operable windows, louvers, or trickle vents when spaces are small and the architecture permits. In more complex schemes, warm air is allowed to rise and flow out high building openings to the outside (stack effect), causing cool outside air to be drawn into low building openings. Natural ventilation schemes can use very little energy, but care must be taken to ensure comfort. In warm or humid climates, maintaining thermal comfort solely via natural ventilation might not be possible. Air conditioning systems are used, either as backups or supplements. Air-side economizers also use outside air to condition spaces, but do so using fans, ducts, dampers, and control systems to introduce and distribute cool outdoor air when appropriate.

The three major functions of heating, ventilation, and air conditioning are interrelated, especially with the need to provide thermal comfort and acceptable indoor air quality within reasonable installation, operation, and maintenance costs. HVAC systems can be used in both domestic and commercial environments. HVAC systems can provide ventilation, and maintain pressure relationships between spaces. The means of air delivery and removal from spaces is known as room air distribution.[3]
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.
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
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!

Preventing against air leakage is great, but the only way to keep dust and debris out of a duct system would be to completely seal off the return-air side of the system, which would render the system useless. Cold-air returns will always pull dust and other particles into the system. A high-MERV rated filter is definitely a good idea, but it does nothing to keep the return side of the system clean. Definitely agree though to use foil tape to seal seams, etc. Duct tape dries out over time and as it does can actually add more particles to the air.
Engineers have pointed out some areas where efficiency of the existing hardware could be improved. For example, the fan blades used to move the air are usually stamped from sheet metal, an economical method of manufacture, but as a result they are not aerodynamically efficient. A well-designed blade could reduce electrical power required to move the air by a third.[28]
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.
I purchased one of those Amazon air duct cleaning coupons for 49.99. When the company showed up, they removed the vent closest to the air intake and immediately told me I needed $1800.00 for all new duct work. They said they could not clean the system until new duct work was installed. I thanked them and said I would give them a call. The only call I made was to Amazon to get a refund. I know I didn’t need new duct work. Be careful to not fall for unscrupulous salesmen and their pitches and scare tactics.

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.
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.

This is where i found where the major problem was for the dust problem in my home. I took down the sheet metal that was 16" wide down by taking the screws out that keep it attached and when i took it down i, could not beleive the amountbof dust that was up there, inhad to put on breathing nasks to actually scoop out all the cust with my hads and then i used my shop vac then bleached everything, i would say that i filled up a 5 gallon maybe more not counting all the dust that was attached to the side of the beams that was all wood , because the contractor did not actually build a 16" wide return all out of metal , butvinstead used the sheet metal plate as a short cut to make a suare box using my beams in my basement to make a suare box. I was told contractors do that often and i feel that should be outlawed because it caused my sinus and allery problems,nwhich almost caused me to die. so everyone should make sure their ductwork was made properly. Yes seal it . Cover all openings. So it was not the contractors fault that my vents still had dust, in them, he was afraid tomgetvon top of my pool table to try to get iside the short cut ductwork with the 16" wide sheet metal. To everyone, make sure you clean your vent system. And make sure you could see it visually like i did , neither i or the contractor had no clue the problem was right above my pool table because of the make shift ductwork. The contactor shoul have made a squrae duct like the rest instead of using my beams as a short cut. That could be whyba lot of people start to have major allergy problems and maybe even ashma.so coverall holes to prevent dust to be taken in and all bugs etc. then make sure you clean your ductwork as you see reasonable, they say every 5 years , but i say evry 2 to 3 years, but you can do it yoursely.. You need a good air hose and suction vacum like a shop vac, do a little research. I invented something a while back like 18 to 20 years ago , and now it is on the market to help homeowners such as ourselves with this dust problem. I cannont say anymore because i have to make sure that it was not my research and idea that solved my problem and for all the others that are using what i invented ..there was nothing on the patent search that i hired an invention company to do, back then. Once yor vents are cleaned properly younwill be very happybif you are an allery sufferer. Stop the children for throwing things into the ductwork and sweeping things into the ductwork, keeping your vent system is clean once youbclean it right the first time, just maintain it , you dhould keepmthe hvac system clean such as coils etc it truly helps,people vome into my condo and they cannont beleive how cold it igets and how my system works so well. it is because i have my whole duct system sealed outsid with the duct sealant and my coils i vleaned my self and take the time that the furnase fan is cleaned because that could have a lot of major dust attached to it, mine had a lot of caked on dust it was like hard dirt. Yxounwill save on allergy bills nasal sprays, i wish I could say more because incould say something to really keep your whole duct system clean for years once you do a first good cleaning of intake and return vents. until i email one of the major companies to see where they got my idea from. Intrulybhope it was not from the invention company i hired years ago who did the patent search for my idea. I becam
Pro HVAC company Southern Comfort Mechanical says on its blog, “If there’s mold growth inside the handler due to excess moisture, algae in the condenser drain line or a dirty evaporator coil, it can negatively impact your AC unit’s efficiency. The filters inside may also build up excess dirt and become clogged, which will also make your AC [or heat pump] waste energy trying to sustain the cool climate inside your home.” These issues are easy to solve. They don’t require replacing the air handler.
HELP is am drowing in LENT . It has been noticed in the master bedroom there is lent all over the furniture and the floors. I have dark brown/black furniture and same for the wooden floors. There are wods of lent every day. My furniture covered in lent. The rest of the house is fine just the tipical dust. I am sure my lungs are also full of lent. I looks like if my dryer vent was in my bedroom. Please help
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]
I am very interested by your post. We recently had a lead inspection on our property and one thing the lead inspector suggested was to get the air ducts cleaned out. We had our ducts cleaned last year after we under went a large renovation project (since we have a toddler in the house). This year we decided to go for lead compliance and had all our lead removed (we moved out for the work). Recently, my son had a false positive lead test, which prompted us to get a lead dust inspection around the house (including having the vents dust-wiped on the inside). The levels inside the ducts weren't crazy high (but more than would be acceptable for a floor). As it turned out my son's lead levels are very low (but not zero). Is it possible however that lead dust from the inside of a vent can come out? Would this be a scenario where you think air duct cleaning would be beneficial?
Unfortunately, manufacturers and contractors don’t publish this information…it’s a secret. Why? Who knows…but we have access to a full contractor pricing database of 1,000’s of different units in our online HVAC installation cost calculator, so let’s choose one for our example calculation. We’ll go with Carrier equipment, since our readers always bother us about them (despite us telling them that they are overpriced):

PickHVAC Tips: Don’t be sold on systems with features you don’t want or need. Called “upselling,” it is rampant in the HVAC industry. Some features are nice – if you want them. If your single-stage furnace was loud and pushed out cold air at the start of the cycle, then a two-stage model will improve those issues. If you didn’t notice them, the upgrade will be a waste of money. That’s just one common example.
Important Tip: Don’t just pay attention to the high-end of the price range! – which is what I know you are all looking at, but also look at the low range. If a contractor is cheaper than this, ask “why?” Usually it is because they don’t have liability insurance, workman’s compensation insurance, are unlicensed, all of the above, or worst yet, they don’t use HVAC technicians. You are spending a lot of money.  Make sure that they are licensed (In California, check here at CSLB License Checker) and insured.
The letters in HVAC stand for heating, ventilation and air conditioning. An HVAC system enables you to regulate your home or building’s internal temperature (thermal control) for comfortable living and working. You can bring heat levels down in the summer and up in the winter, keeping your home or office livable year-round. HVAC systems can also help with humidity levels and regulate indoor air quality in a home or office. There are many types of HVAC systems and technologies available.
I live in a 1950's ranch house in the South. The prior owners were smokers. Based on recommendations from one of the local conservation organizations, I decided to have a home energy audit done. As part of their findings, they recommended additional insulation in the attic and duct cleaning and sealing. This turned out to be a very problematic process. In terms of the ducts, it was necessary to remove the metal grates. However, these grates had been painted over many times and shoe molding covered the bottom of the grates. The vendor was not able to remove the grates without damaging them in the process. Because these grates dated back to the 1950's, it was difficult to find appropriate replacements. The ones I finally discovered were correct except they were 1/4" wider. This meant that the shoe molding had to be carved out. The duct cleaner could not provide any assistance with this problem. It took me a month of long evenings replacing the vent covers myself, carefully chiseling out the shoe molding and repainting. In terms of the extra installation in the attic, the same vendor used blow in insulation. Unfortunately, they did not recognize that the 13 floodlights whose mounting extended into the attic were not designed to be buried under insulation. The problem manifested itself in terms of expensive flood light bulbs failing continually. So, I had to have all of the light housings replaced. Yet another unexpected expense. Despite the expense, pain and suffering, I cannot report any improvement in my heating costs or the "quality" of the air. To be fair, I do not have any allergies and did not undertake this for air quality improvements but rather heating efficiency improvements.
Heating, ventilation, and air conditioning (HVAC) systems have been shown to act as a collection source for a variety of contaminants that have the potential to affect health, such as mold, fungi, bacteria, and very small particles of dust. The removal of such contaminants from the HVAC system and home should be considered as one component in an overall plan to improve indoor air quality.

I’m having my duct work cleaned this Saturday. Have a coupon for $49 through Amazon. Job normally $249. Had my basement remodeled about 18 months ago. The contractors were very thorough at blocking the vents, as far as I can tell. The offer is for HVAC and dryer vent cleaning. My house is 11 years old. I figured, $49 is not much. I appreciate your tips on not getting talked into any additional service, not to use solvents to clean, the certification information and before and after pictures. Very useful and I’ll be sure that all I spend is the $49 for the voucher.
If you are replacing your air conditioning system, make sure that the unit is the proper size for your needs and that all ducts are sealed at the joints. A unit that is too big will cycle on and off frequently, resulting in poor moisture removal, particularly in areas with high humidity. Also make sure that your new system is designed to manage condensation effectively.
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.

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]
Ground source, or geothermal, heat pumps are similar to ordinary heat pumps, but instead of transferring heat to or from outside air, they rely on the stable, even temperature of the earth to provide heating and air conditioning. Many regions experience seasonal temperature extremes, which would require large-capacity heating and cooling equipment to heat or cool buildings. For example, a conventional heat pump system used to heat a building in Montana's −70 °F (−57 °C) low temperature or cool a building in the highest temperature ever recorded in the US—134 °F (57 °C) in Death Valley, California, in 1913 would require a large amount of energy due to the extreme difference between inside and outside air temperatures. A few feet below the earth's surface, however, the ground remains at a relatively constant temperature. Utilizing this large source of relatively moderate temperature earth, a heating or cooling system's capacity can often be significantly reduced. Although ground temperatures vary according to latitude, at 6 feet (1.8 m) underground, temperatures generally only range from 45 to 75 °F (7 to 24 °C).
Because an air conditioner moves heat between the indoor coil and the outdoor coil, both must be kept clean. This means that, in addition to replacing the air filter at the evaporator coil, it is also necessary to regularly clean the condenser coil. Failure to keep the condenser clean will eventually result in harm to the compressor, because the condenser coil is responsible for discharging both the indoor heat (as picked up by the evaporator) and the heat generated by the electric motor driving the compressor.
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.
Is duct cleaning worth it? There is not a yes or no answer that suits everyone. On an Air Force base, the system was not air tight and there was leakage around the filters. The system got dirty. A professional company was called out. The Duct was big enough that a technician could go inside the metal duct and clean it. There was a new Air Handler installed and things were sealed up better. in this case it was worth it.
You might also want to check your home for thermal insulation if you live in extreme heat or freezing temperatures. Insulation keeps the heat and cool air in your home, which can lead to a lower electric bill. If the heated or cool air leaks out, your system turns on more often. There are various types of insulation that you can install in your home and a home energy auditor can point out the best places for it in your house.
The answer to your question is most likely "Yes," but not defiitely. It depends on where the dust is coming from. Now, if your house is more than say, 12 years old then you likely do have leaks in your ducts that can let in insulation particles and dust from your attic. If this is the case then cleaning of the ducts-PROPER CLEANING, which like the article sas doess include EVERYTHING that the conditioned air passes through, such as your indoor evaporator coil and blower housing assembly-is definitely a good first step to getting that dust under control! Of course I highly recommend that you also have your ducts SEALED as well, or else you will have to repeat the cleaning some time down the line. As a 3rd step, consider an electronic air filter. I always thought they were a scam, personally, so I never bothered selling them to my clients. Then one day my manager sent me to install one for a senior couple in a mobile home. The wife had bad allergies, and her eyes were constantly watering and puffy and red. Well, I did a quality check 60 days later and she could not stop praising that air filter! Keep in mind that in a mobile home, duct seals are not as complete as those in other homes due to access issues.
Dehumidification (air drying) in an air conditioning system is provided by the evaporator. Since the evaporator operates at a temperature below the dew point, moisture in the air condenses on the evaporator coil tubes. This moisture is collected at the bottom of the evaporator in a pan and removed by piping to a central drain or onto the ground outside.
Your contractor will do a load calculation to determine the proper central air conditioning unit for your home. This calculation accounts for the climate, size, shape and orientation of your home, as well as its square footage. A professional will also look at the insulation, windows, walls, floors and other materials that compose your home. He/she will then examine any leaks, seals and existing ducts or vents.
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.

Window air conditioners cost less than central units, averaging $300. These systems generally suffice to keep a room cool on warm spring and summer days. They can bring added comfort for a reasonable price but are less powerful than a central air conditioner. If you have a bigger home with multiple rooms, you will probably need to have a larger system installed. Central air can cool several rooms at once, while window AC units usually only cover one or two rooms at a time.


Refrigerant Metering Device -- Every HVAC system has one of these, and heat pumps have two. They regulate the amount of refrigerant going through your air-conditioner. If it fails, either too much or too little refrigerant will course along the lines and either not perform well or will overwhelm the compressor and cause it to fail. A total failure of this component will result in a complete loss of operation.
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.

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 an HVAC company. Dirt in your ducts stays there and hurts no one. It is like dirt on the ground outside. This industry was infiltrated by a bunch of money grubbing low lifes years ago. As a credible company, we do not clean air ducts. Some who were credible probably signed on not knowing what else to do or to try to make a buck another way. These companies, because they also do HVAC work not only rip off private homeowners, they are ripping off legitimate HVAC company's customers and the integrity of what can and should as a rule be a great service industry. Some probably have gotten into this to simply offer what competitors who were ripping off their customers were offering. Anyone cleaning ducts is in my opinion raising a big red flag that they cannot and should not be trusted. Political pressure from NADCA, advertising dollars, manufacturers and marketers of duct cleaning equipment, and intense competition for the customers is the only reason the government and adverstising companies have not run them out of business and that this cancer perpetuates itself.
Natural ventilation is the ventilation of a building with outside air without using fans or other mechanical systems. It can be via operable windows, louvers, or trickle vents when spaces are small and the architecture permits. In more complex schemes, warm air is allowed to rise and flow out high building openings to the outside (stack effect), causing cool outside air to be drawn into low building openings. Natural ventilation schemes can use very little energy, but care must be taken to ensure comfort. In warm or humid climates, maintaining thermal comfort solely via natural ventilation might not be possible. Air conditioning systems are used, either as backups or supplements. Air-side economizers also use outside air to condition spaces, but do so using fans, ducts, dampers, and control systems to introduce and distribute cool outdoor air when appropriate.
When central air conditioning service fails during a heat spell, you may have to wait days for an HVAC repair technician or an ac contractor to show up, and you'll probably pay at least several hundred for the repair. But if you're comfortable working around electricity and are willing to spend about $50 on parts, you can probably repair your air conditioning service yourself in about two hours and save about $225 on parts markup and labor.
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