The heat pump gained popularity in the 1950s in Japan and the United States.[13] Heat pumps can extract heat from various sources, such as environmental air, exhaust air from a building, or from the ground. Heat pumps transfer heat from outside the structure into the air inside. Initially, heat pump HVAC systems were only used in moderate climates, but with improvements in low temperature operation and reduced loads due to more efficient homes, they are increasing in popularity in cooler climates.
In most modern homes with up-to-date heating and air conditioning systems, filters are changed regularly through the year, so you may not even need to hire a professional. However, keep your eyes open for the accumulation of dust, dirt, dander and mold. If you see it despite regularly changing your filters it could be an indication you need a high-pressure cleaning.
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.

Asking how much an HVAC installation costs is kind of like asking, “how much does a new car cost?”  Well, are you buying a Porsche or a Honda? Is it a 911 or just a Boxster, and are you going to get the leather seats? Likewise, are you going to get a Carrier or a Goodman air conditioner? Does the ductwork need to be replaced? These are all questions that will affect your HVAC installation cost, so let’s take a closer look.
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 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
We are all getting migraines several times a month. I have asthma but not ever as bad as it has been and my 2 year olds dr just informed me she potentially has asthma too. We all get sinus infections regularly and eczema and contact dermatitis. None of us have been this way until recently in our apartment. A roof leak with mold was repaired recently mold was sealed off not removed. We also had lead paint removed from a few window trims this year. I wasn’t here to see if they covered the vents. We had mice too. I vacuum everyday we have hardwood floors no one wears shoes past the font door and I’m getting over a cup full of dirt every time I vacuum. Dust on everything daily. White dust. It’s a 4 room apartment with 1 intake. They are filthy from what I can see when I change the filters. The filters are black after a few months. I feel bad to ask the homeowner to get the system cleaned, can’t afford to move (we live in the city & it’s expensive). I am going to try the shop vac to remove what I can. Any experienced hvac people please give your opinion. Should I just get it done and pay for it myself? We have lived here for 13 years. It’s never been cleaned since ive been here. Is it something I can do with a shop vac? Can i use a wet rag to get the powder dust on the inside of the vents off. One vent has what looks like chunks of dry wall or thick paint sitting in the vent and none of the vents screw into the wall, the screws just fall out. No one ever reinforced the area so the wall just basically crumbles. Kind of useless to spend the money on filters since the air and dust just blows out around the sides of the vents and one of the vents just falls right out of the wall when the heat is turned on. I don’t know why the owner doesn’t fix it. He’s been here to replace filters and saw the condition.
Duct cleaning is a band aid, like washing you hands is. Under your description, why wash your hands more than once? If it gets cleaned once, it shouldn't get dirty again. Well that is, unless they touch something dirty. Keeping your hands completely clean is virtually impossible. Same as keeping dust out of your home. You clean your ducts and over a 3-5 year span they get dirty again. Also, duct cleaners are not licensed but should be certified by NADCA(National Air Duct Cleaning Association).
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:

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).

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):
Pay particular attention to cooling coils, which are designed to remove water from the air and can be a major source of moisture contamination of the system that can lead to mold growth. Make sure the condensate pan drains properly. The presence of substantial standing water and/or debris indicates a problem requiring immediate attention. Check any insulation near cooling coils for wet spots.
 The A/C System Cleaning and restoration industry has become a very lucrative bait and switch industry that many Carpet cleaning companies, Maid services, as well as plumbing or handyman service companies are adding on to there services. These add-ons are not fully certified, trained or even have any experience in the HVAC industry. These companies are the reason prices and quality of work are all over the place. If you are looking to make a smart decision for your home a professional Duct Cleaning service will protect you for 5-7 years. This info comes from NADCA (National Air Duct Cleaning Association) which is the closest thing to a license we have for duct cleaning. They have a great site that explains this process and pricing much more in depth and factual than what has been written here. This organization is working very hard to get these bad companies exposed and out of this industry. So in saying that do your research! Green Duct Decontamination is a certified company with certified technicians that take this work very seriously. We can not have these low rated unprofessional companies paste a bad name for an entire industry. Stay away from anything under 250$ for a full duct clean this is not feasible, go look at and you will understand why and what these companies are doing to rob you of your dollar.

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.
I originally took off one star because of the SNAFU with getting the part ordered.  When Alberto called me on the phone he admitted the person had "gotten busy with other things" and apologized.  THAT was taking the high road and I was impressed by that.  Sadly, for reasons I won't guess at, Alberto has decided to take the low road in his comments and imply that they got the part as quickly as possible.  Well, we called at 2:30 so did someone spend six and a half hours finding the part??  That seems very doubtful.
If not properly installed, maintained and operated, these components may become contaminated with particles of dust, pollen or other debris. If moisture is present, the potential for microbiological growth (e.g., mold) is increased and spores from such growth may be released into the home's living space. Some of these contaminants may cause allergic reactions or other symptoms in people if they are exposed to them. If you decide to have your heating and cooling system cleaned, it is important to make sure the service provider agrees to clean all components of the system and is qualified to do so. Failure to clean a component of a contaminated system can result in re-contamination of the entire system, thus negating any potential benefits. Methods of duct cleaning vary, although standards have been established by industry associations concerned with air duct cleaning. Typically, a service provider will use specialized tools to dislodge dirt and other debris in ducts, then vacuum them out with a high-powered vacuum cleaner.