We understand having problems with your air conditioning system - can be frustrating and uncomfortable. That's why Gator Air Conditioning only employs background checked, drug tested, highly trained and certified technicians. And we are so confident in their skill to correctly diagnosis and complete your Air Conditioner repair that we cover them with our Fixed Right Guarantee. Our Comfort Advisors come from the industry with the technical expertise needed to ensure the air conditioning systems we quote will be sized right to maximize performance. We employ the best air conditioner installers in Bradenton, FL to ensure your air conditioning system will be installed right to meet or exceed manufacturer recommendations. For your peace of mind, our Installation Guarantees cover more than just the equipment… we also cover your money, time, our workmanship, and your satisfaction.


The contactor (relay) and start/run capacitor(s) (see illustration below) fail most often and are inexpensive. So it’s a safe bet to buy and install those parts right away, especially if your air conditioning service unit is older than five years. The condenser fan motor can also fail, but it runs about $150 — hold off buying that unless you’re sure that’s the culprit.

The fan limit switch controls the furnace blower. The fan limit switch has three settings: “Fan On”, “Fan Off”, and “Limit”. In the “Fan Off” setting, the blower will only operate if there is warm air in the plenum to prevent cool air from blowing into the home. The “Fan On” setting will keep the blower operating even after the burner has shutdown, making sure that all of the hot air produced is circulated. The “Limit” setting is a safety control that will turn the burner off in the rare event that the air in the warm air plenum reaches an unsafe temperature. This may be the case if ducts are blocked or if the system controls are malfunctioning.
Packaged terminal air conditioner (PTAC) systems are also known as wall-split air conditioning systems.[36] They are ductless systems. PTACs, which are frequently used in hotels, have two separate units (terminal packages), the evaporative unit on the interior and the condensing unit on the exterior, with an opening passing through the wall and connecting them. This minimizes the interior system footprint and allows each room to be adjusted independently. PTAC systems may be adapted to provide heating in cold weather, either directly by using an electric strip, gas, or other heater, or by reversing the refrigerant flow to heat the interior and draw heat from the exterior air, converting the air conditioner into a heat pump. While room air conditioning provides maximum flexibility, when used to cool many rooms at a time it is generally more expensive than central air conditioning.
When you change the temperature on your thermostat, or the temperature in your home drops, a signal lets the furnace's igniter know that it's time to turn on. Igniters exist in both hot water boilers and forced air furnaces, replacing pilot lights as the switch your unit needs to kick on. Naturally, this is a core part in making sure it works reliably. When it stops working, your unit will not longer know when to actually heat your home. Fortunately, furnace igniter repair doesn't tend to be a major budget problem, and costs less than $300 on average.
Most Michigan HVAC repair companies will often charge a “Travel Charge” or “Diagnosis Fee.” Randazzo calls this fee simply, a “Service Call Fee.” This will be the minimum cost of the repair. It is not recommended to judge a company on how expensive or how cheap their service rates are. In most cases, with larger companies the rates will be higher. This is not because they may have more overhead but simply because of the quality and preparedness of the service that will be preformed.
Heaters are appliances whose purpose is to generate heat (i.e. warmth) for the building. This can be done via central heating. Such a system contains a boiler, furnace, or heat pump to heat water, steam, or air in a central location such as a furnace room in a home, or a mechanical room in a large building. The heat can be transferred by convection, conduction, or radiation.
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. 

Recent Review: Metro Service was amazing. They came out on Saturday and secured the gas to a failing furnace to insure our safety. They came out on Monday and had the new furnace installed and operating within less than 4 hours. Polite, professional, meticulous and 35% lower than their competitors. I will be using them for all of my HVAC needs in the future.
Air Conditioning Your home's air conditioner is an essential part of your overall indoor comfort. A properly working system can mean the difference between a cool, comfortable summer and a hot, miserable few months. If you're currently dealing with a broken air conditioner, an inefficient system, or you would like to schedule a routine, pre-season tune-up, Horizon Services is here to help!
Air-source heat pumps are more popular in milder winter climates where the temperature is frequently in the range of 4–13 °C (40–55 °F), because heat pumps become inefficient in more extreme cold. This is because ice forms on the outdoor unit's heat exchanger coil, which blocks air flow over the coil. To compensate for this, the heat pump system must temporarily switch back into the regular air conditioning mode to switch the outdoor evaporator coil back to being the condenser coil, so that it can heat up and defrost. A heat pump system will therefore have a form of electric resistance heating in the indoor air path that is activated only in this mode in order to compensate for the temporary indoor air cooling, which would otherwise be uncomfortable in the winter.
A multi-split system[44] is a conventional split system, which is divided into two parts (evaporator and condenser) and allows cooling or heating of several rooms with one external unit. In the outdoor unit of this air conditioner there is a more powerful compressor, ports for connecting several traces and automation with locking valves for regulating the volume of refrigerant supplied to the indoor units located in the room.
Leave gambling to the casinos! When it’s 110 degrees in the shade, you don’t want take a chance with a broken AC. Go beyond a tune-up and Rejuuuvenate! your air conditioner back to factory fresh conditions. Your AC shouldn’t sound like a slot machine, so we believe in eliminating every squeak, rattle and hum because if you don’t, bigger problems will come. So trust our highly trained, screened, and “Sadie Certified” technicians to make you the coolest act on the Strip!
Air flow meter Aquastat BACnet Blower door Building automation Carbon dioxide sensor Clean Air Delivery Rate (CADR) Gas sensor Home energy monitor Humidistat HVAC control system Intelligent buildings LonWorks Minimum efficiency reporting value (MERV) OpenTherm Programmable communicating thermostat Programmable thermostat Psychrometrics Room temperature Smart thermostat Thermostat Thermostatic radiator valve
We had an exceptional experience with Gator Air, in particular Carlos. He presented us with quotes for different types of AC units, told us facts about said units and left us to make our decision. No high pressure sales. The installers were professional and cleaned up when they were through. A nice surprise was the 1 year free maintenance of the unit. We belonged to the Gator Club so to not have to pay it for the next year was an added bonus. Thank you GatorAir for making the experience an enjoyable one.
In hot weather, air conditioning can prevent heat stroke, dehydration from excessive sweating and other problems related to hyperthermia. Heat waves are the most lethal type of weather phenomenon in developed countries. Air conditioning (including filtration, humidification, cooling and disinfection) can be used to provide a clean, safe, hypoallergenic atmosphere in hospital operating rooms and other environments where proper atmosphere is critical to patient safety and well-being. It is sometimes recommended for home use by people with allergies.
Hii need you guys help! Once my thermostat drop below the set temp , my furnace does not turn on and I was wondering what’s wrong with it. It happens mostly on cold nights. Sometimes I would have to go in the basement and turned the furnace power switch off then on and will come on once I switch it off then on.i also change the thermostat recently, so I don’t think that’s the problem
In 1995, Germany made CFC refrigerators illegal.[22] DuPont and other companies blocked the refrigerant in the U.S. with the U.S. EPA, disparaging the approach as "that German technology".[21][23] Nevertheless, in 2004, Greenpeace worked with multinational corporations like Coca-Cola and Unilever, and later Pepsico and others, to create a corporate coalition called Refrigerants Naturally!.[22][24] Then, four years later, Ben & Jerry's of Unilever and General Electric began to take steps to support production and use in the U.S.[25] In 2011 the EPA decided in favor of the ozone- and climate-safe refrigerant for U.S. manufacture.[17][26][27]
The Environmental Protection Agency (EPA) requires that all technicians who open a system containing a controlled refrigerant be certified to do so. There are four levels of certification, one of which is a “universal” certification to allow the HVAC technician to work on any type of equipment containing refrigerant. Your HVAC technician should be certified as “Level II Certified” at a minimum or, preferably, “Universal Certification” to work on your central air conditioner. Obtaining this certification information from your professional HVAC technician may be required in the event you are working with a realtor to sell your home. Costs for certification average $40 to $240. 

An annual inspection of your unit can ensure that the various potential problems mentioned above are detected early, and before they require complete replacement. During this inspection, for instance, a professional might find small cracks in your heat exchanger or a faulty seal in your blower motor. Some manufacturer's warranties even require these annual inspections to maintain validity. Typically, your furnace inspection will cost between $80 and $150 depending on the area in which you live and the professional you work with.

If your furnace needs to be repaired, you’ll want to find a qualified heating, ventilating and air conditioning (HVAC) repair technician. Each state has its own licensing requirements; some require all HVAC technicians to have an HVAC license, while others only require someone operating an HVAC service and installation company with employees to hold a contractor’s license. For example, in Alabama, the Alabama Board of Heating Air Conditioning, and Refrigeration Contractors regulates licensing, while in Kansas there is no state regulatory body and HVAC licensing can vary by region. For simple furnace repairs like changing out a filter, a trusted handyman can probably handle the job, but a trained professional should be hired for tasks like replacing a gas valve, installing a new inducer fan motor or other critical furnace repair jobs that involve dealing with gas leaks or other dangerous conditions. For more, check out our tips for smart hiring on Thumbtack.
When your furnace needs immediate repair, trust the professionals at BGE HOME. We understand that furnace problems are more than a mere inconvenience – they can have a serious impact on the health and safety of you and your family. Our technicians are available 24-hours a day for emergency repairs. Click to schedule your repair and have peace-of-mind knowing that a licensed, certified HVAC technician will have your system up and running as quickly as possible. For 24-hour emergency furnace repair service, call 1-888-243-4663. 

The use of CFC as a refrigerant was once common, including the refrigerants R-11 and R-12 (sold under the brand name Freon-12). Freon refrigerants were commonly used during the 20th century in air conditioners due to their superior stability and safety properties. When they are released accidentally or deliberately, these chlorine-bearing refrigerants eventually reach the upper atmosphere.[61] Once the refrigerant reaches the stratosphere, UV radiation from the Sun homolytically cleaves the chlorine-carbon bond, yielding a chlorine radical. These chlorine radicals catalyze the breakdown of ozone into diatomic oxygen, depleting the ozone layer that shields the Earth's surface from strong UV radiation. Each chlorine radical remains active as a catalyst until it binds with another radical, forming a stable molecule and quenching the chain reaction.

Some of the things that determine air conditioning capacity in Arizona include, but are not limited to: your area’s unique climate, monsoon humidity, number of windows, their location, and their NFRC rating, ceiling and wall insulation factors, which direction your home is facing, how much heat your appliances produce, how high your ceilings are, if you have a basement, if you have proper attic ventilation, the location of trees on your property, and even the number of people who occupy the home.


Although your AC may continue to work for a time, if you ignore warning signs of air conditioner repair troubles, it can be much more costly to repair in the long term. Diminished cooling capacity not only makes your home uncomfortably warm, but it also raises your utility bills significantly as your unit struggles to maintain the desired temperature ineffectively. A system put under strain is likely to overheat, resulting in major damage. Therefore, it is best to have your air conditioner repaired promptly when you discover signs of trouble. 
I'm looking about spanning 15' for a gazebo. trying to figure out what dimension beams I need. The Gazebo will be 15'x10'. How big will the beams have to be. at 1/2 the distance on 15' I will have a perpendicular beam running to carry 2x4's running parallel to 15' beam edge. I live in California in there with be no roofing material.. I will be using redwood for lumber Thanks
During our formative years, we were a member of the Refrigeration Service Engineers Society (RSES). Since then, we have been a long-standing member of the Better Business Bureau (BBB) and are closely aligned with Trane. We are a Certified Trane Dealer and Trane Comfort Specialist—the highest level of certification awarded by Trane. In fact, we have earned the Trane Distinguished Dealer Award 11 times!
We want to compliment your fine sales and installation team. They are outstanding. Carlos, your sales rep., was highly informative. We reviewed our needs and we ultimately chose the Trane XV-18 variable speed system. Carlos did not try to up sell us with things that we did not need but he did help us choose the correct upgraded filter and UV light that we wanted. We told Carlos that our research indicated that the quality of the installation of the unit was at least as important as the unit itself, and Carlos agreed. Carlos pointed out that new proper sized duct work and copper wiring would be required for a correct installation, and that we needed to add two more returns. We asked if more returns were needed and Carlos said that would not be cost effective. That was great to hear. Carlos assured us that the installation team of Willie and Gary, both lead installers, would be used. They were both superb. They came on time and worked for 12 and 1/2 hours. It was a 93 degree day so the heat in the attic was intense. We kept telling them to take a break but they continued to work up there in what must have been 130+ temperatures. They were amazing! They were neat and cleaned up any mess they made. They patiently answered all of our many questions and gave us helpful tips. They were truly professional in all respects. We also note that Stacy, Angie and Karen of your office staff were each courteous, accommodating and efficient. They helped things to go smoothly. Carlos, Gary, Stacy, Angie, Willie and Karen are each great assets to your company. We would be comfortable recommending that team of people to anyone! Ken and Kathy Luban
An air conditioning system, or a standalone air conditioner, provides cooling and humidity control for all or part of a building. Air conditioned buildings often have sealed windows, because open windows would work against the system intended to maintain constant indoor air conditions. Outside, fresh air is generally drawn into the system by a vent into the indoor heat exchanger section, creating positive air pressure. The percentage of return air made up of fresh air can usually be manipulated by adjusting the opening of this vent. Typical fresh air intake is about 10%.
When your furnace needs immediate repair, trust the professionals at BGE HOME. We understand that furnace problems are more than a mere inconvenience – they can have a serious impact on the health and safety of you and your family. Our technicians are available 24-hours a day for emergency repairs. Click to schedule your repair and have peace-of-mind knowing that a licensed, certified HVAC technician will have your system up and running as quickly as possible. For 24-hour emergency furnace repair service, call 1-888-243-4663.
In 1906, Stuart W. Cramer of Charlotte was exploring ways to add moisture to the air in his textile mill. Cramer coined the term "air conditioning", using it in a patent claim he filed that year as an analogue to "water conditioning", then a well-known process for making textiles easier to process. He combined moisture with ventilation to "condition" and change the air in the factories, controlling the humidity so necessary in textile plants. Willis Carrier adopted the term and incorporated it into the name of his company.[10]
When the time comes to schedule furnace repairs, you want a team you can trust. Keeping your home warm and comfortable is important for you and your family, which is why you should rely on the highly-trained team of technicians at Horizon Services. Our techs undergo at least 150 hours of technical training every year and are up-to-date on the latest, most advanced techniques in the trade. We also background-check all of our employees to ensure your complete comfort and safety. When you call on us for furnace repair, we will arrive on-time and on schedule, ready to resolve the issue as quickly as possible.
It’s a rare occasion for a problem to arise with your heating or cooling equipment at a convenient time. In fact, we’re not even certain such a time exists! That’s why the team at HVAC & Plumbing Unlimited stands ready to provide complete emergency heating and cooling repairs. No matter the time of day or the day itself, we can be on the way and ready to provide prompt, cost-efficient services to our Alexandria clients.*
At Aire Serv, we’re on call 24/7 to offer air conditioner repair when you need it most. We charge by the job, not by the hour, and there’s never an overtime charge. We explain all your options before starting repairs so you can decide what’s best for you. Our air conditioner repair experts are licensed and insured, and we guarantee our work the first time around. Since we service and repair all equipment brands, you can put your full confidence in us to professionally complete your AC repair.
In hot weather, air conditioning can prevent heat stroke, dehydration from excessive sweating and other problems related to hyperthermia. Heat waves are the most lethal type of weather phenomenon in developed countries. Air conditioning (including filtration, humidification, cooling and disinfection) can be used to provide a clean, safe, hypoallergenic atmosphere in hospital operating rooms and other environments where proper atmosphere is critical to patient safety and well-being. It is sometimes recommended for home use by people with allergies.
Whether it’s a sticky day in July and you need an AC repair, or your employees are having trouble breathing because of stagnant indoor air, you can rely on HI-VAC Air Conditioning Service to quickly resolve your problem. We are the go-to source for air conditioning services in Plantation, Miramar, Pembroke Pines, Weston, Coral Springs, Sunrise, FL and the surrounding area. Give us a call today to learn how we can improve your indoor comfort. 

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.
Mr. Plumber provides fast, expert plumbing service to Smyrna, GA and is here for you with 24 hour emergency plumbing service. Our licensed and certified plumbers can tackle all your plumbing jobs including sink & faucet repair, toilet repair & replacement, water line repair & replacement, drain cleaning, bathtubs & shower installation and repair, water heater installation, sewer repair, backflow prevention and more. Our professional plumbers will respect your time, home and business. You approve the price before we perform our plumbing work and your satisfaction is guaranteed! Give us a call today for:
Since the 1980s, manufacturers of HVAC equipment have been making an effort to make the systems they manufacture more efficient. This was originally driven by rising energy costs, and has more recently been driven by increased awareness of environmental issues. Additionally, improvements to the HVAC system efficiency can also help increase occupant health and productivity.[24] In the US, the EPA has imposed tighter restrictions over the years. There are several methods for making HVAC systems more efficient.
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]

You can usually slip the belt on the motor’s (smaller) pulley first and then start it on the blower pulley. Rotate the blower pulley by hand, holding the belt in place but keeping your fingers from getting caught between the belt and the pulley. The belt should slip right into place. If it seems to be too tight or difficult to set in place, it may be necessary to adjust the motor mount to provide more slack.


Shortly thereafter, the first private home to have air conditioning was built in Minneapolis in 1914, owned by Charles Gates.[11] Realizing that air conditioning would one day be a standard feature of private homes, particularly in regions with warmer climate, David St. Pierre DuBose (1898-1994) designed a network of ductwork and vents for his home Meadowmont, all disguised behind intricate and attractive Georgian-style open moldings.[when?] This building is believed to be one of the first private homes in the United States equipped for central air conditioning.[12]

If your home is not heated using forced air, chances are a boiler will make sure you stay warm during cold nights. A hot water system delivers hot water through a network of pipes that run to every room in your house. The heating effect gets maximized through radiators. The most common issues with hot water heating tend to be not be major, but small problems that add up over time. Mineral deposits within the water tank, a pilot light malfunction, or an issue with a radiator itself can require professional repair. On average, you will pay between $183 and $582 for these problems. The exact amount will depend on the exact problem, as described in our boiler repair cost guide.


About us: Vredevoogd Heating & Cooling has been in business since 1964. As a financially stable company known for its reliable expertise and first-rate customer care, Vredevoogd Heating & Cooling is a company you can trust. Moreover, when you do business with a stable business like Vredevoogd Heating & Cooling, you have the peace of mind of knowing that your warranties are solidly backed by a company that intends to remain in business for another 50+ years and beyond. Don’t trust your essential home systems and investment to any fly-by-night company. Our best practices ensure that we will be here to meet our customer’s HVAC needs for decades to come. Vredevoogd Heating & Cooling founder Dennis Vredevoogd set the high standards by which the company continues to pride itself for. Today, the company continues to be family owned and operated by the founder’s sons, Michael and Thomas, who are committed to maintaining the company’s high standards and complementing them with the innovative technical know-how needed to service today’s advanced HVAC systems.

It’s a rare occasion for a problem to arise with your heating or cooling equipment at a convenient time. In fact, we’re not even certain such a time exists! That’s why the team at HVAC & Plumbing Unlimited stands ready to provide complete emergency heating and cooling repairs. No matter the time of day or the day itself, we can be on the way and ready to provide prompt, cost-efficient services to our Alexandria clients.* 

Vredevoogd Heating & Cooling invites you to research our good name. Read customer testimonials and call to discuss your service needs with our staff at any time. We provide service with minimal interruption to your home. We perform careful diagnostics and apply expert fixes for all your service needs. Because your HVAC system is essential to your home and a major investment, we encourage you to contact us for professional installation. We have 54 years of experience fueling our HVAC know how. Don’t trust your heating and cooling needs to just anyone. Let Vredevoogd Heating & Cooling Grand Rapids MI handle all your HVAC maintenance and installation needs.
Ventilation is the process of changing or replacing air in any space to control temperature or remove any combination of moisture, odors, smoke, heat, dust, airborne bacteria, or carbon dioxide, and to replenish oxygen. Ventilation includes both the exchange of air with the outside as well as circulation of air within the building. It is one of the most important factors for maintaining acceptable indoor air quality in buildings. Methods for ventilating a building may be divided into mechanical/forced and natural types.[16]
Air conditioning and refrigeration are provided through the removal of heat. Heat can be removed through radiation, convection, or conduction. Refrigeration conduction media such as water, air, ice, and chemicals are referred to as refrigerants. A refrigerant is employed either in a heat pump system in which a compressor is used to drive thermodynamic refrigeration cycle, or in a free cooling system which uses pumps to circulate a cool refrigerant (typically water or a glycol mix).
We want to compliment your fine sales and installation team. They are outstanding. Carlos, your sales rep., was highly informative. We reviewed our needs and we ultimately chose the Trane XV-18 variable speed system. Carlos did not try to up sell us with things that we did not need but he did help us choose the correct upgraded filter and UV light that we wanted. We told Carlos that our research indicated that the quality of the installation of the unit was at least as important as the unit itself, and Carlos agreed. Carlos pointed out that new proper sized duct work and copper wiring would be required for a correct installation, and that we needed to add two more returns. We asked if more returns were needed and Carlos said that would not be cost effective. That was great to hear. Carlos assured us that the installation team of Willie and Gary, both lead installers, would be used. They were both superb. They came on time and worked for 12 and 1/2 hours. It was a 93 degree day so the heat in the attic was intense. We kept telling them to take a break but they continued to work up there in what must have been 130+ temperatures. They were amazing! They were neat and cleaned up any mess they made. They patiently answered all of our many questions and gave us helpful tips. They were truly professional in all respects. We also note that Stacy, Angie and Karen of your office staff were each courteous, accommodating and efficient. They helped things to go smoothly. Carlos, Gary, Stacy, Angie, Willie and Karen are each great assets to your company. We would be comfortable recommending that team of people to anyone! Ken and Kathy Luban
Our air conditioner repair trucks are fully stocked with air conditioning repair parts and our highly trained air conditioning technicians and installation teams can repair or install a central air conditioning system right the first time. No job is too big or small; whether you need air conditioner repair work for a single unit or multiple units; you’ll get speedy, high-quality service that you can depend on. Our reliable service is the main reason so many consider us to be the best AC repair company in Houston TX! Call us now at 713-766-3605713-766-3605 to schedule an appointment.
Inspect your furnace thermostat by first making sure that it’s turned on. Also, ensure that the thermostat switch is turned to “heat” and not “cool”. If your furnace will still not start with the thermostat on, try adjusting the temperature settings to a few degrees higher. Inspect any visible wires for breaks or splits, and make sure your thermostat batteries are not dead. Do not touch any open wires; contact a professional.

Most modern air-conditioning systems feature a dehumidification cycle during which the compressor runs while the fan is slowed as much as possible[citation needed] to reduce the evaporator temperature and therefore condense more water. When the temperature falls below a threshold, both the fan and compressor are shut off to mitigate further temperature drops;[clarification needed] this prevents moisture on the evaporator from being blown back into the room.[citation needed] When the temperature rises again,[clarification needed] the compressor restarts and the fan returns to low speed.


Furnaces and thermostats are not mix-and-match appliances. Using the wrong type of thermostat with a furnace will cause operating problems and can be dangerous. Although thermostats look similar, they are designed very differently. There are numerous types of heating systems and thermostat systems and they need to be coordinated for safe and proper operation. There are three types of thermostat systems used today: millivoltage, low voltage, and line voltage.​
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]
Variable-speed technology allows more energy saving potential and improved comfort levels throughout the home.  The ability of the system to automatically adjust speeds according to the needs of the home ensures the right amount of comfort control, right when you need it.  Outside temperatures rarely, if ever, require your HVAC system to operate at 100% capacity.  Variable-speed units determine optimal cooling needs and vary speeds in increments between 40% and 100%.  Not only does this tailor comfort, but by running at lower speeds and consuming less power, you’ll save a significant amount off monthly utility expenses.

Designed to improve manufacturing process control in a printing plant, Carrier's invention controlled not only temperature but also humidity. Carrier used his knowledge of the heating of objects with steam and reversed the process. Instead of sending air through hot coils, he sent it through cold coils (filled with cold water). The air was cooled, and thereby the amount of moisture in the air could be controlled, which in turn made the humidity in the room controllable. The controlled temperature and humidity helped maintain consistent paper dimensions and ink alignment. Later, Carrier's technology was applied to increase productivity in the workplace, and The Carrier Air Conditioning Company of America was formed to meet rising demand. Over time, air conditioning came to be used to improve comfort in homes and automobiles as well. Residential sales expanded dramatically in the 1950s.[citation needed]

The most recognized standards for HVAC design are based on ASHRAE data. The most general of four volumes of the ASHRAE Handbook is Fundamentals; it includes heating and cooling calculations. Each volume of the ASHRAE Handbook is updated every four years. The design professional must consult ASHRAE data for the standards of design and care as the typical building codes provide little to no information on HVAC design practices; codes such as the UMC and IMC do include much detail on installation requirements, however. Other useful reference materials include items from SMACNA, ACGIH, and technical trade journals.


Poorly maintained water cooling towers can promote the growth and spread of microorganisms,[56] such as Legionella pneumophila, the infectious agent responsible for Legionnaires' disease, or thermophilic actinomycetes. As long as the cooling tower is kept clean (usually by means of a chlorine treatment), these health hazards can be avoided or reduced. Excessive air conditioning can have a negative effect on skin, causing it to dry out, and can also cause dehydration.[citation needed]
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