In 1758, Benjamin Franklin and John Hadley, a chemistry professor at Cambridge University, conducted an experiment to explore the principle of evaporation as a means to rapidly cool an object. Franklin and Hadley confirmed that evaporation of highly volatile liquids (such as alcohol and ether) could be used to drive down the temperature of an object past the freezing point of water. They conducted their experiment with the bulb of a mercury thermometer as their object and with a bellows used to speed up the evaporation. They lowered the temperature of the thermometer bulb down to −14 °C (7 °F) while the ambient temperature was 18 °C (64 °F). Franklin noted that, soon after they passed the freezing point of water 0 °C (32 °F), a thin film of ice formed on the surface of the thermometer's bulb and that the ice mass was about 6 mm (1⁄4 in) thick when they stopped the experiment upon reaching −14 °C (7 °F). Franklin concluded: "From this experiment one may see the possibility of freezing a man to death on a warm summer's day."[9]

The condensed, pressurized, and still usually somewhat hot liquid refrigerant is next routed through an expansion valve (often nothing more than a pinhole in the system's copper tubing) where it undergoes an abrupt reduction in pressure. That pressure reduction results in flash evaporation of a part of the liquid refrigerant, greatly lowering its temperature. The cold refrigerant is then routed through the evaporator. A fan blows the interior warm air (which is to be cooled) across the evaporator, causing the liquid part of the cold refrigerant mixture to evaporate as well, further lowering the temperature. The warm air is therefore cooled and is pumped by an exhaust fan/ blower into the room. To complete the refrigeration cycle, the refrigerant vapor is routed back into the compressor. In order for the process to have any efficiency, the cooling/evaporative portion of the system must be separated by some kind of physical barrier from the heating/condensing portion, and each portion must have its own fan to circulate its own "kind" of air (either the hot air or the cool air).
Air conditioning (often referred to as AC, A/C, or air con)[1] is the process of removing heat and moisture from the interior of an occupied space, to improve the comfort of occupants. Air conditioning can be used in both domestic and commercial environments. This process is most commonly used to achieve a more comfortable interior environment, typically for humans and other animals; however, air conditioning is also used to cool/dehumidify rooms filled with heat-producing electronic devices, such as computer servers, power amplifiers, and even to display and store some delicate products, such as artwork.
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I had Gator install two train units a year and a half ago. They the blower motor went out on one of the units. I bought Trane because I thought I was buying quality. The warranty only covers labor for the first year. I called Gator in the morning and they were fantastic. The sent a technician out immediately and had the unit operating that day at a very reasonable price. I would recommend Gator to anyone.
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]
According to a 2015 government survey, 87% of the homes in the United States use air conditioning and 65% of those homes have central air conditioning. Most of the homes with central air conditioning have programmable thermostats, but approximately two-thirds of the homes with central air do not use this feature to make their homes more energy efficient.[57]

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.*
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.
The cost to replace your entire unit is around $4,000. That expense can range from $2,500 to $5,900, depending on the type and brand of furnace you choose. Brands particularly have an impact on that price. A Goodman electric furnace, will only cost about $2,100 for the unit and labor. On the other hand, a Trane oil furnace may cost up to $9,000 all things considered. Our Furnace Installation Cost Guide can give you a better idea on both the general cost and the differences for brands like Amana, Bryant, Coleman, and others. The brand also plays into the repair cost for your furnace. Especially the prices of individual parts can change; a York heat exchanger, for example, can cost up to $1,900, while the same component from Heil will cost as little as $400.
An improperly maintained heating and air conditioning is an inefficient heating and air conditioning system. That’s why we provide appointments for annual inspections with our licensed technicians. It’s our goal to make sure that your home is as comfortable and energy-efficient as possible. For inspections, repairs, and service, contact BGE HOME for quality service.
To earn distinction as a Carrier Factory Authorized Dealer, Kabran Air Conditioning & Heating performs to exacting standards of customer dedication, business practices, and technical know-how.  Our technicians continue intensive factory training to remain current with increasingly sophisticated products and technology.  Our sales team attends Carrier University, ensuring complete product understanding and knowledgeable recommendations that perfectly suit your needs.  We maintain proper licensing, insurance and liability coverage, and fulfill warranty obligations in a timely manner.  By becoming experts in the state-of-the-art heating and cooling systems we install, accurate sizing, precision implementation, and long-term value is standard operating procedure at Kabran Air Conditioning & Heating.
In 1992, a non-governmental organization, Greenpeace, was spurred by corporate executive policies and requested that a European lab find substitute refrigerants. This led to two alternatives, one a blend of propane (R290) and isobutane (R600a), and one of pure isobutane.[18][22] Industry resisted change in Europe until 1993, and in the U.S. until 2011, despite some supportive steps in 2004 and 2008 (see Refrigerant Development above).[27][68]
You might guess it from the name: the heat exchanger is the part of your furnace that actually heats the air your blower motor pushes through the furnace. It consists of a chamber in which the heat energy produced by natural or propane gas is transferred to the forced air. At the same time, this part also includes a vent through which the gases themselves are safely removed from the unit and the air that enters your home. Because of these gases, a problem with your heat exchanger needs to be dealt with promptly. Over time, cracks in the exchanger can result in carbon monoxide leaks. Taking care of the problem once again means understanding the existence of a range: repairing your heat exchanger can cost as little as $100, but a full replacement may cost up to $1,200.
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).
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.
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.
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]
The 2nd-century Chinese mechanical engineer and inventor Ding Huan of the Han Dynasty invented a rotary fan for air conditioning, with seven wheels 3 m (10 ft) in diameter and manually powered by prisoners of the time.[6] In 747, Emperor Xuanzong (r. 712–762) of the Tang Dynasty (618–907) had the Cool Hall (Liang Dian 涼殿) built in the imperial palace, which the Tang Yulin describes as having water-powered fan wheels for air conditioning as well as rising jet streams of water from fountains. During the subsequent Song Dynasty (960–1279), written sources mentioned the air conditioning rotary fan as even more widely used.[7]

A pinging or popping sound coming from the duct work can come from thermal expansion—the ductwork expanding and contracting as it heats and cools.  Or, air blowing past a loose flap of metal can make the sound. Track along the duct runs, listening for the sound. If you locate it, make a small dent in the sheet metal to provide a more rigid surface that’s less likely to move as it heats and cools.

Replacing a capacitor is easy. Just take a photo of the wires before disconnecting anything (you may need a reference later on). Then discharge the stored energy in the old capacitor (Photo 4). Use needle-nose pliers to pluck one wire at a time from the old capacitor and snap it onto the corresponding tab of the new capacitor. The female crimp connectors should snap tightly onto the capacitor tabs. Wiggle each connector to see if it’s tight. If it’s not, remove the connector and bend the rounded edges of it so it makes a tighter fit on the tab. When you’ve swapped all the wires, secure the new capacitor (Photo 5).