Heating, ventilation, and air conditioning (HVAC[1]) is the technology of indoor and vehicular environmental comfort. Its goal is to provide thermal comfort and acceptable indoor air quality. HVAC system design is a subdiscipline of mechanical engineering, based on the principles of thermodynamics, fluid mechanics and heat transfer. "Refrigeration" is sometimes added to the field's abbreviation, as HVAC&R or HVACR or "ventilation" is dropped, as in HACR (as in the designation of HACR-rated circuit breakers).
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.
Central, "all-air" air-conditioning systems (or package systems) with a combined outdoor condenser/evaporator unit are often installed in North American residences, offices, and public buildings, but are difficult to retrofit (install in a building that was not designed to receive it) because of the bulky air ducts required. (Minisplit ductless systems are used in these situations.) Outside of North America, packaged systems are only used in limited applications involving large indoor space such as stadiums, theatres or exhibition halls.
Whether you are in need of new installation, system replacement, seasonal maintenance, or prompt repair, M and M, Heating & Cooling, Plumbing & Electrical lives up to your highest expectations for quality, pricing, reliability, and quick turnaround on all projects.  And our commitment isn’t limited to regular business hours.  We’re always available when you need us, providing 24 hour Emergency Service across Longmont, Dacono, Frederick, Firestone, Mead, Erie & Johnstown, CO.  Trust the #1 Rated and Certified – A/C, Heating, and Plumbing Experts.
Air conditioners often use a fan to distribute the conditioned air to an occupied space such as a building or a car to improve thermal comfort and indoor air quality. Electric refrigerant-based AC units range from small units that can cool a small bedroom, which can be carried by a single adult, to massive units installed on the roof of office towers that can cool an entire building. The cooling is typically achieved through a refrigeration cycle, but sometimes evaporation or free cooling is used. Air conditioning systems can also be made based on desiccants (chemicals which remove moisture from the air) and subterraneous pipes that can distribute the heated refrigerant to the ground for cooling.[2]

Central, "all-air" air-conditioning systems (or package systems) with a combined outdoor condenser/evaporator unit are often installed in North American residences, offices, and public buildings, but are difficult to retrofit (install in a building that was not designed to receive it) because of the bulky air ducts required. (Minisplit ductless systems are used in these situations.) Outside of North America, packaged systems are only used in limited applications involving large indoor space such as stadiums, theatres or exhibition halls.


Refrigeration air conditioning equipment usually reduces the absolute humidity of the air processed by the system. The relatively cold (below the dewpoint) evaporator coil condenses water vapor from the processed air, much like an ice-cold drink will condense water on the outside of a glass. Therefore, water vapor is removed from the cooled air and the relative humidity in the room is lowered. The water is usually sent to a drain or may simply drip onto the ground outdoors. The heat is ejected by the air conditioners condenser, which is located outside of the area being cooled.
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.
When central air conditioning service fails during a heat spell, you may have to wait days for an HVAC repair technician or a 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.
If your furnace’s motor runs but the blower doesn’t move air, the belt that connects the two probably has broken. Replacing it is an easy fix. First, turn off all power to the unit and turn off the gas at the gas valve that serves the furnace. Remove the door on the front of the furnace cabinet to give you access to the blower (it might be on a slide-out drawer.) Check the number stamped on the belt and get an exact replacement from a home center or heating supply outlet.
Though Harrison had commercial success establishing a second ice company back in Sydney in 1860, he later entered the debate over how to compete against the American advantage of ice-refrigerated beef sales to the United Kingdom. He wrote: "Fresh meat frozen and packed as if for a voyage, so that the refrigerating process may be continued for any required period", and in 1873 prepared the sailing ship Norfolk for an experimental beef shipment to the United Kingdom. His choice of a cold room system instead of installing a refrigeration system upon the ship itself proved disastrous when the ice was consumed faster than expected.[citation needed]
HVAC is an important part of residential structures such as single family homes, apartment buildings, hotels and senior living facilities, medium to large industrial and office buildings such as skyscrapers and hospitals, vehicles such as cars, trains, airplanes, ships and submarines, and in marine environments, where safe and healthy building conditions are regulated with respect to temperature and humidity, using fresh air from outdoors.
When natural gas, propane or heating oil are burned in a furnace, the resulting hot combustion gasses by burning natural gas, propane or heating oil circulate through a heat exchanger. The heat exchanger will, in turn, release that heat to be circulated by the furnace’s blower. The flue gas then travels through the flue vent, which carries the gas outside of the home. When a heat exchanger is cracked, it generally will require a complete system replacement. That is one of the reasons why we highly recommend annual preventive maintenance on your home’s furnace – this preventative furnace inspection and maintenance can greatly prolong the life of your home heating system.
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).
If you’re looking to maintain, replace, or repair your home or business’s air conditioning system, “Make the Precision Decision”™ and give us a call. We are available 24/7 for all your emergency service needs. Our service area includes Litchfield Park, Mesa, Avondale, Peoria, Phoenix, Chandler, Scottsdale, Sun Lakes, Gilbert, Surprise, Glendale, Tempe, Goodyear and surrounding areas.
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.
The compressor-based refrigerant systems are air-cooled, meaning they use air to exchange heat, in the same way as a car radiator or typical household air conditioner does. Such a system dehumidifies the air as it cools it. It collects water condensed from the cooled air and produces hot air which must be vented outside the cooled area; doing so transfers heat from the air in the cooled area to the outside air.
I was disappointed with the pressure of a tub and shower that were plumbed with 1/2 supply lines (2nd floor). Could be low pressure from the street, but I want to replace with 5/8. Plus, I'd like to have 2 back to back showers, one inside and one outside. So, I had intended to bring a 1 supply to both, then branch up to valves and shower head with 5/8. Finally, I thought pressure from the street was typically 55 to 70 psi and I am concerned if pvc can take that.Any thoughts?
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.

There was an unidentified beeping sound which I thought was coming from my indoor HVAC unit. The technician patiently spoke to me over the phone and we discovered that it was not the HVAC that was making the noise. The technician was extraordinarily helpful and polite as we spoke and he saved me a few hundred dollars since he helped me over the phone and didn't have to make an emergency visit. HVAC Unlimited is our "go to" company for all our heating and cooling needs!
The HVAC industry is a worldwide enterprise, with roles including operation and maintenance, system design and construction, equipment manufacturing and sales, and in education and research. The HVAC industry was historically regulated by the manufacturers of HVAC equipment, but regulating and standards organizations such as HARDI, ASHRAE, SMACNA, ACCA, Uniform Mechanical Code, International Mechanical Code, and AMCA have been established to support the industry and encourage high standards and achievement.
American design standards are legislated in the Uniform Mechanical Code or International Mechanical Code. In certain states, counties, or cities, either of these codes may be adopted and amended via various legislative processes. These codes are updated and published by the International Association of Plumbing and Mechanical Officials (IAPMO) or the International Code Council (ICC) respectively, on a 3-year code development cycle. Typically, local building permit departments are charged with enforcement of these standards on private and certain public properties.
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]
High-efficiency condensing furnaces (90% AFUE and above) are a bit more complex than conventional furnaces. The main differences between a conventional and condensing furnace are the heat exchanger technology used to extract heat from the combustion process and the method used to exhaust the combustion gases. In these ways, the furnaces are very different. The condensing furnace does not have a significantly more efficient combustion process than does a conventional furnace; both use gas burners with electronic ignition. The difference lies in that the condensing furnace has a more efficient heat extraction process after combustion.
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]
SEER is related to the coefficient of performance (COP) commonly used in thermodynamics and also to the Energy Efficiency Ratio (EER). The EER is the efficiency rating for the equipment at a particular pair of external and internal temperatures, while SEER is calculated over a whole range of external temperatures (i.e., the temperature distribution for the geographical location of the SEER test). SEER is unusual in that it is composed of an Imperial unit divided by an SI unit. The COP is a ratio with the same metric units of energy (joules) in both the numerator and denominator. They cancel out, leaving a dimensionless quantity. Formulas for the approximate conversion between SEER and EER or COP are available.[34]
The blower assembly is located between your main furnace and the cold air return. The blower is responsible for pulling air from your home and then sending it through the furnace and the heat exchanger. The air gets circulated throughout the home via the duct work. The furnace’s air filter is contained within the blower compartment. Regular-style filters should be replaced or cleaned each month.

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. 

Free cooling systems can have very high efficiencies, and are sometimes combined with seasonal thermal energy storage so that the cold of winter can be used for summer air conditioning. Common storage mediums are deep aquifers or a natural underground rock mass accessed via a cluster of small-diameter, heat-exchanger-equipped boreholes. Some systems with small storages are hybrids, using free cooling early in the cooling season, and later employing a heat pump to chill the circulation coming from the storage. The heat pump is added-in because the storage acts as a heat sink when the system is in cooling (as opposed to charging) mode, causing the temperature to gradually increase during the cooling season.
Whole-house fans have helped cool homes for a century. The basic design is simple: An attic-mounted fan pushes hot air out through attic vents and draws cooler, outside air in through open doors and windows. This rapid air exchange—large fans can purge a house of hot air in two to three minutes—not only removes built-up heat but also creates a pleasant breeze.
Modern refrigerants have been developed to be more environmentally safe than many of the early chlorofluorocarbon-based refrigerants used in the early- and mid-twentieth century. These include HCFCs (R-22, as used in most U.S. homes before 2011) and HFCs (R-134a, used in most cars) have replaced most CFC use. HCFCs, in turn, are supposed to have been in the process of being phased out under the Montreal Protocol and replaced by HFCs such as R-410A, which lack chlorine.[14] HFCs, however, contribute to climate change problems. Moreover, policy and political influence by corporate executives resisted change.[15][16] Corporations insisted that no alternatives to HFCs existed. The environmental organization Greenpeace provided funding to a former East German refrigerator company to research an alternative ozone- and climate-safe refrigerant in 1992. The company developed a hydrocarbon mix of isopentane and isobutane, but as a condition of the contract with Greenpeace could not patent the technology, which led to its widespread adoption by other firms.[17][18][19] Their activist marketing first in Germany led to companies like Whirlpool, Bosch, and later LG and others to incorporate the technology throughout Europe, then Asia, although the corporate executives resisted in Latin America, so that it arrived in Argentina produced by a domestic firm in 2003, and then finally with giant Bosch's production in Brazil by 2004.[20][21]
A number of other variables can influence your decision on whether to repair or replace your furnace, as well. In addition to cost and brand, consider the expected lifetime of your furnace. If it is more than 15 years old, it might make more sense to invest in a new unit even if it costs more than simply repairing the current problem. Long-term costs also play into the equation. For example, your new furnace may be more energy efficient than the current unit. Even though you will pay more for the actual installation, you might be able to make back your investment through lower energy bills. To make your decision, consult with a reliable professional on what to do. In inspecting your furnace, they will be able to make an informed recommendation that looks not just to the next year, but years into the future. That way, you can make the best possible decision for your home and budget long-term.

At HI-VAC Air Conditioning Service, we realize that it can be difficult to find an air conditioning company that you can trust. While many companies can handle AC repair, we strive to go above and beyond the basics. We are honest, reliable and guarantee professional 24/7 service from South Florida’s #1 Choice for air conditioning installation, service, maintenance and repair since 1970. When you choose HI-VAC Air Conditioning Service for your air conditioning and ventilation needs you’ll have our 100-percent satisfaction guarantee and first-rate service:
As touched on by their name, heat pumps function by transferring heat energy indoors during the winter and outdoors from your home during the summer. They're often attached to air conditioning units, using the surrounding air to transfer energy. However, geothermal heat pumps and water source heat pumps are also available. The cost to repair a heat pump, again, depends on the specific problem. Replacing a faulty thermostat may cost up to $300 including labor, while a worn or damaged defrost control board can set you back up to $600. For more details on your potential repair costs using this heating source, visit our heat pump repair cost guide.
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Our goal is to make you more comfortable in your home. When your furnace, central air conditioner, heat pump or boiler stops working and you need service, call the professionals at BGE HOME. Heating and cooling system breakdowns occur at the most inconvenient times, so rely on our certified, skilled technicians to make the repair quickly and correctly the first time.
If you live in a warmer climate, your air conditioner is likely one of the most essential pieces of equipment for your home. The best course is to perform regular routine air conditioner maintenance to ensure its smooth operation during the warmest months of the year. Annual tune-ups by a professional HVAC technician will increase the lifespan of your unit. When repairs are needed, be sure to hire a technician trained and certified in HVAC repair for best results. Following these guidelines will ensure that you are comfortable and cool through the summer season.
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