The performance of vapor compression refrigeration cycles[24] is limited by thermodynamics. These air conditioning and heat pump devices move heat rather than convert it from one form to another, so thermal efficiencies do not appropriately describe the performance of these devices. The Coefficient-of-Performance (COP) measures performance, but this dimensionless measure has not been adopted. Instead, the Energy Efficiency Ratio (EER) has traditionally been used to characterize the performance of many HVAC systems. EER is the Energy Efficiency Ratio based on a 35 °C (95 °F) outdoor temperature. To more accurately describe the performance of air conditioning equipment over a typical cooling season a modified version of the EER, the Seasonal Energy Efficiency Ratio (SEER), or in Europe the ESEER, is used. SEER ratings are based on seasonal temperature averages instead of a constant 35 °C (95 °F) outdoor temperature. The current industry minimum SEER rating is 14 SEER.[25]
Headquartered in Portsmouth, Virginia, Air Conditioning Specialists was established in 1997 and is a fully licensed, insured and experienced heating and cooling company. We strive to provide our customers with the quickest, most efficient HVAC service and installation. Our workmanship, along with the highest quality of home and business products available, ensures the dependable performance of your HVAC system and your family’s comfort year after year. Our staff welcomes the opportunity to serve you, and looks forward to building a long-term relationship. Our success is dependent upon 100% customer satisfaction and the referrals we receive from our many satisfied customers.
Baker Brothers has the best HVAC technicians in the business that can service and repair your HVAC units whenever they have issues. They specialize in everything from condensers, coils, air ducts, air filtration to complete HVAC unit replacements and HVAC installations with the best warranties in Dallas / Fort Worth. Our licensed and trained HVAC professionals are experts in the services you need to get your HVAC system up and running again. Our customers can count on us for quick and efficient air conditioning services and repairs in the DFW metroplex. Our friendly customer service and expert technicians are the main reasons why so many of our customers consider us to be the best AC service company in the Dallas area!
"Jim did a great job. His price was $1300 cheaper on replacing both the attic and outside units (everything new). What I liked about him is that he was not pushing services. Although, he assessed and pointed it out everything that needed to be fixed, at the same time, he was sharing how I could do the work myself if I wanted to save the money. I really liked that. Final work was a Trane- 4 Ton, 14 Seer Heat-Pump System with 1year warranty on labor and the 10 year parts from the Trane. It works great so far. I had a 2.5 ton old ac that even when it worked well would take hours to cool down the house. No kidding, now it cools the house from 76 to 72 in 15 minutes. After using thumbtack for a while, I realized that there are good workers that will do the job for a lot cheaper. You just need to be patient and do the estimates with all the contractors that send you messages. Oh, and please, rely on the reviews. I would definably recommend 911 AC/services !!! Great job Jim!"

Heat pipe heat exchangers or run-around coils perform a similar function when humidity control is required. Two heat exchanger are placed in the air stream, one upstream of the cooling coil and the other downstream of the cooling coil. These heat exchangers are connected together with piping. A heat transfer fluid, whether it be water or refrigerant, is either pumped or gravity fed from one heat exchanger to the other. The heat exchanger down stream of the cooling coil (re-heat coil) cools the liquid medium inside the heat exchanger and heats the air passing over the heat exchanger. The cold liquid inside the heat exchanger is moved to the heat exchanger upstream of the cooling coil (pre-cool coil) where it pre-cools the air passing over the heat exchanger and warms the liquid passing through the heat exchanger. The affect of a heat pipe or run-around coil is to reduce the sensible heat capacity of the AC system. The latent capacity of the AC system increases if direct-expansion equipment is used or remains relatively constant if chilled water equipment is used. Since the sensible capacity of the AC system has been reduced, the system must run longer to meet the thermostat set point thereby removing more moisture.

Electronically Commutated (EC) fans use brushless DC motors which include in-built electronics to convert the AC supply to DC without the need for a separate DC supply. EC fans provide a more efficient (up to 30%) means of airflow through Precision Air Conditioning (PAC) units with the additional benefit of variable speed control via an output signal from the unit controller. Also see EC Fan upgrades.
Rheem's RRNL features a scroll compressor with fewer moving parts and less noise than traditional reciprocating compressors. A louvered compressor compartment protects the compressor from the elements and from debris that can shorten the life of the compressor. The Classic series continues to be one of their best sellers, with the addition of the Comfort Alert diagnostics module integrated to assist technicians in the event your system needs repair. 2-5 tons, 13 SEER, 80% AFUE.
Welzig Heating & Air is on call, 24 hours a day, 365 days, making sure that the skilled assistance you need is always available.   There’s no need to struggle with decreased performance from your air conditioner.   Even small aggravations, such as elevated sound levels, strange smells, or longer running times, are warning signs of larger issues and usually add up to higher running costs.   When you trust your cooling equipment to Welzig Heating & Air, we work to not only resolve pressing issues. but ensure reliability, efficiency, and longevity.   A thorough inspection often protects against degraded air quality, property damage, and premature system failure.   We work on all makes and models of air conditioners, and with every repair we tackle, our team of dedicated technicians earn your satisfaction.   Through exemplary customer service, ethical business practices, and exacting standards, Welzig Heating & Air provides superior solutions to homeowners across Boulder, Longmont, Louisville, Lafayette, CO & more.
At the first sign your HVAC system is not working properly, you should call us to schedule an appointment with one of our NATE-certified technicians. The longer you wait to have that strange noise or smell checked out, it could lead to higher repair bills or HVAC system failure. Don't wait until it is too late and you are without your heating or cooling equipment. Catching the problem early on could save you hundreds of dollars in repair bills.
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.
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, on 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.
In addition, if water is condensed in the room, the amount of heat previously needed to evaporate that water also is re-released in the room (the latent heat of vaporization). The dehumidification process is the inverse of adding water to the room with an evaporative cooler, and instead releases heat. Therefore, an in-room dehumidifier always will warm the room and reduce the relative humidity indirectly, as well as reducing the humidity directly by condensing and removing water.
Clean the condenser fan blades before the start of the cooling season. Brush any dust or debris off gently and then uncover the condenser coils, gently cleaning the dirty side. Then wrap the motor and other electrical components in plastic bags and gently spray from the inside with a hose. Now check the base pan under the unit and clear it out of any debris that has gathered.

These factors are included in a "Manual J" calculation. Contractors who make these calculations before recommending a size can take a couple of hours collecting the information and making the calculation. If your contractor doesn't do it, there are services that will do it for around $99. If you're feeling particularly on the ball, there are also free online calculators.


An energy recovery ventilator: This component helps improve the air inside your home by swapping it out with fresh air from the outside. During the winter months when houses are closed up to keep out the cold, the air inside becomes a handy way for colds and flu to infect an entire family. By circulating outside air inside, the health of your family will have a better chance.
Locally owned and family operated, M and M, Heating & Cooling, Plumbing & Electrical customizes solutions to perfectly fit your requirements and lifestyle. We specialize in a wide range of services including plumbing, water heating, indoor air quality, and residential and commercial temperature control. Our team of highly trained and certified technicians are fully licensed and insured, adhere to strict service procedures, and meet exacting standards of quality. Call on M and M, Heating & Cooling, Plumbing & Electrical at (720) 443-6119 for dedicated service throughout Longmont, CO & surrounding areas, and have confidence in a rewarding experience and long-term results. With over eighteen years of satisfied customers, we take great pride in a job done right.

They are also often harder to install. A proper location on the roof must be selected that can support the weight of the unit. Then a platform must be built and a drain pipe for the unit must be run along the roof to avoid problems with mold and corrosion. A crane must be used to lift the unit onto the roof while a team guides it into place and hooks it up.
Vredevoogd Heating & Cooling Grand Rapids employs more than 80 people who are proud to work under the Vredevoogd Heating & Cooling banner. Each team member shares our company values for service excellence. All of our employees are intensely screened and background checked so that you have peace of mind when they enter your home. Moreover, our technicians are certified to work in the HVAC industry and provide the level of expertise that our customers expect from Vredevoogd Heating & Cooling. We back our technicians’ work and continue to make training a priority so that all of our techs are familiar with the latest HVAC models and advances. Our customers deserve the best, so the best is what we deliver to each and every job.
Split ACs are used in larger application areas than window ACs. The split AC focuses on splitting the cold from the hot side of the system. The cold side has the cold coil and the expansion valve. This is usually placed inside a furnace or any other form of air handler. The handler blows air over the coil and the cooled air is distributed to various rooms in the building through the air ducts.
Service Experts Heating and Air Conditioning was founded with the determination of offering customers with the top of the line heating and cooling practices in the industry. Since it started, Service Experts in Raleigh has been committed to our area, offering the finest HVAC (Heating, Ventilation, Air Conditioning) products and services in the area. If you are interested in more details about your regional HVAC leaders, simply dial us at 919-578-4329 or set up an appointment with us using our online form.
For more than sixty years, Nerthling's Heating and Air Conditioning has continued a tradition of superior customer service across Erie County, including Erie, Millcreek and Fairview.  Family owned and operated, we treat you, your home, and your comfort the way we would like to be treated.  This commitment to integrity extends to every service and product we provide.  Our goal is to deliver the highest rewards for your investment, whether you require installation, maintenance, or repair.  We offer a wide range of styles and sizes of equipment, services, and resources to help you achieve your goals for temperature control, air quality, and energy savings.
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.
Filtration systems -- A second-stage filter is sometimes inserted & used to remove particulates such as pets, smoking or cooking, as well as other odors, gases, and VOCs (volatile organic compounds). A HEPA filter is also available to remove spores, pollens, bacteria and lung-damaging particles. There are also systems that use ultraviolet (UV) light to protect against bacteria and germs.
The manufacture and use of CFCs has been banned or severely restricted due to concerns about ozone depletion (see also Montreal Protocol).[63][64] In light of these environmental concerns, beginning on November 14, 1994, the U.S. Environmental Protection Agency has restricted the sale, possession and use of refrigerant to only licensed technicians, per rules under sections 608 and 609 of the Clean Air Act.[65]

In 1820, English scientist and inventor Michael Faraday discovered that compressing and liquefying ammonia could chill air when the liquefied ammonia was allowed to evaporate. In 1842, Florida physician John Gorrie used compressor technology to create ice, which he used to cool air for his patients in his hospital in Apalachicola, Florida. He hoped to eventually use his ice-making machine to regulate the temperature of buildings. He even envisioned centralized air conditioning that could cool entire cities. Though his prototype leaked and performed irregularly, Gorrie was granted a patent in 1851 for his ice-making machine. Though his process improved the artificial production of ice, his hopes for its success vanished soon afterwards when his chief financial backer died and Gorrie did not get the money he needed to develop the machine. According to his biographer, Vivian M. Sherlock, he blamed the "Ice King", Frederic Tudor, for his failure, suspecting that Tudor had launched a smear campaign against his invention. Dr. Gorrie died impoverished in 1855, and the dream of commonplace air conditioning went away for 50 years.[citation needed]
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.
Over the Labor Day weekend our hot water heater decided it was time to say good bye. Since we had our fall check the week before, we called Nerthlings. I cannot say enough good things about how this situation was handled. The technician, Dwain, was knowledgeable, friendly, and quite helpful without being pushy. Our questions were answered clearly. I am never made to feel that this is something...
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.
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.

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.


Modern air conditioning systems are not designed to draw air into the room from the outside, they only recirculate the increasingly cool air on the inside. Because this inside air always has some amount of moisture suspended in it, the cooling portion of the process always causes ambient warm water vapor to condense on the cooling coils and to drip from them down onto a catch tray at the bottom of the unit from which it must then be routed outside, usually through a drain hole. As this moisture has no dissolved minerals in it, it will not cause mineral buildup on the coils. This will happen even if the ambient humidity level is low. If ice begins to form on the evaporative fins, it will reduce circulation efficiency and cause the development of more ice, etc. A clean and strong circulatory fan can help prevent this, as will raising the target cool temperature of the unit's thermostat to a point that the compressor is allowed to turn off occasionally. A failing thermistor may also cause this problem. Refrigerators without a defrost cycle may have this same issue. Dust can also cause the fins to begin blocking air flow with the same undesirable result: ice.

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.[56]
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.[21] In the US, the EPA has imposed tighter restrictions over the years. There are several methods for making HVAC systems more efficient.
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