Some systems include an "economizer mode", which is sometimes called a "free-cooling mode". When economizing, the control system will open (fully or partially) the outside air damper and close (fully or partially) the return air damper. This will cause fresh, outside air to be supplied to the system. When the outside air is cooler than the demanded cool air, this will allow the demand to be met without using the mechanical supply of cooling (typically chilled water or a direct expansion "DX" unit), thus saving energy. The control system can compare the temperature of the outside air vs. return air, or it can compare the enthalpy of the air, as is frequently done in climates where humidity is more of an issue. In both cases, the outside air must be less energetic than the return air for the system to enter the economizer mode.

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%.


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.
Air conditioner equipment power in the U.S. is often described in terms of "tons of refrigeration", with each approximately equal to the cooling power of one short ton (2000 pounds or 907 kilograms) of ice melting in a 24-hour period. The value is defined as 12,000 BTU per hour, or 3517 watts.[32] Residential central air systems are usually from 1 to 5 tons (3.5 to 18 kW) in capacity.

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.


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.


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.
In the United States, HVAC engineers generally are members of the American Society of Heating, Refrigerating, and Air-Conditioning Engineers (ASHRAE), EPA Universal CFC certified (for installation and service of CFC HVAC devices), or locally engineer certified such as a Special to Chief Boilers License issued by the state or, in some jurisdictions, the city. ASHRAE is an international technical society for all individuals and organizations interested in HVAC. The Society, organized into regions, chapters, and student branches, allows exchange of HVAC knowledge and experiences for the benefit of the field's practitioners and the public. ASHRAE provides many opportunities to participate in the development of new knowledge via, for example, research and its many technical committees. These committees typically meet twice per year at the ASHRAE Annual and Winter Meetings. A popular product show, the AHR Expo, is held in conjunction with each winter meeting. The Society has approximately 50,000 members and has headquarters in Atlanta, Georgia.

I don’t normally rate a company 5 stars, because nobody is perfect, but these guys did a wonderful job. Carlos their sales person was knowledgeable and courteous. The office staff was extremely helpful and very friendly and the installers were on time and did a great job. Even the county inspector said, “Wow, these guys did a great job!” That’s the first time I’ve ever heard an inspector give his personal opinion on a job. I’m sixty one and I’ve had to have a lot of systems replace over the years. Well done everyone at Gator Air. Your the best! If your looking to replace your AC system, look no further.


Clean air delivery rate is the amount of clean air an air cleaner provides to a room or space. When determining CADR, the amount of airflow in a space is taken into account. For example, an air cleaner with a flow rate of 100 cfm (cubic feet per minute) and an efficiency of 50% has a CADR of 50 cfm. Along with CADR, filtration performance is very important when it comes to the air in our indoor environment. Filter performance depends on the size of the particle or fiber, the filter packing density and depth and also the air flow rate.[31]
The performance of vapor compression refrigeration cycles[27] 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.[28]
Hospital operating theatres, in which air is filtered to high levels to reduce infection risk and the humidity controlled to limit patient dehydration. Although temperatures are often in the comfort range, some specialist procedures, such as open heart surgery, require low temperatures (about 18 °C, 64 °F) and others, such as neonatal, relatively high temperatures (about 28 °C, 82 °F).
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.
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.
Recent Review: Frymire did a complete A/C and Furnace install on my property in May 2013.  I had 5 companies bid the job and what sold me on them was their honesty and responsiveness, as well as a fair price.  They were not the lowest, but were willing to negotiate on some unknown repair issues with my duct work, etc.  The team was punctual and very professional, taking extra pains to wear protective footwear on my hardwood floors.  The foreman on the job kept me up to speed about the install throughout the day.   They started at 9 a.m. and were finished and out by 6pm.  I recently had them return for the yearly check-up on my A/C.  The tech was efficient and very professional.  I would highly recommend their service. 
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!
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.
The selection of indoor units has one restriction: their total power should not exceed the capacity of the outdoor unit. In practice, however, it is very common to see a multi-split system with a total capacity of indoor units greater than the outdoor capacity by at least 20%. However, it is wrong to expect better performance when all indoor units are turned on at the same time, since the total capacity of the whole system is limited by the capacity of the outdoor unit. Simply put, the outdoor unit will distribute all its power to all operating indoor units in such a way that some of the rooms may not have a very comfortable temperature level. However, the calculation of the total power is not simple, since it takes into account not only the nominal power of the units, but also the cooling capacity, heating, dehumidification, humidification, venting, etc.
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. 

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]

Vacuum the fins of your AC unit clean with a soft-bristle brush. Note: they’re fragile and can easily be bent or crushed. On many units you’ll have to unscrew and lift off a metal box to get at them. Check your owner’s manual for directions and lift off the box carefully to avoid bumping the fins. Follow these other steps to safely clean your home air conditioner for better efficiency.

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.

Gas furnaces and heaters have control shutoffs to prevent gas leaks, but they are not fail-safe. If you smell gas in your house, do not turn any lights on or off, and do not try to shut off the gas leading to the furnace. Get out of the house, leaving the door open, and immediately call the gas company or the fire department to report a leak. Do not re-enter your home.
CIBSE publishes several guides to HVAC design relevant to the UK market, and also the Republic of Ireland, Australia, New Zealand and Hong Kong. These guides include various recommended design criteria and standards, some of which are cited within the UK building regulations, and therefore form a legislative requirement for major building services works. The main guides are:

It’s important to keep your furnace receives regular maintenance to ensure that it’s working properly and efficiently. Routine maintenance can also extend the life of your heating system by several years. Ask about our annual maintenance agreements that cover your plumbing, heating, and cooling systems and save you money. A furnace that has been neglected may be working too hard, which can result in inconsistent air temperatures in your Minneapolis area home. Learn more about the importance of routine maintenance on your HVAC system. 

The Chartered Institution of Building Services Engineers is a body that covers the essential Service (systems architecture) that allow buildings to operate. It includes the electrotechnical, heating, ventilating, air conditioning, refrigeration and plumbing industries. To train as a building services engineer, the academic requirements are GCSEs (A-C) / Standard Grades (1-3) in Maths and Science, which are important in measurements, planning and theory. Employers will often want a degree in a branch of engineering, such as building environment engineering, electrical engineering or mechanical engineering. To become a full member of CIBSE, and so also to be registered by the Engineering Council UK as a chartered engineer, engineers must also attain an Honours Degree and a master's degree in a relevant engineering subject.
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