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 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.

When seeking emergency heating or cooling services you want experts that actually care about the results and your comfort. You want to choose the HVAC company in Alexandria with extensive skill and top-class tools, but you don’t want them to take advantage of your bad situation! With HVAC & Plumbing Unlimited, you never need to worry. We make it our mission to offer superior services any time you need it, and we guarantee cost-efficient solutions that restore your comfort.

Air changes per hour Bake-out Building envelope Convection Dilution Domestic energy consumption Enthalpy Fluid dynamics Gas compressor Heat pump and refrigeration cycle Heat transfer Humidity Infiltration Latent heat Noise control Outgassing Particulates Psychrometrics Sensible heat Stack effect Thermal comfort Thermal destratification Thermal mass Thermodynamics Vapour pressure of water


There is nothing worse than having your air conditioner break in the middle of a long, hot summer. You can ensure your air conditioning unit stays in working order all year long with regular service. Sometimes, however, repairs are necessary whether it’s fixing the evaporator, capacitor, or condenser or recharging the refrigerant. Most air conditioner repairs cost between $163 and $533 with most homeowners reporting that they spend about $347. If you do need a repair, here is some information to help you get it done quickly, professionally, and economically.
Although HVAC is executed in individual buildings or other enclosed spaces (like NORAD's underground headquarters), the equipment involved is in some cases an extension of a larger district heating (DH) or district cooling (DC) network, or a combined DHC network. In such cases, the operating and maintenance aspects are simplified and metering becomes necessary to bill for the energy that is consumed, and in some cases energy that is returned to the larger system. For example, at a given time one building may be utilizing chilled water for air conditioning and the warm water it returns may be used in another building for heating, or for the overall heating-portion of the DHC network (likely with energy added to boost the temperature).[4][5][6]
This information is not intended as an offer to sell, or the solicitation of an offer to buy, a franchise. It is for information purposes only. Read More Currently, the following states regulate the offer and sale of franchises: California, Hawaii, Illinois, Indiana, Maryland, Michigan, Minnesota, New York, North Dakota, Oregon, Rhode Island, South Dakota, Virginia, Washington, and Wisconsin. If you are a resident of or want to locate a franchise in one of these states, we will not offer you a franchise unless and until we have complied with applicable pre-sale registration and disclosure requirements in your state. Read Less Aire Serv is a registered trademark of Aire Serv LLC © Aire Serv | All rights reserved | All Aire Serv franchise locations are independently owned and operated.
Should you need to replace an air conditioning unit, Abacus Plumbing recommends Lennox brand of air conditioning and heating systems. Lennox systems offer the highest level of home comfort at the lowest possible cost of operation. Additionally, these systems are praised by consumer publications and meet or exceed all government standards for efficiency. Learn more about installation »

Recent Review: Had asked another company to fix furnace. Other company suggested furnace replacement to the tune of 7k. United Mech was a "second quote"; they came, they looked, they agreed the unit was older, and gave both a quote (1000 less) to replace and the suggestion that the part might be the only problem. Chose to fix not replace. Technician was clearly very familiar with repair. Second good experience with this company. First time, inquired about installing a gas stove in my house. They came, reviewed the ways to run the gas line to the kitchen. They told me it possible, explained how and then said was really too expensive to make it worth it. Unusual to have a firm talk a client out of major job. I remembered that and called them when we needed a second opinion.
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]
Air changes per hour Bake-out Building envelope Convection Dilution Domestic energy consumption Enthalpy Fluid dynamics Gas compressor Heat pump and refrigeration cycle Heat transfer Humidity Infiltration Latent heat Noise control Outgassing Particulates Psychrometrics Sensible heat Stack effect Thermal comfort Thermal destratification Thermal mass Thermodynamics Vapour pressure of water
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 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).
Contending with South Florida’s temperature extremes is easy — if you have a heating and air conditioning contractor you can trust for prompt, dependable and affordable work. For over 40 years, our family-owned and operated company has helped home and business owners with their heating and cooling needs. From air conditioning repairs to maintaining heat pumps to installing a ductless system, you can rely on HI-VAC Air Conditioning Service. We are a full-service provider of HVAC services for Plantation, Miramar, Pembroke Pines, Weston, Coral Springs, Sunrise, FL, and the surrounding area.
No one wants to be stuck in the dead of summer with a broken air conditioner, or in the cold of winter with a broken furnace or boiler. That’s why we’re available any time of day to make your emergency heating and air conditioning repair and get your system up and running as quickly as possible. We’ll show up on time, in uniform and ready to make your HVAC repair right the first time.
You shouldn’t have to spend any more time in a state of discomfort than is necessary. If you feel like your home’s HVAC isn’t operating as smoothly and efficiently as it should, or you can tell you should be getting more out of your home’s air conditioning system, call Gainesville Mechanical, Inc. for air conditioning unit repair, and we can send someone to your door anytime day or night.
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.
HVAC equipment is estimated to last about 15 to 20 years. Yet over the years, parts go out and need to be repaired. Heat sensors, exchangers, and ducts can become worn out. Air conditioning motors may need repairing from time to time. For repairs to your heating and air conditioning systems, and even general maintenance, let HomeAdvisor help. Enter your zip code and let us connect you with prescreened HVAC repair services near you.
5) Your air conditioner is short cycling. It is perfectly normal for your air conditioner to cycle on and off to maintain a set temperature throughout your home. However, if you notice that it is turning on and off more frequently than usual and the outside temperature is not particularly warmer than normal, it is possible that your unit is malfunctioning. Short cycling puts extra stress on your air conditioner, and can cause it to fail if not handled quickly. 
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.

We believe that the key to our growing business success is our front-liners. Our team is composed of highly-trained technicians, electricians, and building professionals who are dedicated to providing excellent service. They work with clients to understand their needs and provide the most suitable but cost-effective solutions to property maintenance.
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.
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.*
We relocate frequently and one of the biggest hassles of relocating to new areas is finding reputable companies that send qualified technicians to perform work when you need it, whether for annual preventative maintenance or during a house emergency. We’ve been through the process several times and always dread researching and trying new companies. This was our first HVAC call here in northern Virginia. We are in new construction and chose not to use the builder’s sub-contractor for a technician call but looked through Carrier’s website for a local business. Jeremy Garner with HVAC Unlimited responded to our service request the morning following our call. I shadowed him performing work and he was patient while I peppered him with questions. He helped expand my HVAC knowledge in order to be a better property owner of our systems. He performed the work we thought was necessary, in a timely and professional manner, and gave us options for future annual maintenance. HVAC Unlimited is definitely on our list of go-to contractors.
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