A little simple math can help determine the size system you need. A rule of thumb is 20 BTUs per square foot. So, a 500 square foot room would need 10,000 BTUs to cool or warm it efficiently. This assumes that you live in a temperate region and have adequate insulation with no energy loss. In the real world, all units have some degree of energy loss. This is reflected in an HVAC system's SEER rating for cooling and AFUE rating for heating.
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]
Humidity is becoming more of a concern to building operators and owners. High indoor humidity leads to mold and mildew growth inside the building. The are several methods of controlling indoor humidity. The simplest (and most expensive) method is to connect a humidistat to an electric heater. When the humidity inside the building rises above the humidistat set point, the heater is turned on. The additional heat causes the air conditioning system to run longer and remove more moisture.

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]
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.
Get specifics. Contractors who bid on your job should calculate required cooling capacity by using a recognized method such as one found in the the ACCA’s Residential Load Calculation Manual, also called Manual J. An additional reference for assessing ductwork needs is Manual D. The calculations produce a detailed, room-by-room analysis of cooling needs. Ask for a printout of all calculations and assumptions, including ductwork design. Be leery of a contractor who bases estimates merely on house size or vague rules of thumb.
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.
Combustion gases are generated by the burners in your furnace and passed through a heat exchanger. Air from your home blows across the heat exchanger to be warmed. It is then blown through a system of ducts to distribute around your home. During warm seasons your heating system works with your central air conditioning. Air is cooled as it’s blown over your air conditioning unit’s cooling coil, often attached to the air circulating fan of the furnace, and then sent through the same air ducts throughout your home.
So the furnace went out (again). We’re probably not the people you want to be dialing, but in these circumstances, Service Experts Heating & Air Conditioning in North America should be your very first call. You don’t even have to worry how late (or early) it is – our NATE-certified technicians available at all hours, every day of the year. We’ll be there in a jiffy and get the job done fast – so you can get back to your routine and not have to even think about needing another furnace repair anytime soon.
The contactor (relay) and start/run capacitor(s) (see illustration below) fail most often and are inexpensive. So it’s a safe bet to buy and install those parts right away, especially if your air conditioning service unit is older than five years. The condenser fan motor can also fail, but it runs about $150 — hold off buying that unless you’re sure that’s the culprit.

Seasonal checks. Once a year have a licensed professional change all filters, clean and flush the coils, drain the pan and drainage system, and vacuum the blower compartments. The contractor should also check to make sure that the system is properly charged with refrigerant, that there are no leaks, and that all mechanical components are working properly.


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.

If you believe that the ac not working or you’re getting little or no cold air, check these three things first. Make sure all the registers in the house are wide open. Then be sure the furnace filter is clean. Then go outside and clean off the condenser coils (Photo 2). If several registers were closed or the filter was clogged, the reduced airflow could have caused the evaporator coil to ice up and stop cooling your home. If you’ve changed the filter and opened all the registers and you’re still not getting airflow at the registers, deice the A-coil. Move the thermostat mode switch from “Cooling” to “Off” and move the fan switch from “Auto” to “On.” Let the blower run for at least 30 minutes or until there’s good airflow at the registers. Then turn the AC back on to test it. If it works for the next 12 hours, you’ve solved the problem.
Smyrna homes and businesses have relied on Coolray for air conditioning service and installation since 1966. We can provide repair and maintenance on all makes and models of air conditioners for your home or business and offer 24 hour emergency AC repair service. We also offer a wide range of new air conditioning systems and our expert air conditioning technicians can help you select an air conditioner or heat pump that is right for your home and budget.

An air conditioner cools and dehumidifies the air as is passes over a cold coil surface. The indoor coil is an air-to-liquid heat exchanger with rows of tubes that pass the liquid through the coil. Finned surfaces connected to these tubes increase the overall surface area of the cold surface thereby increasing the heat transfer characteristics between the air passing over the coil and liquid passing through the coil. The type of liquid used depends on the system selected. Direct-expansion (DX) equipment uses refrigerant as the liquid medium. Chilled-water (CW) can also be used as a liquid medium. When the required temperature of a chilled water system is near the freezing point of water, freeze protection is added in the form of glycols or salts. Regardless of the liquid medium used, the liquid is delivered to the cooling coil at a cold temperature.


If you're in need of heat repair, furnace repair or heating repair then call the Ashburn HVAC Services family-owned and operated HVAC contractor in Leesburg and Ashburn, VA. We owe all of our success to you, our Ashburn and Leesburg customers who support us and we want to thank you! The highest compliment we receive is the trust in your referral and we truly appreciate your support!
We maintain a complaint-free A+ rating with the Better Business Bureau, and are a 2017 Better Business Award Winner for ethics. Comfort Plus Services has achieved recognition as a Carrier Factory Authorized Dealer for sound business practices, technical expertise, and customer approval ratings. We simplify the demands of local weather and a comfortable home with upfront pricing, honest estimates, comprehensive service plans, and Emergency Service throughout Salisbury, Fruitland, Delmar, Hebron, Eden, Delmar, Parsonsburg, Pittsville, Mardela Springs, Princess Anne & Willards, MD and more. See our Areas of Service. For new home comfort systems, Comfort Plus Services protects your interests with a 100% money back guarantee. We provide expert service you can trust.
Relax—ABC Plumbing, Heating, Cooling & Electric is here for you when you need us most! Our highly trained, background-checked technicians perform heating and air conditioning repairs quickly and efficiently to keep your family warm and cozy all winter long. With over 65 years of experience, you can trust that we’ll fix your furnace correctly the first time.
"Tyler was very professional and gave us all the information we needed to make good decisions without any pressure. I appreciated how quick he was able to do the service, give a detailed assessment of our system, and provide options. I look forward to working with him again. If he is an example of the employees of the Green Valley Cooling & Heating, then this is a thorough and honest business to work with. Thank you."
Packaged terminal heat pumps (PTHP) are are similar to a window-mounted air conditioner. These units are typically installed in a sleeve passing through the outdoor wall of an apartment, hotel, school classroom, etc. PTHPs are completely self contained and require only an electrical connection in addition to the opening in the building shell. They use the outdoor air as the heat source in winter and as a heat sink in summer. They also can provide ventilation air. Flexibility and lower installed cost are the primary advantages of the PTHP. Disadvantages include in-room maintenance, higher operating cost, relatively short life, imprecise "on-off" temperature control, and they can be rather noisy.
I need a complete system replacement , before I was trying to get an evaporator coil replaced , of course the price is between $2200 an $2800 , then get told it probably will over tax my ac unit within months , so now and like everyone else what do you buy 14 ,15 16 17 seer units ,price and how do we know its reasonable  why can't there be '" a estimated price ,in the ball park, a range of prices ,so we can at least go from their .....  Now it's from 7500 to 15000. Frustrating  from the start so everybody good LUCK.   Draw a # from the hat    Unregulated  and who do you BELIEVE, just like on NCIS go with your gut feelin   
Since 1968, Eanes Heating and Air Conditioning has been providing high-quality heating and cooling products and services across the Piedmont Triad Area of North Carolina. Centrally located in High Point, NC, the Eanes service area covers the cities of Greensboro, Winston Salem, Kernersville, Thomasville, Lexington, Randleman, and all points in between. As a local, family-owned business, Eanes takes great pride in providing trusted advice and straight talk service on HVAC installation, repair, and maintenance for both commercial and residential applications. With a commitment to service and integrity, the company is driven by a set of values that have contributed to its continued growth and success.

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.


BGE HOME HVAC repair technicians are thoroughly trained and certified to work on all major brands of heating and air conditioning equipment. When your system breaks down and needs a heating and air conditioning repair, you want to call someone you can trust. Need air conditioning service in the middle of the night? Emergency heating and cooling HVAC service is available 24 hours a day by calling 888-243-4663.
The Rack Cooling Index (RCI) is a metric that measures the percentage of racks in the data centre where the air inlet temperature is at the recommended or allowable level under the guidelines put forth by ASHRAE. RCI (hi) is the metric for racks at the upper limit and RCI (lo) for racks at the lower limit. This metric reveals how uniformly and efficiently a data centre is being cooled.
Mr. Plumber provides fast, expert plumbing service to Smyrna, GA and is here for you with 24 hour emergency plumbing service. Our licensed and certified plumbers can tackle all your plumbing jobs including sink & faucet repair, toilet repair & replacement, water line repair & replacement, drain cleaning, bathtubs & shower installation and repair, water heater installation, sewer repair, backflow prevention and more. Our professional plumbers will respect your time, home and business. You approve the price before we perform our plumbing work and your satisfaction is guaranteed! Give us a call today for:
The most recognized standards for HVAC design are based on ASHRAE data. The most general of four volumes of the ASHRAE Handbook is Fundamentals; it includes heating and cooling calculations. Each volume of the ASHRAE Handbook is updated every four years. The design professional must consult ASHRAE data for the standards of design and care as the typical building codes provide little to no information on HVAC design practices; codes such as the UMC and IMC do include much detail on installation requirements, however. Other useful reference materials include items from SMACNA, ACGIH, and technical trade journals.
As a Carrier and GeoComfort dealer, with a wide variety of products to choose from, we can keep your family healthy and feeling comfortable all year long. We carry a complete line of energy efficient equipment with innovations that raise the standards of comfort and reliability, including air conditioners, heat pumps, gas furnaces, geothermal systems, programmable thermostats, humidifiers, air cleaners, ventilators and zoning products. Let the experts at Derousseau Heating & Cooling, Inc. help customize a solution that's right for you.
If you are installing an AC system from scratch, your contractor should calculate the size of the cooling equipment you need by using recognized methods such as what you’ll find in the Residential Load Calculation Manual, aka Manual J, from the Air Conditioning Contractors of America (ACCA). If you already have ductwork for your heating, adding a central system can cost less.
A dehumidifier is an air-conditioner-like device that controls the humidity of a room or building. It is often employed in basements which have a higher relative humidity because of their lower temperature (and propensity for damp floors and walls). In food retailing establishments, large open chiller cabinets are highly effective at dehumidifying the internal air. Conversely, a humidifier increases the humidity of a building.
Vredevoogd Heating & Cooling stands behind its services and products with the strongest guarantees you’ll find anywhere. When you invite us into your home to service or install your HVAC system or do Furnace Repair work in Grand Rapids and beyond, we perform our job with an outstanding level of care and efficiency. Having served Michigan for 54 years, we never rest on our laurels. To remain the best, we intend to give our best every time, every job.
When your furnace isn’t regularly serviced it can operate less efficiently. This increases your energy bills and also prevents your furnace from keeping your home as warm as you like. Keep your furnace properly maintained with regular service. The national average furnace service cost is between $60 and $80. Companies may offer tuneup specials that cover all the necessary testing, tightening, measuring and cleaning to keep your equipment running at top efficiency. If you have a newer system, furnace service costs may be covered by your warranty. Outside of warranty, a basic tuneup might start at $58 and a more advanced maintenance cleaning could be over $120. Here are some signs your furnace may need service:
You should also have air ducts cleaned after recent water contamination or water damage to prevent mold; after renovations or remodeling to ensure debris and dust didn’t settle in the vents and ducts; if you are having problems with allergies or asthma; or when you are moving into a newly purchased home, especially if the previous owners smoked or had pets. The National Air Duct Cleaners Association (NADCA) recommends getting your air ducts cleaned every three to five years, or every two to three years in regions where homeowners use their air conditioning and heater for many months of the year, while the EPA suggests homeowners have duct cleaning done as needed.
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).

Before selecting the installation location of air conditioner, several main factors need to be considered. First of all, the direction of air flow from the indoor units should not fall on the place of rest or work area. Secondly, there should not be any obstacles on the way of the airflow that might prevent it from covering the space of the premises as much as possible. The outdoor unit must also be located in an open space, otherwise the heat from the house will not be effectively discharged outside and the productivity of the entire system will drop sharply. It is highly advisable to install the air conditioner units in easily accessible places, for further maintenance during operation.
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.

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.


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]
As a Bryant Factory Authorized Dealer, Cool Care Heating & Air installs durable, high-quality heating systems that will go the distance. Are you considering a heater installation or heating repair? If so, you have found the best HVAC dealer in the Columbia, SC area. We specialize in high-efficiency furnaces, heat pumps and boilers that can cut energy costs month after month.
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