If you are using existing ducting, it will have to be inspected. Proper ducting loses around 2% to 5% of your energy. Old, leaking ducts can lose 50% or more. A contractor will need to have the ducts inspected and replace any parts ahead of time. If you are changing the size of your HVAC system because of significant changes to your home, you might need to replace the ductwork regardless.
We installed a TRANE XL18 HVAC with a TRANE HV80 furnace 16 years ago and it still works great in Tucson, AZ.  We inquired into a replacement for the future since the R-22 refrigerant will be off market at the end of this year.  Our maintenance folks want to sell me a new system anyway (even though the TRANE works great).  We are considering the BOSCH Inverter heat pump as a lower cost option down the road.  Watch out for the tricky salesmen trying to sell beer at champagne prices though. Get estimates on whether you need to replace your current system and how much it could cost.  And if they are factory certified.

It seems all the average costs for a complete heating and cooling system replacement I've found on websites are usually at least 1/4 less, mostly half lower, then quotes I've gotten from companies. The worst quote I got was from One Hour Heating & Air Conditioning (the company with the Mike Rowe commercials), for over $15,000! I finally settled on a Carrier dealer, for $10,700 & I'll get $950 of that back in energy co rebates eventually. The company I went with's basic system would have been around $8800 (the only one that sorta matched up with web avg cost). They did all the correct planning as far as I could see, not like One Hour, who just showed me a price guide for the same size units already in place. And they do all the rebate paperwork and submit it to the energy co, One Hour never even mentioned possible rebates! Plus Carrier gets above avg reviews. I would have greatly liked a price under 9 grand, but this company got me 0% APR financing, so at least nothing out of pocket. My advice is stay away from national chains, and shop around with local area companies. Of course, One Hour says local companies will fold before you need warranty service lol. For their cost, there should be a technician living in his work van outside my house hahaha.


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.

If you are using existing ducting, it will have to be inspected. Proper ducting loses around 2% to 5% of your energy. Old, leaking ducts can lose 50% or more. A contractor will need to have the ducts inspected and replace any parts ahead of time. If you are changing the size of your HVAC system because of significant changes to your home, you might need to replace the ductwork regardless.


Capacitors -- Capacitors help your HVAC motor start from a standstill. Over time they can weaken. As they weaken, they cause the motor to run hotter. This can shorten the life expectancy of your motor. Once a capacitor fails, the whole motor will stop working. You usually won't notice that a capacitor has weakened until your motor stops turning on.
Feel perfectly comfortable at home with our innovative Lennox Residential heating, cooling and air quality systems. Lennox manufactures high-efficiency HVAC systems including furnaces and air conditioners designed to conserve energy and save money. Our complementing air filtration systems, humidifiers and dehumidifiers help keep indoor air quality healthy and clean.
Pro Tips: Before you buy one of the learning thermostats available, you should beware of their shortcomings. First, many require a c-wire to work properly. A common problem is that the old thermostat might not use a c-wire, and this makes it confusing when swapping wires to the new thermostat. Secondly, if you change your thermostat setting often, you might become frustrated with a nest thermostat or other learning thermostat. It will be constantly trying to learn patterns in your random setting changes, and will therefore change your home’s temperature when you don’t want it to. If you have a fairly consistent schedule or don’t mind overriding the unit either manually or via the app on your way home or when leaving, then you won’t experience this issue.
As for the price I think my review was fair in stating what value we got for what I deemed to be a slightly higher price than others might charge.  I did not take any stars off for the price, and still am not, but I am taking another star off because of Alberto's comments, which are deceptive and not the same thing he told me in person.  Alberto, I suggest you stick with the high road in the future.
Installing a split system may involve making modifications to the house itself for the necessary lines to be run. The heat exchangers are also more prone to picking up debris and must be cleaned on a regular basis. While they come with protective screens over the fan, care must still be taken to ensure that nothing gets in, especially in a home with children.

Your contractor will do a load calculation to determine the proper central air conditioning unit for your home. This calculation accounts for the climate, size, shape and orientation of your home, as well as its square footage. A professional will also look at the insulation, windows, walls, floors and other materials that compose your home. He/she will then examine any leaks, seals and existing ducts or vents.

While a lot of people understand the consequences of AC problems throughout the summer, the summer comes with its own set of unique issues that require a call to the plumber, too. Whether it’s a malfunctioning sprinkler system or a sewer line backup, Service Experts can help. We’ve encountered it all, and you won’t have to worry about any of it with our 24/7/365 Emergency Plumbing Service. When you need a plumber, we are here for you. And, just like all of our other services and products, any plumbing repair or work completed by Service Experts is backed by the same 100% Satisfaction Guarantee*.
Feel perfectly comfortable at home with our innovative Lennox Residential heating, cooling and air quality systems. Lennox manufactures high-efficiency HVAC systems including furnaces and air conditioners designed to conserve energy and save money. Our complementing air filtration systems, humidifiers and dehumidifiers help keep indoor air quality healthy and clean.
The performance of vapor compression refrigeration cycles[26] 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.[27][dead link]
Multiple inventions within this time frame preceded the beginnings of first comfort air conditioning system, which was designed in 1902 by Alfred Wolff (Cooper, 2003) for the New York Stock Exchange, while Willis Carrier equipped the Sacketts-Wilhems Printing Company with the process AC unit the same year. Coyne College was the first school to offer HVAC training in 1899.[12]
The use of furnaces, space heaters, and boilers as a method of indoor heating could result in incomplete combustion and the emission of carbon monoxide, nitrogen oxides, formaldehyde, volatile organic compounds, and other combustion byproducts. Incomplete combustion occurs when there is insufficient oxygen; the inputs are fuels containing various contaminants and the outputs are harmful byproducts, most dangerously carbon monoxide, which is a tasteless and odorless gas with serious adverse health effects.[14]
Humidifiers/Dehumidifiers: Humidifiers add needed moisture to the air in winter and very dry climates. Dehumidifiers remove dampness any time of the year. Central air conditioners dehumidify too, but in very humid climates, you might want to remove humidity without also cooling the air. You have a good range of options for both of these HVAC accessories. Whole-house humidifiers cost $350 to $800 installed, while dehumidifiers are $1,250 to $2,000 or slightly more.

Dehumidification (air drying) in an air conditioning system is provided by the evaporator. Since the evaporator operates at a temperature below the dew point, moisture in the air condenses on the evaporator coil tubes. This moisture is collected at the bottom of the evaporator in a pan and removed by piping to a central drain or onto the ground outside.
You can install the greatest HVAC system ever built, but if your house is not insulated well, it's only going to end up costing you more money. Older homes may have fiberglass insulation that has broken down due to pests, moisture, or improper installation. Spray foam insulation can be damaged by careless repair or modification work or can be improperly installed. If your insulation in compromised, your attempts to save money and be comfortable will be in vain.

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]
The three major functions of heating, ventilation, and air conditioning are interrelated, especially with the need to provide thermal comfort and acceptable indoor air quality within reasonable installation, operation, and maintenance costs. HVAC systems can be used in both domestic and commercial environments. HVAC systems can provide ventilation, and maintain pressure relationships between spaces. The means of air delivery and removal from spaces is known as room air distribution.[3]
There are multiple reasons to replace your HVAC system. If you have built additions onto your house, you may find your old system no longer meets the requirements for the new dimensions. Perhaps a new technological breakthrough has provided features that will improve your comfort and air quality. Most often, however, you need to replace your system because it no longer works properly.
Duct system installation and repairs affect HVAC installation cost. If you’re installing a new forced air heating or cooling system, your home must have ductwork – if you don’t have ducts installed, a new duct system will need to be designed and installed. Your existing duct system may require air sealing to eliminate air loss, helping your new heating and cooling system operate efficiently.
An alternative to packaged systems is the use of separate indoor and outdoor coils in split systems. Split systems are preferred and widely used worldwide except in North America. In North America, split systems are most often seen in residential applications, but they are gaining popularity in small commercial buildings. The split systems are a great choice for small buildings where ductwork is not feasible or where the space conditioning efficiency is of prime concern [20]. The benefits of ductless air conditioning systems include easy installation, no ductwork, greater zonal control, flexibility of control and quiet operation [21]. In space conditioning, the duct losses can account for 30% of energy consumption [22]. The use of minisplit can result in energy savings in space conditioning as there are no losses associated with ducting.
Installing a split system may involve making modifications to the house itself for the necessary lines to be run. The heat exchangers are also more prone to picking up debris and must be cleaned on a regular basis. While they come with protective screens over the fan, care must still be taken to ensure that nothing gets in, especially in a home with children.
Having the most energy-efficient system ever built won't matter much if it's not maintained. Lack of maintenance is the number one killer of HVAC systems. Before each cooling season, it's recommended that your system get a professional tune-up. However, there are things you can do in the meantime to make sure your system runs efficiently throughout the year.

DIY: Most DIY installations go smoothly. The major brands have compatibility checkers to see which of their models will work with the wiring your old thermostat is using. Potential problems involve the need for a C-wire, or common wire, when the existing bundle doesn’t include one. There are solutions discussed in our Thermostat Buying Guide, linked to below.
Dehumidification (air drying) in an air conditioning system is provided by the evaporator. Since the evaporator operates at a temperature below the dew point, moisture in the air condenses on the evaporator coil tubes. This moisture is collected at the bottom of the evaporator in a pan and removed by piping to a central drain or onto the ground outside.
Knowing what you should be paying for your HVAC equipment and installation is essential to getting a fair deal. Most HVAC prices aren’t advertised. Contractor strategy is to get a salesperson into your home to sell you on a package of equipment, accessories and installation. This makes comparing systems difficult, and some sales pressure might be applied.
If the condenser coils are clogged, the compressor can overheat and shut down. You'll experience intermittent periods of minimal cooling, followed by no cooling. Even if you're “sure” the condenser coils are clean, clean them again. Turn off the power. Flip the air conditioning service and furnace circuit breakers in your main electrical panel to the “Off” position. Next, turn off the power switch right at the furnace or air handler. Then yank the disconnect block (Photo 1) and clean the condenser coils (Photo 2). If the air conditioning service still doesn't work properly after you've cleaned the condenser coils, installed a new filter and opened all the supply vents, proceed with the following repairs. Your AC won't work fully unless you do this.
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