Heating & Cooling Cost Guides

Let the neighbors know:
Your HVAC system is arguably one of the most important aspects of home maintenance and one you will notice the most when it's not working. Make sure you understand all the details involved in this project before you proceed, and keep in mind the following considerations.
  • Repair an A/C Unit Costs
    Most homeowners spent between:
    $167 - $498
    Average cost:
    $319
    Low cost:
    $79
     
    High cost:
    $900
  • Repair a Furnace Costs
    Most homeowners spent between:
    $136 - $423
    Average cost:
    $270
    Low cost:
    $59
     
    High cost:
    $800
  • Install an AC Unit Costs
    Most homeowners spent between:
    $3,680 - $7,169
    Average cost:
    $5,208
    Low cost:
    $1,800
     
    High cost:
    $10,000

Select your Heating & Cooling project

Heating & Cooling
Repair an A/C Unit
(21,920 projects)
Average National Cost:
$319
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Heating & Cooling
Repair a Furnace
(11,632 projects)
Average National Cost:
$270
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Heating & Cooling
Install an AC Unit
(8,657 projects)
Average National Cost:
$5,208
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Heating & Cooling
Clean Chimney or Fireplace
(8,580 projects)
Average National Cost:
$206
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Heating & Cooling
Clean Ducts & Vents
(7,632 projects)
Average National Cost:
$331
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Heating & Cooling
Install a Furnace
(5,573 projects)
Average National Cost:
$3,869
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Heating & Cooling
Install a Ceiling Fan
(4,646 projects)
Average National Cost:
$244
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Heating & Cooling
Install Batt, Rolled, or Reflective Insulation
(3,454 projects)
Average National Cost:
$1,526
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Heating & Cooling
Install or Repair Gas Pipes
(3,008 projects)
Average National Cost:
$487
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Heating & Cooling
Repair a Fireplace or Woodstove
(2,743 projects)
Average National Cost:
$435
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Heating & Cooling
Install a Heat Pump
(2,353 projects)
Average National Cost:
$5,251
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Heating & Cooling
Repair a Boiler
(2,025 projects)
Average National Cost:
$354
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Heating & Cooling
Install an Attic Fan
(1,915 projects)
Average National Cost:
$546
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Heating & Cooling
Repair a Heat Pump
(1,791 projects)
Average National Cost:
$341
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Heating & Cooling
Install Ducts & Vents
(1,546 projects)
Average National Cost:
$1,032
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Heating & Cooling
Install a Boiler
(1,074 projects)
Average National Cost:
$4,963
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Heating & Cooling
Repair an Attic Fan
(992 projects)
Average National Cost:
$275
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Heating & Cooling
Repair a Ceiling Fan
(834 projects)
Average National Cost:
$130
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Heating & Cooling
Install a Fireplace or Woodstove
(567 projects)
Average National Cost:
$1,842
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Heating & Cooling
Install a Thermostat
(547 projects)
Average National Cost:
$166
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Heating & Cooling
Repair a Swamp Cooler
(529 projects)
Average National Cost:
$183
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Heating & Cooling
Install a Humidifier
(433 projects)
Average National Cost:
$499
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Heating & Cooling
Install a Window Air Conditioner
(330 projects)
Average National Cost:
$298
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Heating & Cooling
Install Weather-stripping
(274 projects)
Average National Cost:
$238
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Heating & Cooling
Install a Swamp Cooler
(273 projects)
Average National Cost:
$2,418
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Heating & Cooling
Repair a Thermostat
(273 projects)
Average National Cost:
$190
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Heating & Cooling
Repair A Window Air Conditioner
(195 projects)
Average National Cost:
$214
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Heating & Cooling
Repair an Electric Baseboard or Wall Heater
(174 projects)
Average National Cost:
$248
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Heating & Cooling
Install an Electric Baseboard or Wall Heater
(163 projects)
Average National Cost:
$630
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Heating & Cooling
Install Solar Panels
(156 projects)
Average National Cost:
$17,086
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Heating & Cooling
Repair a Humidifier
(117 projects)
Average National Cost:
$205
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Heating & Cooling
Repair a Radiant Heating System
(110 projects)
Average National Cost:
$413
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Heating & Cooling
Repair a Whole House Air Cleaner
(96 projects)
Average National Cost:
$245
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Heating & Cooling
Repair a Refrigeration System
(87 projects)
Average National Cost:
$254
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Heating & Cooling
Install a Geothermal Heating or Cooling System
(79 projects)
Average National Cost:
$5,389
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Heating & Cooling
Repair a Geothermal Heating or Cooling System
(57 projects)
Average National Cost:
$423
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Heating & Cooling
Install a Whole House Air Cleaner
(52 projects)
Average National Cost:
$1,125
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Heating & Cooling
Install a Radiant Heating System
(51 projects)
Average National Cost:
$3,168
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Heating & Cooling
Repair Solar Panels
(51 projects)
Average National Cost:
$466
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Heating & Cooling
Fabricate Sheet Metal
(14 projects)
Average National Cost:
$1,157
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Heating & Cooling
Install a Refrigeration System
(9 projects)
Average National Cost:
$697
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Amana -- $3,900 - $4,800

Amana's Premium AGP15 Gas/Electric Package is a very popular model for all climates. It uses gas for heating and electricity for cooling. It also features a louvered compartment for the compressor to help protect it from the elements and from dust and debris. 15 SEER, 80% AFUE, available in 2 to 5 tons.

American Standard – $3,800 - $4,900

American Standard's Gold line continues to be their best selling HVAC line. Sturdy steel construction with a variable speed fan helps protect the system while saving about 40% on your energy bill. A corrosion resistant blower ensures a long life for your system. 14.25 SEER, 80% AFUE, available in 2 to 5 tons.

Bryant -- $3,900 - $4,900

Bryant offers a high quality, economical model with their Evolution line. Bryant focuses on quiet comfort, delivering 40,000-100,000 BTU heating with 2-5 tons cooling. 15 SEER and 80% AFUE.

Carrier -- $3,400 - $4,600

Carrier's Comfort Series includes options such as blower-enhanced dehumidification. The Comfort Series 48ES has a 13 SEER and 81% AFUE. Available in 2-5 tons.

Lennox -- $3,600 - $4,500

The Lennox Elite Series 13GCSX maintains its efficiency in almost any climate. Able to handle enhanced filtration with an internally mounted filter rack, this model is available in 2-5 tons. 13 SEER, 80% AFUE.

Rheem -- $2,300 - $3,400

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.

Trane -- $3,500 - $4,600

Trane's XL13c is built for aesthetics as well as performance. A cabinet designed to fit with almost any architectural style contains a stainless steel heat exchanger and a system designed to perform well year after year. Available from 1.5-5 tons. 13 SEER, 80% AFUE.

Other Heating & Cooling System Factors

Consider what kind of heating and cooling system you want installed for the square footage of your home. Do you want a full system with a thermostat or a specific machine for the summer like a swamp cooler? Do you need a new furnace just for the winter? For any of these projects, the cost will vary depending on the quality, style and machine size you choose. If you have a tight budget, think of going smaller and upgrading over time. For example, if you can't afford to convert your entire home to solar power, you may want to consider only utilizing it to heat your water. Some other types of heating systems are:
  • Geothermal heating & cooling ($4,500 - $6,000): Considered an eco-friendly heating and cooling option, these systems use energy in the earth to pump heat into a home. It uses equipment that goes into the earth's crust and pulls heat out into a home.
  • Attic fans ($350 - $800): Used mostly to cut down the amount of heat in your attic, these are good for homes that don't get cold, frosty winters and want to cut down their air conditioning use in the summer. Attic fans are great for getting the humidity out and cutting down moisture above your ceiling.
  • Electronic baseboard heaters ($300 - $950): These are an affordable alternative to a whole-house heater if you don't want to install ducts and vents. They're good for small apartments or condos if you need to keep one or two rooms warm.
  • Radiant heating ($1,600 - $5,000): Although not considered a traditional home heating method, radiant heating is great for home environments without real winters but chilly nights where you don't want to walk across cold floors in your kitchen or bathroom.
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.

Insulation

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.

How much insulation you need depends on where you live. Obviously, you will need better insulation in colder or warmer climates than you will in temperate regions. But how much is too much, and how much is too little?

Insulation is available in many different forms and is suitable for particular areas. According to the Department of Energy, these are:
  • Blanket: Batt and Roll -- The most common type of insulation, it is usually made of fiberglass, though some can be made of wool, natural fibers, plastic, or minerals (rock and slag).
  • Concrete Blocks -- Concrete blocks are used in foundations and are often found in full basements. Insulating the spaces in the blocks is not the way to insulate them as the heat energy will travel along the concrete itself. The best way to insulate with concrete blocks is to use insulated concrete blocks, which have polystyrene incorporated into them.
  • Foam Board -- This is most commonly used for unfinished interior walls. To meet fire safety codes, it must be covered with gypsum board.
  • Insulating Concrete Forms -- Made in board and block forms, these foam elements are incorporated right into the construction of a building.
  • Loose Fill -- This somewhat fluffy-looking insulation is often used to add insulation to an area. It gets sprayed or poured in.
  • Reflective System -- Foil-faced insulation used where downward heat flow is an issue. While you can combine insulation types, foil-faced insulation often requires the foil facing to be removed first.
  • Rigid Fibrous Insulation -- This is fiberglass insulation that has been set into a specific shape, such as being made to fit ducting. It can withstand high heat.
  • Sprayed Foam Insulation -- This insulation is best used by injecting into finished walls or for insulating irregularly spaced areas or going around obstructions.
  • Structural Insulated Panels -- These are sections of wall built with the insulation already inside. Houses built of these panels are so far the most energy-efficient houses around.
Depending on the insulation, you can see a R-value of R1 to R3 per square inch, though Insulated Concrete Forms can have an R-value of R20.

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HVAC Labor Cost Factors

If you need a new heating and cooling system installed, the highest cost will likely be for labor. Some factors involved with labor pricing will be:
  • Size, placement and parts, like vents and ducts
  • Installation
Get free quotes from local heating and air conditioning contractors if you have a specific job in mind.

NOTE: Improperly designed systems may have ducts too small for the amount of air blowing out, or an overly large duct may siphon off air that should be going to another part of the house. The HVAC system could be undersized or too large as well, providing more or less pressure than ducts are designed to handle.

A contractor can do a mathematical calculation to determine what size HVAC system your home needs based on:
  • Type of materials you are using
  • Indoor air quality desired
  • Size of your home
The placement of your vents and ducts is crucial for keeping your house at a comfortable temperature year-round. If vents are placed where you plan to put down furniture or in the largest room of your home, there are going to be issues and could increase total costs.

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Installing an HVAC System

Installing an HVAC system involves determining whether the unit is going to be roof-mounted or a split system.

Roof-Mounted HVAC

Roof-mounted systems have the heating and cooling systems in one cabinet. Sometimes called "gas packs" (if the heater uses natural gas), they typically cost less than a comparable split system. In dry regions, most homes originally had "swamp-coolers" installed. When replacing them with HVAC systems, it's often cheaper to use existing mounts and ducting.

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.

Split HVAC System

Split systems are generally more efficient because the heat exchanger can be put in a shadier or cooler location instead of on the roof in full sunlight. All that is needed for the heat exchanger is a concrete platform in the right spot.

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.

Unit Size

Bigger is not necessarily better when it comes to HVAC systems, and smaller isn't always more efficient. If you have too small of a system, your system will be running constantly as it tries to keep up with the temperature. If you have too large of a system, it won't run long enough to keep up with the humidity. In order to handle both temperature and humidity efficiently, an HVAC system should run for around 30 minutes at a time. If your system is staying on too long or shutting off after only around 10 minutes, you are not getting efficient performance.

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.

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Further Considerations

Further considerations include the following:
  • Single stage or multi-stage? -- Single stage systems have one speed designed to provide maximum comfort. They run at full power even when they don't have to. A multi-stage system adjusts itself as needed to maintain comfort. While more expensive upfront, these systems offer greater savings in the long run.
  • Zoned systems -- Zoned systems monitor areas of your house and only heat or cool the ones that need it. Dampers in the ducting close off areas of the house to divert the airflow only to certain rooms.
  • Humidity control -- This is a must-have in very dry or humid climates. Remember humidifiers or dehumidifiers do not work when the system is not on, so you may want to see about a separate humidifying system.
  • 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.

Ductwork

Ductwork in your house is one of the main sources of loss of efficiency with your HVAC unit. If you are installing a completely new system, the contractor will have to map out:
  • Ducts: to ensure that the air is being efficiently circulated throughout your home.
  • Vents: so they send the air out correctly, and it must be determined if these vents will be in the ceiling or the floor
  • Floor vents: so that they are not going to be blocked by furniture or other objects.
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.

Thermostat

Wiring up the thermostat is usually pretty straightforward if an old one is being replaced. If a thermostat is being put in where one had never been before, that could involve running new wiring. The placement of the thermostat is also important so that its sensors can get an accurate reading of the temperature. A thermostat that is blocked by a bookcase or other large furniture will not get a good reading and will not perform efficiently.

Thermostats are available in many types:
  • Dial-type or small boxes with levers: These are usually manually adjusted as environmental temperatures change and seen as very inefficient. However, there is no battery to replace every few months.
    • The lever also makes adjustments as the system responds immediately. Many digital, programmable thermostats have a "tolerance" of 2 to 4 degrees, so the response may not be immediate.
    • There are also digital manual units, where you get digital readouts and buttons but still get to control it manually like you would a lever.
Programmable thermostats are more efficient than manual thermostats.
  • It saves time: You can schedule temperatures according to the time of day and day of the week.
  • You can adjust for seasons: During the summer, you can have the air conditioner stay off during the cooler morning hours and start cooling the house as everyone gets up and starts moving around. During the winter, you can have your heater stay off while you are away at work and turn on about a half hour or so before you get home so that you are coming home to a nice, warm house.
  • It's always changing: Some newer thermostats take advantage of wireless technology. You can adjust your thermostat remotely so that if you leave and forget to adjust it, or if you are going to be home later than you thought, you can adjust it via your smartphone. Some can even give you reports on how efficient your system is performing based on usage. These are very efficient models, but they are also very expensive with some costing over $250.00.
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How Does An HVAC System Work?

Cooling

An air conditioner's compressor contains a refrigerant. As it works, it sends this refrigerant through the system. As warm air blows across the coil that carries this refrigerant, the heat transfers to the refrigerant (cool always absorbs warm). A fan moves the cooled air through the ducting and out of vents that lead into the rooms of your house. The refrigerant returns to the compressor where the absorbed heat is moved outside. The refrigerant is then sent through the coil once again to continue the cycle.

Heating

In a split system, the heater or furnace will be located away from the air conditioner. It may be in a garage or a basement. In a package unit, sometimes called a "gas pack", the heater is in the same cabinet as the air conditioner. All heating systems will have four elements in common:
  • Burners that burn fuel and deliver it
  • Heat exchangers
  • A blower that pushes the air along
  • An exhaust flue
In a manner similar to the coil described above in the cooling section, the burners heat up the fuel and send it through the heat exchanger. Cool air blows across the heat exchanger and absorbs the heat. The blower then sends it through the ducts and into the rooms of your house. The flue sends any exhaust gases safely out of your house.

All of this is controlled by the thermostat as it communicates with your HVAC system's circuitry. It tells the system when to heat, when to cool, when to stop and when to run. Some systems control the temperature according to the whole house while others can control it room by room.

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Components of an HVAC System

What is involved in installing an HVAC system? Know it's a genuine "system" with several independent components and functions that work together to produce an effect.
At its most basic, an HVAC system consists of:
  • An air conditioner that cools the air in your home. This works with an evaporator to make up the system that helps cool your home in the warm months. It's most often powered by electricity.
  • A furnace that warms and circulates the air in your home. Furnaces are powered by many different sources such as electricity, solar, or geothermal, but most often they are powered by natural gas.
  • Ducting that serves as a highway for the conditioned air to travel to your rooms. Ducting is normally made of stamped sheet metal, but expansion and contraction can cause leaks to form. Some contractors will install flexible ducting that won't wear out so easily.
  • A thermostat that controls when the system turns on and off. Thermostats can be manual, programmable, and some work wirelessly so you can control them remotely from your smartphone.
There are other components of an HVAC system that may or may not be present in a standard installation. These features are:
  • A germicidal UV light: This feature sterilizes the air, purifying to a level often found in hospitals. While it's comfortable to breathe clean air, for those with conditions or compromised immune systems, it can be a very important part of their HVAC system.
  • A central humidifier: This helps maintain the level of humidity in the air in your home. Scientists have determined that most people are comfortable at 50% humidity. This keeps the air from being too dry or too humid and cuts down on static electricity. It can also help people with respiratory conditions such as COPD or chronic asthma.
  • 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.
  • An electronic air cleaner: This additional filtration helps keep pollen and other allergens from getting into your system and circulating throughout the house. See how much it costs to install a whole house air purifier or cleaner.
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Repairing or Replacing Your Existing HVAC System

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.

Repairing your system is sometimes more cost-effective than replacing it. The two areas that see the most common repairs are the electrical components and the piping components.

Electrical Repair Components

  • 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.
  • Compressor -- Compressors are outdoor components in your system. The compressor is the pump that circulates the refrigerants through the air-conditioner. You can hear it when it's running so you'll know if it's working just by listening. If it starts getting louder, your compressor is about to fail. If it makes no sound when it should be on, it has already failed. Compressors fail for a number of reasons. Most often they fail due to strain from another failed part such as the fan motor. Electrical storms can also damage compressors. If the sound from the compressor gets louder or if you see a decrease in performance, you should have your compressor checked. A failed compressor will not heat or cool your house.
  • Contact/Relay -- Relays are electronically controlled switches that activate the various components of your HVAC system. They manage everything from the power going to the motor to automatic dampers, humidifiers, etc. Most of them are controlled by the thermostat. The most common failure for a relay is being stuck in the "open" position. Separated from its assigned contact point, it fails to complete the connection and send the message to whatever it was supposed to operate. This failure usually occurs from use over time. Each time a relay connects and sends its signal, the electrical arcing from point to point eventually causes wear and tear.
  • Furnace Circuit Board -- The furnace circuit board controls a variety of functions. It not only handles the regular operation of the furnace, it also monitors the furnace's various safety circuits. Over time, vibrations from the furnace can weaken solder point and cause them to separate. Dirt and debris can cause short-circuits that damage the board. Failure of the circuit board can cause a variety of effects ranging from the fan not turning on to the complete shutdown of the furnace.
  • Fuses -- Anyone who has worked with electrical systems knows all about fuses and how they fail. They can burn out over time, may just be loose, or can blow out during an electrical storm or due to overload from another failed component. Of course, that's what they're supposed to do; they stop surges from going through and damaging the rest of the system. When a fuse fails, whatever system it was protecting will stop working.
  • Gas Valves -- On a gas furnace, a gas valve can become stuck due to dirt or debris building up after sitting idle all summer. A gas valve that is stuck closed will provide no heat.
  • Indoor Fan Motor -- Indoor fans circulate the air from your house and through the system. Age and dust buildup are the two biggest contributing factors to their failure. When they are starting to fail they will often make noise. Failure of the fan will result in no heating or cooling, and if it is not repaired soon, it can cause other components to fail.
  • Outdoor Fan Motor -- The outdoor fan, also called the condenser fan, is exposed to external conditions. As such it is most prone to dust and debris and the extreme weather. In desert climates, the outdoor fan motor is subject to heat not only from normal operation but from the outside temperature as well. As it starts to fail, the fan may work fine in the cooler morning hours but stop by afternoon. This can shut down the entire system for hours. When they stop running completely, your air conditioner will no longer work. Running a faulty fan will lead to compressor failure, which is a very costly repair.
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Pipe Repair Areas

  • Drain Lines -- Dirt, debris, and hard water can build up in your drain lines and cause the drain pan to overflow. Drain lines rarely give any kind of warning that they are blocked. They should be cleaned annually to prevent water damage from overflow.
  • Indoor Coil -- The indoor coil is a heat transfer device. It absorbs the heat from the inside of the house and passes it on to the refrigerant and is pumped outside. Dust that builds up on the coil can hamper its ability to absorb heat. High heat transference coils use very thin metal. Airborne chemicals can cause corrosion which leads to leaks. The constant vibration of the compressor can also cause solder joints to weaken and leak. An indoor coil may operate for weeks with a tiny leak, and you may not notice the loss in performance right away. As soon as a leak is made known, it should be replaced or repaired immediately.
  • Outdoor Coil -- The outdoor coil is similar to the indoor coil except that it deals with the outside air, using it to absorb heat from the coil. It can suffer the same problems as an indoor coil. The difference is that since the refrigerant is under high pressure, even a small leak can lead to a complete loss of air-cooling ability.
  • Refrigerant Metering Device -- Every HVAC system has one of these, and heat pumps have two. They regulate the amount of refrigerant going through your air-conditioner. If it fails, either too much or too little refrigerant will course along the lines and either not perform well or will overwhelm the compressor and cause it to fail. A total failure of this component will result in a complete loss of operation.
  • Restriction -- Any kind of blockage anywhere in your system will lead to reduced performance or failure altogether. Filters can get clogged and need replacing, or a filter may have failed to block debris from getting through. Some filters are replaceable quite easily while others may need a little more work.
  • Reversing Valve -- The reversing valve is what allows your system to go from cooling to heating and back again. If this valve gets stuck in one position it will not be able to switch to the other mode. If it fails midway between the two, your system will not function at all. Debris is usually culprit for these valves sticking.
Some of these components can be repaired or replaced by the homeowner, such as filters, fuses, and clogged up drain lines. Coils, compressors and the other components are best left to a professional. In some cases, you may have a system that is so old that parts are no longer available or else they aren't up to code. In this case you will have to consider replacing the entire system.

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Entire System Replacement

When replacing your HVAC system, you need to know what size to get. If you haven't made any additions to your home, you should be able to stay with the same size system. If you have made additions, even if it was just turning your garage or attic into a livable space, you will have to recalculate your needs according to the new dimensions. As mentioned above, the rule of thumb is that you need 20 BTUS per square foot of livable space. However, this assumes that you live in ideal temperatures and have a completely and properly insulated house with absolutely no loss or leakage. In reality, the climate you live in will affect how much you actually need.

For example, compare these calculations for a 2,500 square foot home in various region types in the United States to the climate in your region:
  • Warm climate: 2,500 x 30 = 75,000 BTUs
  • Temperate climate: 2,500 x 40 = 100,000 BTUs
  • Cold climate: 2,500 x 50 = 125,000 BTUs
  • Very cold climate: 2,500 x 60 = 150,000 BTUs
As you can see, 30 to 60 BTUs depending on your average temperatures is closer to the mark. This accounts for leakage in ducting and less than perfect insulation. It also accounts for people entering and leaving your home throughout the day.

Remember that the BTU number only reflects the amount of energy it will take for your system to raise or lower 1 pound of water by 1 degree Fahrenheit. It does not reflect the actual amount of heating or cooling going into your house.

Other factors that can affect what size unit you should get include:
  • Foundation type
  • Type of roof
  • Color of the roof
  • Insulation values
  • Windows (type, location, and number)
  • Exterior doors
  • What temperature you want to maintain
  • Where you live
  • Size of the house
  • Which way the house is facing
  • Construction materials used when the house was built
  • Landscaping that can affect how much sun or wind hits the house
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.

You should also consider various upgrades to your HVAC system.
  • Variable Speed Fan - A standard motor has two speeds: "on" and "off". This means that the fan is blowing 100% for the entire time that it's on. A variable speed fan can save energy by blowing more slowly to maintain temperatures, going up to full speed only when it must.
  • Whole-house Humidifier - Temperature is only part of the way an HVAC system makes your home more comfortable. A properly running system will maintain humidity, but you may be more comfortable or have medical conditions that require higher or lower humidity levels than your standard HVAC system can provide.
  • Whole-house Zoning - With this option, you can control the temperature for each room. By zoning, you can have your heating and cooling system shut off the conditioning in rooms that don't need it while focusing on rooms that do.
  • UV Lights - UV lights are useful for controlling germs. A UV light sanitizes the air from germs and mold spores just like the systems used in hospitals.
  • Ventilation - A ventilation system takes a more active role in removing stale air from your home. It pumps old air out and brings new air in.
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Energy Efficiency

Energy efficiency is one of the big draws when it comes to deciding to buy a new HVAC system. If your system is more than seven years old, it's probably time to check it for efficiency.

Energy Star Certification

You've probably noticed many appliances boasting an Energy Star Certification. What this means is that manufacturer voluntarily built the product to help reduce greenhouse gases and meet non-regulatory guidelines offered by the Environmental Protection Agency. To earn an Energy Star rating, a product or system must be tested by a third party that has been recognized by the EPA for meeting their testing qualifications.

New homes can also be Energy Star Certified. These are tested according to one of two "paths". The "Prescriptive Path" uses a predefined list of improvements. The "Performance Path" looks at a customized list of upgrades. Both paths call for the completion of four checklists:
  • Thermal Enclosure System Rater Checklist -- This checklist examines windows, doors, and skylights for placement and how well they perform against leaking.
  • Water Management System Builder Checklist -- This checklist examines a house for moisture control.
  • HVAC System Quality Installation Rater Checklist -- This checklist makes sure the system has correct ducting, proper running of lines (for example, ductwork may not run along the inside of a wall without proper R6 insulation), and that the system is of the correct size for maximum efficiency in heating and cooling the house.
  • HVAC System Quality Installation Contractor Checklist -- This checklist identifies all of the steps the contractor has taken for the Energy Star Certification and identifies what work the contractor has done. If the system is later modified, this checklist can help identify what was done to proper Energy Star specifications and what was added later that may not meet the requirements.
What the Energy Star Certification means for the consumer is that the product or home surpasses the 2009 International Energy Conservation Code, which calls for a 15% increase in efficiency. The Energy Star Certification attests to twice that, for a 30% increase in efficiency!

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SEER

SEER is useful for comparing one model to another much in the same way that a car's calculate MPG is useful. It's not an accurate prediction of exactly how efficient the system is, but it can tell you which one is more efficient. Also, since SEER is based on a "cooling season", what region you live in will determine how long or short your cooling season is.

The average yearly cooling cost in the United States is about $251 per year at 13 SEER. Over that period, let's compare the various SEER ratings based on the US zones:

Zone 13 SEER* 14 SEER 16 SEER18 SEER19 SEER20 SEER
1 $251 $233$204$181$172$163
2 $401 $373$326$290$275$261
3 $602 $559$489$435$412$391
4 $852 $792$693$616$583$554
5 $1203 $1117$978$869$823$782

*In 1992 the Department of Energy established 13 SEER as the minimum efficiency allowed. Systems built before 1992 are 10 SEER or lower.

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Maintenance

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.
  • Replace the filter: Learn your manufacturer's instructions for cleaning or replacing your filters. Never run the system without the filters in place, and always let a washed filter dry completely before reinstalling it.
  • Once a month clear any leaves or debris from outdoor condensers. This is especially crucial during the summer months.
  • 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.
  • Inspect the fan blades: If your fan has been making a clicking noise that means it's been striking something. If your blade has bent, don't try to straighten it. It could have become unbalanced and will only cause more problems down the line. Replace the blade.
  • Maintain a 2 foot clearance around your unit. Don't let any vegetation grow near it as it could obstruct the HVAC's ability to "breathe". If you have a lawn near the unit, make sure any grass cuttings fly away from it. During autumn, be sure to keep leaves away from the fan grill.
  • Lubricate the condenser fan motor: If there are oil ports, they will be covered with rubber or metal caps. 10 drops of SAE 20 oil per port is sufficient.
  • Shade the compressor unit: If possible, have some kind of shading over it to keep the air temperature around it 5 to 6 degrees cooler than the unshaded air.
  • Have a form-fitting cover for the winter months: Do not run the unit when it's colder than 60 degrees outside.
  • Clean the indoor evaporator coil: Remove the front panel of your heating unit. Using a soft brush attachment on a vacuum cleaner gently clean any dust off of the coil. Inspect the fins, making sure they're straight. If any are bent, a fin comb can be bought at any refrigeration supply dealer.
  • Clean the drain pipe and evaporator trap: Flush the trap with water and then disinfect with one tablespoon of bleach.
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Rebates and Warranties

Warranties

HVAC warranties will vary from manufacturer to manufacturer. Most require that you register your system to receive the benefits of a warranty. In general, you should have 1 to 2 months to fill out and return your warranty registration.

The base warranty for most HVAC systems is 5 years with the heat exchanger warrantied for 10 years. A registered limited warranty effectively doubles the length of warranty to 10 and 20 years respectively. The warranty covers:
  • Coils
  • Exchangers
  • Compressors
  • Humidifiers
  • Manufacturer-provided thermostats
  • Internal components to these items
The warranty is usually only for the original purchaser of the system and is not transferable.

What isn't covered is replacing parts that are specifically designed to work with an older, no-longer-allowed refrigerant. As of January 2010, for example, federal regulation banned R-22 refrigerant. Parts that are not compatible with R-410A refrigerant are not covered under warranty for replacement.

Also generally not covered by the warranty are:
  • Shipping costs for replacement parts
  • Labor costs for repairs and/or diagnostics
  • Failures caused by third-party parts or use of the system in a non-prescribed manner
  • Parts bought over the internet but not from the manufacturer
  • Installation not performed by a qualified installer
  • Cabinet pieces that do not affect product performance
  • Filters, fuses, and other consumable parts
  • Increased utility costs
Warranties can be voided by the following:
  • Failure to register the warranty in the time specified by the manufacturer
  • Improper installation not performed by a qualified HVAC technician
  • Off-brand replacement parts
  • Improper maintenance. Some manufacturers require routine professional maintenance or your warranty will be void.
Again, these can change from one manufacturer to another, so be sure to read your fine print.

Rebates

With an HVAC system, rebates are often quite substantial. Some government rebates can total up to $1700 for going with a high-efficiency, zoned, solar-powered model.

At the state level the rebates are still substantial. For example, switching to a zoned system can get you a $100 rebate from various A/C companies, and state rebates are also included. In Pennsylvania a high-efficiency air conditioner alone can get you up to $300, and a high-efficiency complete HVAC system can see up to $1000. Maryland's incentives get up to $1,250, with a $100 rebate on a tune up of an existing system.

Finally, check with the manufacturer if you're buying the system yourself. Many of them offer rebates on top of the state and federal rebates. Carrier, for example, offers up to $1450 rebates through their authorized dealers.

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