If you’ve been house hunting you realize many homeowners don’t know the age of their heating and cooling system.  Maybe it was there when they bought the house.  Perhaps they know its age and just don’t want to tell you how old it is. It’s always wise to be able to determine the age of the system for yourself. Since the HVAC system is the most expensive system in the house – more costly than the electrical or plumbing systems – it is important to determine the system’s age so you can estimate how long it will last.  You’ll also know how to structure any offer you make based on what you’ll expect to spend in the near future for repairs or replacement of the HVAC system.

So how do you discover the age of an HVAC system when looking at homes? This guide provides answers.

Determining the Age of an HVAC System

The first thing to do is to examine the furnace or the air handler.  On the cabinet of the furnace, or inside the cover, you may find a metal plate that provides you with the information you need.  Some of these plates give the manufacturing date of the furnace or air handler, which makes it quite easy.

If the manufacturing date is not present, you may find a serial number for the furnace.  Jot down the brand name and all the numbers you find on the plate.  Then call a local dealer for that brand of furnace or air handler.  They should be able to look up the year of the furnace using the information you give them.  It’s the same information they use to determine dates in order to select the right replacement parts for HVAC systems.

If there are no numbers, which is unlikely, note the brand and model name of the furnace.  That will give the local dealer a ballpark idea of the age of the furnace.

Checking the Age of a Split HVAC System

If the HVAC system uses an indoor furnace, be sure to do the same examination of the outside condensing unit, if it has one. In many homes, the furnace and the central air conditioner or heat pump were not installed at the same time.  It’s possible that the air conditioner was added later.  It may also be that the furnace was replaced but not the air conditioner, meaning the AC may be older.  Find the manufacturing plate on the condensing unit and do the same investigative work to determine the unit’s age.

Protecting Yourself Against an Old HVAC System

If you’re concerned about the age of an HVAC system, consider hiring the local contractor for that brand to look it over.  He or she can evaluate its condition and tell you how long they think it will last. An inspection typically costs $50-$125, and you’ll have to pay that out of your own pocket.  If there are significant concerns, give up on that house.  Or, you might consider dropping your potential offer to reflect HVAC replacement sooner rather than later. Another option is to ask the seller to buy a 3-year home warranty that covers the HVAC system so that you know you won’t have to invest money in it immediately.

Finding out the age and condition of the HVAC system is an important part of house hunting.  Thinking the HVAC system is in good condition when it’s not can be a costly mistake.  This guide will help you determine the age of the HVAC system when looking at houses and to make a good decision in response.

Many of us are looking for ways to reduce the environmental impact of our lifestyle.  For starters, we can heat and cool our homes in a cleaner, more energy-efficient way.  Here are the best ways to “green” your HVAC system.

1. Choose the Most Efficient System you can Afford

The less energy you use to heat and cool your home, the fewer greenhouse gases are produced and released.  If you are in a position to upgrade your system, look for efficient components.  Choose components with efficiency levels that are at least Energy Star qualified.  For air conditioners and heat pumps, that is 14.5 SEER.  However, there are heat pumps available with 20 SEER ratings and higher.  For gas furnaces, 90% efficiency is the minimum standard.  You can find gas furnaces that are 95% efficient and higher.  Choose the Energy Star models that match your budget.

2. Choose Products that use R-410A Refrigerant.

Most Energy Star air conditioners and heat pumps are now being manufactured with R-410A refrigerant, but it doesn’t hurt to be sure.  This refrigerant is sometimes referred to by one of its brand names such as Puron (Bryant/Carrier) or SmartCool 410 (Maytag).  It does not contain chlorine, a chemical known to damage the ozone layer which might increase global warming.

3. Keep your HVAC System Cleaned and Maintained

Even if you can’t replace your HVAC system right now with a newer, more energy-efficient one, you can make it greener by having it cleaned and maintained.  A poorly maintained HVAC system will lose efficiency – as much as 30% efficiency. This will waste money and also produce far more carbon emissions than needed.  Have an HVAC professional clean an older system immediately and then keep your HVAC system in good condition.  It should be serviced by the HVAC company every 1-3 years, depending on how heavy it is used.  If you have a new system installed, keep it maintained according to the manufacturer’s recommendations to ensure the highest, most environmentally responsible efficiency possible.

4. Fix Leaky Ductwork

The ductwork is an important part of your HVAC system, circulating treated and untreated air through the system and into your home.  Leaks in the ductwork can waste up to 20% of the heating or air conditioning, and that adds up.  Seal the ductwork with mastic or professional-grade, foil-faced duct tape.

5. Insulate your Home Properly

Having an adequate amount of insulation in your attic will significantly reduce how much heating and cooling the system has to produce.  You can reduce energy use and impact to the environment by as much as 15% by increasing the amount of insulation in your attic and anywhere else it can be added.

6. Have your New HVAC System Properly Installed

If you do choose a new system, make sure it is installed by a qualified contractor with good training, skills and experience.  Take time to adequately screen the HVAC companies you are considering or use a service that pre-screens them for you.  To run most efficiently, a heating and air conditioning system must be installed the right way.  If not, it will waste energy every month, undermining your commitment to a greener HVAC system and lifestyle.

For many homeowners, the HVAC installer they choose is an afterthought.  Their focus is on the level of energy efficiency and the performance features they want. Once they’ve decided on an HVAC system, they give the job of installing it to the heating and air conditioning company with the lowest price.  Finding a good price is always important, but getting cheap installation from a company that doesn’t do a good job will end up costing you in the end.  Always get multiple estimates, but price shouldn’t be the only thing you look at when considering which estimate to accept.

Here are the top 3 reasons to choose a quality installer for your HVAC system.

1. Properly Installed HVAC Systems are More Efficient

Today’s heating and air conditioning systems are complex. They typically consist of a furnace and a central air conditioner, a heat pump and an air handler, or in dual fuel systems, a heat pump with a furnace. A heat pump or air conditioner has a separate coil which must be housed within or on top of the furnace or air handler.  The entire system needs to be installed and set up to work in synergy.  When the installation isn’t precise, a system can run at 10%-30% below the efficiency level it should achieve.  That’s like turning a 90% efficient furnace into a 70% furnace or a 16 SEER heat pump into a 12 SEER model.  It’s a huge waste of money.  Whatever is saved by going cheap on the installation will be lost in just a few years through utility bills that are higher than necessary.

2. Properly Installed HVAC Systems are Safer

The potentially dangerous failures that can go wrong with an HVAC system are significant.  Faulty wiring at the unit or at the electrical box can result in damaged equipment or worse, a house fire.  A gas line improperly installed can lead to an explosion and fire.  A leaking or blocked furnace vent can release deadly carbon monoxide into your home. These are some of the most common causes of accidental injury and death every year.  The dangers are just too great to have the job done wrong.

3. Properly Installed HVAC Systems Perform Better and are More Durable

This really begins before installation.  The HVAC contractor needs to assemble a system that is the right size for your home and is designed to work together.  About size, HVAC components are built with different capacities to meet the heating and air conditioning needs of different homes.  Most often, the right size system is determined by a complex formula known as a load calculation or a heat loss calculation.  If a system is too small, it won’t adequately heat and cool.  If it is too large, it will waste energy and be prone to mechanical problems from running on short cycles.  A good contractor will do what is necessary to choose system components with the right capacity for your home.

As far as working together, the components must match.  For example, if you choose a 3 ton central air conditioner, the blower motor in the furnace must be a 3 ton blower.  The same 100,000 Btu furnace model might come with a 3-ton fan or a 4-ton blower.  If you get the wrong one, it won’t circulate the air correctly, leading to unbalanced temperatures in your home and possible mechanical issues too.

Summary

So how do you find the right installer for your HVAC system?  Ask others who they’ve used and get recommendations.  Read sites that have contractor reviews on them and jot down the names of highly-rated companies. Choose a system that offers free estimates from pre-screened local HVAC companies.  Get at least 3 estimates and during the process, ask plenty of questions about training and experience.  Choose the qualified contractor who you believe has the skill and professionalism to do the job the right way the first time.

Homeowners often want to know what are the best HVAC systems available.  There are really 2 approaches to answer that question and both are very important.  From a ratings standpoint that addresses the overall quality and performance, the best HVAC systems are those that combine high efficiency with precise control of indoor air quality.  That's one way to look at the issue.

A second, and equally valid way of describing the best HVAC systems is to discuss which one is the best one for your specific use.  In some cases, the answer to the question might be the same for some homes either way you approach it.  In others, primarily from a cost-efficiency standpoint, the top of the line models might not be the best choice.  Let's address the best HVAC systems from both angles.

The Top Rated HVAC Systems on the Market
When consumer HVAC reviews and independent tests are compiled, there are a handful of HVAC systems that stand out as being the best available.  Here's a list of the 5 best HVAC systems with a brief note or two.
1. Carrier Infinity Series: This has been the premier HVAC system in the industry for some time and it continues to be the choice of those who want the very best.  High efficiency is coupled with outstanding indoor comfort, driven by the Infinity touchscreen programmable controller.

2. Trane XLi Series: Several efficiency levels are offered and the performance is excellent, assisted by 2 compressors to give your home the smooth operation or the cooling/heating boost required.  This system is the top competition to the Carrier Infinity.

3. Dave Lennox Signature Series: This is the flagship line from one of the most respected names in the industry. High performance is offered in the air conditioners, heat pumps and furnaces that make up this high-quality lineup.

4. American Standard Platinum Series: The series offers a choice of efficiency levels to choose from so you can match your needs to your climate. The comfort control is outstanding, with minimal temperature fluctuation. Humidity-control, air filtration and home ventilation products are also part of the series.

5. Maytag 1200 iQ Drive Comfort System: The standout performers in this series are the air conditioners and heat pumps that are among the most efficient on available.  They feature a modulating compressor that delivers the most precise and efficient way to get the indoor comfort you want.

For top of the line quality, these are the best HVAC systems to consider.

Choosing the Best HVAC Systems for Your Home
For many homeowners, the right HVAC system is the one that best accomplishes their goals which may include reducing energy consumption and utility bills,  producing the most comfortable indoor climate, or doing an adequate job of heating and air conditioning while keeping equipment costs as low as possible.

As you can see, these goals can be mutually exclusive. The systems with the highest efficiencies and best performance will not be the ones that offer the lowest equipment costs.  The most affordable systems will not offer the greatest indoor comfort.

Here are some factors to consider as you select from among the best HVAC systems for your home.

1. In very warm or cold climates, high-efficiency equipment will be more cost-effective for long-term use.  You'll pay more for higher efficiency levels but the reduction in your energy bills will pay you back in just 3-5 years, and then the savings will be money in the bank.

2. In moderate climates -- think San Diego, Northern California, the Pacific Northwest, mountainous areas in southern regions -- the most cost-effective equipment will be lower-efficiency equipment.  The payback period if you buy a very high-efficiency HVAC system might be 10 years or more.  There are systems, including in some of the specific series mentioned above, that offer good but not great efficiency while still offering top comfort.  The least efficient equipment in the Lennox Signature or Trane XLi series, for example, might provide a good combination of lower equipment costs and excellent climate control.

3. The best HVAC systems for advocates of a green lifestyle will be the most efficient systems they can afford, regardless of where they live.

4. For those looking for a 1-5 year HVAC solution -- those planning to move in that time period, for example -- than the best HVAC systems will be the least expensive systems that still offer reliable quality.

5. Homeowners who want lower utility bills and are content with single-stage heating and air conditioning will choose basic HVAC systems with 15-17 SEER ratings and furnaces that offer efficiency in the low-90% range.

Conclusion
As you read through this, you've got the question answered both ways.  We feature information on all of the series mentioned above, from Carrier, Trane and the others.  See the appropriate posts for the details that will help you choose the right one.  Modify your decision-making as you consider the best HVAC systems for your home and you'll be able to choose one that meets your specific needs.

HVAC installation cost for most systems can account for 40% to 60% of most jobs.  By installation, we mean the labor cost to place the HVAC components, connect them, adjust them and get them running properly.  If we also included in the HVAC installation cost additional materials required to complete the job, then installation might account for as much as 80% of the job or more!

Our purpose here is to break down the factors that enter into HVAC installation cost including the HVAC components, additional equipment, and the cost of labor.
HVAC Components Cost
We're discussing complete HVAC systems which would include air conditioner and gas furnace split systems, heat pump split systems with either an air handler or a gas furnace, and package units.  There is a wide range of possible costs for the HVAC components. The price goes up as size and efficiency increases.  It also rises with performance features such as communicating technology, high-tech thermostat, 2-stage or modulating heating and cooling, a variable-speed blower and low-noise operation.  Some brands cost more than others, even when the size, efficiency and features are the same.  This may be due to a better track record for reliability or it may simply mean that the brand has a better reputation whether it is earned or not.

If we were to break down an average system, for example a 3 ton central air conditioner with a 100,000 Btu gas furnace, these cost samples will give you an idea of what you'll pay for the equipment.

Standard efficency (80% AFUE) and basic features: $2,400 to $3,200

High efficiency (90% to 95% AFUE) and some performance features: $3,000 to $5,000

Very high efficiency (above 95% AFUE) and top performance features: $5,500 to $8,500

HVAC Installation Cost
There is even more variance here in costs.  These are the factors that will affect the total HVAC installation cost.

1. Minor additional sheet metal like a new sheet metal plenum for connecting the furnace or air handler to existing duct work might increase the cost by $100 to $400.

2. Minor additional venting materials might increase the cost by $50 to $200.

3. Additional refrigerant line or gas line might increase the cost by $100 to $400.

4. Removal of an old gas furnace, condensing unit or package unit might increase the cost from $200 to $600.

5. Replacing duct work is the most expensive "extra" and might increase the cost by $1,000 to $10,000 depending on the size and complexity of the house.

HVAC Labor Cost
Some contractors will provide an itemized estimate that shows the cost of the equipment, the materials and the labor for the installation of a new or replacement HVAC system.  Labor rates vary based upon the cost of living in your area, the size of the crew doing the work, as well as the competition among HVAC contractors.

On average, expect the labor portion of the HVAC installation cost to be between $125 and $200 per hour.  Though it might be called labor costs, it really includes wages, benefits, workers compensation insurance and liability insurance, tools, facility and vehicle overhead, and yes, some profit built into the estimate.

Other Factors Affecting the HVAC Installation Cost
In general, the more complex the installation is, the more it will cost.  For example, if you want a package unit installed on a roof, it will cost more than installation on a pad next to your home's foundation.  If you need a furnace installed in a cramped attic or crawl space, it will cost more than having it installed in a roomy first-floor utility closet.

Finally, HVAC installation cost is affected by how busy the contractors are.  In other words, don't expect a contractor to be willing to flex much on price in during the hottest stretch of summer or coldest months of winter.  When they've got all the work they want, they'll write their estimates for full price.  However, when business is slower, depending on your region of the country, contractors are often willing to estimate or negotiate a lower HVAC installation cost in order to keep business steady.

If your furnace quits in the middle or winter or your A/C fails in July, there may not be much you can do about this factor.  However, if you are choosing to replace a working system because it is old or inefficient, it might make sense to get bids during slow seasons in your area.  Those estimates will likely be much more competitive.  Don't hesitate to make counter offers either, in order to negotiate the best possible HVAC installation cost for the work you need done.

Conclusion
It is easy to see how installation can be so expensive, often forming a larger portion of the total bill than the HVAC equipment.  The costs we have outlined above will help you understand what to expect when getting HVAC installation cost estimates from  contractors in your area.  We recommend getting at least 3 estimates in order to find the right contractor at the right price.

Remember that the quality of the installation is an important part of how well your HVAC system will perform in the years ahead, including how long it will run before needing repairs or replacement.  The lowest estimate may not be the best long-term value.  Choose a contractor you believe will do a good job and then pursue the lowest HVAC installation cost you can.

To determine the proper size HVAC system for your home, a load calculation must be done.  This ensures that the unit will be large enough to adequately heat and cool your home but not be so large that it wastes energy, does a poor job removing humidity during cooling, or leaves hot and cold areas in your home.

Most HVAC professionals use the Manual J load calculation developed by the ACCA, the Air Conditioning Contractors of America.  It contains a complex HVAC calculation formula that is actually a series of smaller calculations. The purpose of the calculations is to determine how much treated air -- either heated air or cooled air -- is lost from the home due to its construction materials.  The square footage of the home is also a factor.

If a home were perfectly insulated, once it was adequately warmed or cooled, it would no longer require additional heating or air conditioning.  While that is not possible, it serves as the baseline for determining the load calculation for the home.  The purpose is to find out how much additional treated air is required to maintain the ideal indoor air temperature given the fact that warmth escapes from the house during the winter and heat from outside warms the house during the summer.  The escaping of heat or the influx of heat causes the HVAC system to work.

While a comprehensive understanding of the HVAC calculation formula would be well beyond the scope of this guide -- there are entire software packages dedicated to it, and the Manual J is quite thick -- we can at least look at the basics of heat gain and loss within a home.  This is the amount of heat that seeps into the home while the HVAC system is working to keep it cool.  The science works the same for heating -- the same equation will show how much heat is lost when the HVAC system is in heating mode.

The Basic HVAC Calculation Formula
Heat gain and loss are determined with the use of this equation: Q = U x A x DT.

Q = Heat gain or loss in Btu/h, or British thermal units per hour.

U = Thermal transmittance through the roof or wall in Btu/h/sq.ft/F, or Btu's gained or lost through the roof or wall per square foot at a certain temperature F, or Fahrenheit.

A = Area of the roof or wall in square feet.

DT = Temperature difference in F between the inside air and the outside air.

If it can be determined how many Btu's of heat are being gained or lost through 1 square foot of roof per hour, it can then be calculated how much is lost in an hour given the square footage of the entire roof.  This answer is determined by factoring in the amount of insulation above the ceiling, what type of material is on the roof, what direction the roof sections face, and more.

For walls, the determination of heat gained or lost through the walls factors in the number and quality of windows, whether or not the windows have shades or awnings, the amount of insulation in the walls, and the type of material is found on the outside of the home.

In the Manual J, there are tables that give the value of U in the equation based upon the insulation R-factor of walls and roofs, roof and wall construction, the windows and siding material, and additional factors that are entered into the final HVAC calculation formula.

Additional Factors
A proper HVAC load calculation also considers factors not related to construction. These include the number of people who live in the home, the amount and type of lighting and the number and types of appliances in the home.  All of these factors add heat to the home and make it easier to heat and harder to cool.

Conclusion
The equations involved in an HVAC calculation formula are analyzed to determine the heating and air conditioning capacity required by the system.  Be sure that your HVAC professional does a load calculation so that you can have the confidence you've got the right size heating and air conditioning system to keep maximize energy efficiency and indoor comfort in the years ahead.

Terms

Getting familiar with the terminology is an important part of an introduction to HVAC systems. We’ve listed the terms logically rather than in alphabetical order.

HVAC: This stands for Heating, Ventilation and Air Conditioning.

Condensing unit: The main component in a central air conditioner or heat pump.  It contains a compressor that pumps refrigerant, a condensing coil and a fan, along with supporting parts.

Refrigerant: A substance with the capacity to expand and absorb a significant amount of heat and then rapidly condense and shed that heat.  Refrigerant cools a home by absorbing and removing heat, and heats a home by absorbing heat outside and releasing it inside.  Refrigerant is used in both central air conditioners and in heat pump systems.

Heat pump: A condensing unit is usually associated with central air conditioning because it uses refrigerant to pull heat out of the home, thereby cooling the home.  A heat pump contains a condensing unit that also heats the home.  The flow of refrigerant is reversed.  Heat is captured outside and released by the refrigerant indoors.

Air handler: An HVAC component installed inside a building that pushes treated (heated or cooled) through the supply ducts and pulls untreated air into the system through the return ducts.  It does not produce heat.

Efficiency: This term refers to how efficiently the HVAC equipment uses its energy source to heat or cool air.  For condensing units, the efficiency is measured in SEER (Seasonal Energy Efficiency Rating) for air conditioning and HSPF (Heating Seasonal Performance Factor) for heating. In both cases, the higher the number is, the more efficient the unit is.  For gas and oil furnaces, efficiency is measured by AFUE (Annualized Fuel Use Efficiency), and is given in a percentage.  For example, in an 80% AFUE furnace, 80% of the heat created goes into the home and 20% is wasted in the venting process.  Today’s most efficient furnaces are more than 97% efficient.

Capacity: This is sometimes referred to as the “size” of a unit and refers to how much heating or air conditioned air a unit is capable of producing.  Condensing units are measured by tons, a reference to the cooling capacity of one ton of ice.  Residential condensing units are produced with capacities from 1.5 tons to 5.0 tons.  Their heating capacity is measure in Btuh, or British thermal units per hour.  One ton of cooling capacity is equal to approximately 12,000 Btuh.  Furnaces are measured by Btuh.

Types of HVAC Systems

This introduction to HVAC systems wouldn’t be complete without a discussion of the types of HVAC systems available.

Split system: An HVAC system in which a condensing unit or heat pump is installed outside the home and a furnace or air handler is installed inside.

Mini split system: An air conditioning system in which a small condensing unit is installed outside and up to 4 small evaporator units/air handlers are installed in rooms or zones.  These are also called ductless systems because they disperse air through the evaporator unit rather than through the building’s ductwork.  They are popular installations where no duct work exists.

Packaged Unit: Unlike a split system, both the heating and air conditioning components are housed in one large cabinet, installed outside the home or building.  There are several types of packaged units.  Gas packaged units, also called gas/electric packaged units or simply gas packs, use a furnace to heat and a condensing unit to cool.  Heat pump packaged units use a condensing unit to both heat and cool.  Air conditioner packaged units use a condensing unit to cool but have no source of heat.  They are used in residential settings where an alternate form of heating is used, and in commercial buildings in warm climates.

Keys to Cost

We’ll conclude this introduction to HVAC systems with a brief discussion of the major factors that affect cost.  In order of importance, they are:

1. Efficiency:  High-efficiency HVAC systems cost more for the equipment, but they use less energy and so produce reduced utility bills.  You’ll need to decide if purchasing high-efficiency equipment makes sense in your situation based on your area’s climate and how long you intend to stay in the home.

2. Capacity: The greater the volume of air that can be treated, the more the unit will cost, all else being equal.

3. Performance features: Certain features optimize the homeowner’s ability to precisely control indoor climate.  These include a 2-stage compressor in a condensing unit, multi-stage gas valve in a furnace, and a variable-speed blower in an air handler or gas furnace.  They are attractive to those who want very even temperatures with little fluctuation, but they also allow better humidity control in all seasons and better air filtration or purification.  This is primarily because they operate on low most of the time, and so they run more consistently.  Air circulates more continuously to achieve these desirable results.

Conclusion

While this introduction to HVAC systems isn’t exhaustive, it will give you the information you need to understand the basics of today’s heating and air conditioning systems.  The more information you have, the more likely you are to make decisions you’ll be satisfied with in the years to come.

We’ll begin by discussing the major components you’ll need to know about for understanding HVAC systems.  The term HVAC outlines our approach: Heating, Ventilation and Air Condition.  We’ll look at heat sources, air conditioning sources and the role of ductwork in how HVAC systems work.

Air Conditioning

Here is an overview of how central air conditioning works to cool your home.  The condensing unit is the large cabinet that sits outside your home.  It contains a compressor, a condensing coil, a fan and other supporting parts.  Inside your home, in the furnace or air handler, you’ll find the evaporator coil.  A copper refrigerant line carries liquid refrigerant into your home and is attached to the evaporator coil. There, the refrigerant rapidly expands into a gas, absorbing heat in the process.  The result is that the coil gets very cold.

The hot gas refrigerant leaves your home via a second copper line attached to the condensing coil where the refrigerant is condensed back into a liquid, shedding heat in the process.  The condensing coil is similar to a radiator.  Heat transfers through it very efficiently and is dispersed by the condensing unit’s fan.

Back inside your home, the furnace’s blower motor starts to run, passing warm air from the house over the cold evaporator coil, cooling it significantly as the refrigerant absorbs heat out of it.  The cooled air is forced through the supply ducts into your home.  This cycle continues until your home is cooled to the level indicated on the thermostat.

Heating Components

The 3 most common heating components in use today in residential settings are the gas or oil furnace, the electric furnace, and the heat pump.

1. Gas or Oil Furnace: These heating components have certainly stood the test of time.  They are affordable, efficient and clean-burning.  Here is how they heat your home.  When the thermostat calls for heat, a draft inducer motor starts.  It is smaller than the blower motor.  Its purpose is to ensure that the furnace vent is open so that combustion gases may escape.

If the vent is open, the fuel valve will open so that oil, natural gas or propane can flow into the burner.  Oil burners and gas burners function slightly differently, but the effect is the same.  The fuel is ignited and begins to heat the air in the combustion chamber.  A fresh-air supply feeds the flame.  The combustion gases never mix with air being distributed into your home.  They pass through a heavy-gauge metal component known as a heat exchanger.  The purpose is for heat to transfer through the metal and heat the air that is being cycled through the ductwork.  The combustion gases are vented through the flue after passing through the heat exchanger. High-efficiency furnaces contain a second heat exchanger that captures even more heat before it is vented.

Once the flame is burning, the furnace’s blower motor starts.  It pushes heated air through the supply ducts into rooms or zones of your home.  At the same time, it draws unheated air into the system via the cold-air returns.  This cycle continues until the temperature in your home reaches the level set on the thermostat.

2. Electric Furnaces: These work similarly to a gas or oil furnace but they use electrically powered heating coils instead of gas or oil.  This simplifies their installation and means that no fuel lines or fuel storage tanks are required. The heating coils heat air that is dispersed by a blower through the ductwork.

3. Heat Pump: To understand how a heat pump warms your home, first read the section above on air conditioning.  Heat pumps contain a reversing valve that changes the directional flow of refrigerant.  This means that heat is captured outside your home and brought in by the refrigerant to be released inside the indoor coil and distributed through the ductwork.  Heat pumps are effective in capturing outdoor heat down to about the freezing mark, and even a bit lower.

Heat pumps most often use an air handler to distribute the heated air.  However, many heat pumps are dual fuel compatible, meaning they can be paired with a furnace instead.  That gives the homeowner the choice to switch to furnace heat when the temperature gets too low to make heat pumps effective.

Split Systems and Packaged Units

The term “split system” is used with central air conditioner and heat pump systems when the condensing unit is installed outside your home and the furnace or air handler is installed inside.

One type of split system we haven’t mentioned is known as a mini split or ductless system.  It is a form of air conditioning system that serves a single room or zone within a home or building.  A small condensing unit is installed outside.  A single evaporator unit or mini air handler is mounted in the room or zone, usually high on a wall or on the ceiling.  They do not use any ductwork.  They cool and distribute air by drawing it into the unit, cooling it and sending it back out.

The term “packaged unit” is used when all the major components of the HVAC system are packaged together and installed outside your home in one large cabinet.  There are gas packaged units that use a gas furnace for heating, heat pump packaged units in which a heat pump does double duty, and air conditioner packaged units that supply cool air only.  One duct connects to the home and supplies treated air (heated or cooled) and a second duct brings untreated air to the system.

Conclusion

Understanding HVAC systems is a matter of knowing how they produce treated air.  Our goal is to help you be a knowledgeable consumer who can take control of your heating and air conditioning decisions rather than feeling like you have no choice but to leave them in the hands of a contractor.  Educated consumers will more often make decisions that are in the best long-term interest!

The Components of a Split Air Conditioning System

To begin with, a split system means that the components are located in 2 separate areas.  In a split air conditioning system, the condensing unit is located outside the home, usually on the ground near the foundation. The condensing unit is the heart of the air conditioning system and is often simply called the “air conditioner.”  In most climates, a gas furnace makes up the second half of the split system.  It is typically located in the basement of the home, or perhaps the attic or a first-floor utility closet.  In very warm climates, or in homes that use an alternate form of heating such as a wood stove, the furnace may be replaced by an air handler that circulates air through the home but does not produce heat.

The furnace or air handler also contains the indoor coil, also known as the evaporator coil, which is an essential part of the cooling system.  The third important component of a split air conditioner system is the home’s ductwork which must be sized correctly to match the capacity of the blower in the furnace or air handler.  Now let’s look at how this system heats and cools your home.

Heating your Home

Let’s start with heating.  The gas furnace starts up when the temperature in the home drops below the setting on the thermostat. The first sound you’ll hear is the draft fan blowing air up through the vent or flue to determine that the passageway is open.  Then a hot surface igniter begins to heat up.  The gas valve opens and gas enters the burner.  It is ignited and begins to create heat.  All of this happens in a sealed combustion chamber so that the heat stays in the system and no carbon monoxide or other combustion gases escape into the house.

Once the burner fires, the blower motor starts and the blower fan begins drawing cold air into the system through the return ducts.  The heated air passes, containing the combustion gases, passes through a heavy-gauge metal part known as the heat exchanger.  It radiates heat which warms the air around it.  The heated air is circulated through the home via the ductwork, pushed by the blower.  This heating and circulation of air continues until the air temperature around the thermostat reaches the desired temperature.  The combustion gases leave the home via the flue once they have passed through the heat exchanger.  High-efficiency gas furnaces use a secondary heat exchanger to effectively dissipate more heat before it can be lost up the chimney.

Cooling your Home

Here is how a split air conditioning system cools your home.  The condensing unit has a compressor that pumps refrigerant into the home via an insulated copper lineset.  The liquid refrigerant enters the evaporator coil in the furnace or air handler where it quickly evaporates into a gas.  As it expands into a gas, it rapidly captures heat from the home, effectively cooling the air around the coil.  That cooled air is then distributed through the house via the ductwork and blower, while warm air is being drawn into the system.

The refrigerant is now a gas.  It carries the heat out of the house via another copper line connected to the condensing coil.  There, it condenses back into a liquid, shedding heat in the process.  That heat dissipates quickly through the condensing coil, which looks very much like a radiator.  The released heat is dispersed by the condensing unit fan.  This cycle continues until enough heat is removed from the home to lower the temperature to the desired level.

Where to Buy a Split Air Conditioning System

Split air conditioning systems are popular because they are affordable and effective.  They are also quite efficient, too.  High-efficiency systems cost more, but because they use electricity and gas more sparingly, they are also cheaper to operate.  When you are considering the purchase of a split system, you will find wholesale HVAC prices at online locations like eBay.  Large supply companies offer their inventories there at very competitive prices.  Take a look at split air conditioning systems reviews to narrow you choices to the one that makes most sense for your home and budget.

Conclusion

Split air conditioning systems make good sense for most homes.  However, the reliability, efficiency and durability of the system is often only as good as the installation.  The components must be compatible, and they must be properly installed.  It always makes sense to have a qualified contractor help you select the right system for your home and then install it, making sure it is adjusted correctly and tested.  When properly installed, a quality split system will deliver 15 to 20 years of reliable service.

We hope this overview of the split air conditioning system helps you make an informed decision as you consider your current and future HVAC needs.

Find the Right HVAC System
It's no good to get an amazing deal on a wholesale HVAC system only to find out that it's too big, or to small, to work efficiently in your home. If you're happy with your existing system you can look for a rough equivalent or call an HVAC installer and ask what would be a similar system on today's market. You can also pay to have someone come out and size your home according to Manual J guidelines. It should take several hours for someone to size your home, so don't trust an answer based entirely off of the square footage of your home.

Decide How to Buy
Buying online is the best way to find the cheapest deal. It's quick, efficient and easy to research multiple products quickly. The only drawback to purchasing online is that many manufacturers (Carrier and Thermstar for example) will not warranty any products purchased from the internet. This doesn't have to keep you from purchasing online however. Just consider the savings you'll receive online and whether or not they overcome not having a warranty.

Price is Important but Installation is King
The first thing you want to do is make sure you can find a great local HVAC installation company or technician. Finding a great deal on a furnace is great, but it won't be worth a lot if the person who installs it does a crummy job. Most of the efficiency you get out of your furnace and air conditioner comes from the quality of the installation and duct work.  Spend some time and call several local HVAC companies and get their advice. Ask if they can give you an estimate on installation only and find out what their policy is on servicing HVAC systems not purchased through them - do they still offer a maintenance agreement?

Use Your Credits
Whether you buy through an online auction or find a local retailer who is willing to match online prices, be sure to also use your tax credits. In order to take advantage of up to 30% off you'll need to act fast. The federal tax credit program expires December 31, 2010. You'll need to have a manufacturers certificate and your wholesale HVAC systems will need to be installed by a licensed HVAC contractor. This can be a way to really save big on your next HVAC system purchase.

Buying wholesale is a great way to get a good deal no matter what kind of product you're buying. Make sure you investigate the system itself as well as the folks who will be installing it. By combining a wholesale discount with a tax rebate you could be looking at a very inexpensive wholesale HVAC system. With the right installation it will last you for many years to come.