February 18, 2017

HVAC Basics


[Special thanks to Trane for providing the following information]

Air Conditioner / Air Handler Matched Systems

– Connected to the inside cooling coil, the compressor pumps refrigerant back and forth, extracting heat and moisture from the indoors. It transfers the heat to the outdoors. Warm indoor air is blown over the indoor cooling coil, then is cooled and distributed throughout your home.

Air Handler
– Matched in capacity and efficiency rating with the air conditioner, air handlers circulate conditioned air throughout your home. An air handler contains an inside coil and a blower fan, with the additional possibility of an auxiliary electric strip heater. Trane air handlers are available with single- or variable-speed motors. Variable-speed models are known for soft starts, high humidity control features and 12 selectable levels of airflow capacity, as well as the enhanced comfort mode, the Comfort-R™ airflow system.

Air Cleaner
– An integral part of a home comfort system, filtering dust and pollutants out of the air you breathe, and keeping your rugs and home furnishings cleaner as well. Reduced pollen, dust, pet dander, smoke, etc., could help reduce allergy and asthma discomfort. A Trane CleanEffects™ air filtration system is up to 99.98% effective.

Thermostat
– The control center for your home comfort system. Trane’s digital, programmable thermostats give you precise temperature control and allow you to program your heating and cooling requirements depending upon your daily activities and schedule.

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Air Conditioner / Air Furnace Matched Systems

– Connected to the inside cooling coil, the compressor pumps refrigerant back and forth, extracting heat and moisture from the indoors. It transfers the heat to the outdoors. Warm indoor air is blown over the indoor cooling coil, where it is cooled and then distributed throughout your home.
Indoor Cooling Coil – To deliver the highest system efficiency, performance and climate control, an indoor cooling coil must be matched in size and rated with your air conditioner. Use a Trane coil with your Trane system for optimum reliability.
Furnace
– Trane furnaces are uniquely designed to provide maximum heat with minimum fuel usage. And they think for themselves. Key furnace control functions are integrated into one microelectronic system that monitors the thermostat and gas valve, ensuring precise temperature control.

Air Cleaner
– An integral part of a home comfort system, filtering dust and pollutants out of the air you breathe, and keeping your rugs and home furnishings cleaner as well. Reduced pollen, dust, pet dander, smoke, etc., could help reduce allergy and asthma discomfort. A Trane CleanEffects™ air filtration system is up to 99.98% effective.

Humidifier
– By providing the right amount of moisture and preventing dry air conditions, a humidifier can help alleviate allergy symptoms and dry skin, and also reduce static electricity.

Thermostat
– The control center for your home comfort system. Trane’s digital, programmable thermostats give you precise temperature control and allow you to program your heating and cooling requirements depending upon your daily activities and schedule.

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Air Conditioners

An air conditioner, as part of a central heating and cooling system, draws heat energy out of the house and transfers it to the outside air.

An air conditioner can change the temperature, humidity or general quality of the air. More specifically, an air conditioner makes your home cooler, by drawing heat energy out of the house and transferring that heat to the outdoors, then replacing the air inside your home with cooler air.

How it works
The air conditioner in a central heating and cooling system provides cool air through ductwork inside your home, by providing a process that draws out the warm air inside, removing its heat. In a split system, the compressor condenses and circulates the refrigerant through the outdoor unit, changing it from a gas to a liquid. The liquid is then forced through the indoor evaporator coil or cooling compartment. The indoor unit’s fan circulates the inside air to pass across the evaporator fins. The evaporator’s metal fins exchange the thermal energy with the air around it. There, the refrigerant turns from liquid into vapor, removing any heat from the surrounding air. As the heat is removed from the air, the air is cooled and blown back into the house.

From that point, the condenser or outdoor unit then turns the refrigerant vapor back into a liquid, removing any heat. By the time the fluid leaves the evaporator again, it is a cool, low-pressure gas, eventually returning to the condensor to begin its trip all over again. This process continues again and again until your home reaches the cooling temperature you want, as programmed and sensed by your thermostat setting.

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Central heating/cooling

Central heating and central cooling systems are separate things but they are matched to work together. Here’s how.

CENTRAL COOLING
The most common central cooling system is a split system, which includes an outdoor cabinet containing a condenser coil and compressor, and an indoor evaporator coil, usually installed in conjunction with your furnace or air handler . The compressor pumps a chemical called refrigerant through the system.

How it works
Once warm air inside your home blows across the indoor evaporator coil, its heat energy transfers to the refrigerant inside the coil. That transfer, in turn, “cools” the air. The refrigerant is pumped back to the compressor where the cycle begins again. The heat absorbed by the refrigerant is moved outside your home while cooled air is blown inside. Moisture that contributes to humidity is also condensed out of the air.

Your cooling system is usually combined with your central heating system because they share the same ductwork for distributing conditioned air throughout your home.

CENTRAL HEATING
Central heating systems have a primary heating appliance, such as a furnace, typically located in your basement or garage. All furnaces consist of four main components: 1) burners that deliver and burn fuel, 2) heat exchangers, 3) a blower and 4) a flue that acts as an exhaust for gaseous by-products. Depending on your situation, region and needs, you can choose from heating systems running on either gas or oil as fuel, or a hybrid packaged system that can use both fuel types.

How it works
Combustion gases are generated by the burners in your furnace and passed through a heat exchanger. Air from your home blows across the heat exchanger to be warmed. It is then blown through a system of ducts to distribute around your home. During warm seasons your heating system works with your central air conditioning. Air is cooled as it’s blown over your air conditioning unit’s cooling coil, often attached to the air circulating fan of the furnace, and then sent through the same air ducts throughout your home.

Your local Trane Comfort Specialist can help you decide which central cooling and heating system is right for you. Trane matched systems can be customized with cooling and heating units that match your situation and let you choose from a range of energy efficiency.

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Ductless systems/cooling

Ductless systems connect an outdoor unit with an indoor unit to heat or cool one specific zone of a home without the use of ductwork.

COMPONENTS OF A DUCTLESS SYSTEM
Installing a ductless system is not only easy, but it allows for flexibility in where you deliver heating and cooling in your home without the use of ductwork. An outdoor unit is placed outside your home–often at ground level, but not always–and is connected to an indoor unit by small cables and a refrigerant line through a hole in the wall. The indoor unit is typically mounted high on the wall of the room and can be pre-set to run automatically or be adjusted by a remote control.

MINI-SPLIT VERSUS MULTI-SPLIT
The mini-split ductless system controls one room or zone by connecting one outdoor unit to one indoor unit. A multi-split ductless system can connect one outdoor unit to up to five indoor units – depending on the indoor and outdoor model – letting you control the heating and cooling in several zones or rooms independently of each other.

WHERE DUCTLESS IS NEEDED
A ductless system is a great solution for homes without a central heating/cooling system or when a room is added onto a house or an attic is converted to living space. Instead of extending the home’s existing ductwork, a ductless system can provide efficient heating and cooling at a lower operational cost.

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Heat Pump/Air Handler Matched Systems

Common in the South and warm, humid areas, a heat pump and air handler system is one of the many options for a matched system.

– Unlike a furnace, a heat pump doesn’t burn fuel to make heat. It simply uses electricity to move heat from one place to another. A heat pump is an energy efficient way to cool your home in the summer and heat it in the winter.

Air Handler
– Matched in capacity and efficiency rating with the heat pump, air handlers circulate conditioned air throughout your home. An air handler contains an inside coil and a blower fan, with the additional possibility of an auxiliary electric strip heater. Trane air handlers are available with single, multi or variable-speed motors. Variable-speed models are known for soft starts, high humidity control features and 12 selectable levels of airflow capacity, as well as the enhanced comfort mode, the Comfort-R™ airflow system.

Air Cleaner
– An integral part of a home comfort system, filtering dust and pollutants out of the air you breathe, and keeping your rugs and home furnishings cleaner as well. Reduced pollen, dust, pet dander, smoke, etc., could help reduce allergy and asthma discomfort. A Trane CleanEffects™ air filtration system is up to 99.98% effective.

Thermostat
– The control center for your home comfort system. Trane’s digital, programmable thermostats give you precise temperature control and allow you to program your heating and cooling requirements depending upon your daily activities and schedule.

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Heat Pump / Air Furnace Matched Systems

Common in the South and warm, humid areas, a heat pump and furnace system is one of the many options for a matched system.

– Unlike a furnace, a heat pump doesn’t burn fuel to make heat. It simply uses electricity to move heat from one place to another. A heat pump is an energy efficient way to cool your home in the summer and heat it in the winter.

Indoor Cooling Coil
– To deliver the highest system efficiency, performance and climate control, an indoor cooling coil must be matched in size and rated with your heat pump. Use a Trane coil with your Trane system for optimum reliability.

Furnace
– Trane furnaces are uniquely designed to provide maximum heat with minimum fuel usage. And they think for themselves. Key furnace control functions are integrated into one microelectronic system that monitors the thermostat and gas valve, ensuring precise temperature control.

Air Cleaner
– An integral part of a home comfort system, filtering dust and pollutants out of the air you breathe, and keeping your rugs and home furnishings cleaner as well. Reduced pollen, dust, pet dander, smoke, etc., could help reduce allergy and asthma discomfort. A Trane CleanEffects™ air filtration system is up to 99.98% effective.

Humidifier
– By providing the right amount of moisture and preventing dry air conditions, a humidifier can help alleviate allergy symptoms and dry skin, and also reduce static electricity.

Thermostat
– The control center for your home comfort system. Trane’s digital, programmable thermostats give you precise temperature control and allow you to program your heating and cooling requirements depending upon your daily activities and schedule.

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Heat Pumps

The heat pump is effective in many geographies, but especially in the southern United States.

In all electric applications, the heat pump may consume less energy than an electric furnace or air handler with an added electric heater accessory. Why? Because it can deliver the same amount of BTUs as electric heaters using less electrical input. In moderate climates the savings that natural gas yields may not be as advantageous as in colder climates, since there is less frequent use of the furnace in milder climates. Of course, the heat pump can be matched with a gas furnace where preferred. The heat pump is effective by itself down to temperatures around 25 to 30 degrees Fahrenheit. At that point, either a gas furnace or an air handler with supplemental electric heat will kick in and help heat your home.

To determine which system would serve your specific needs best, your local Trane Comfort Specialist should perform a load calculation on your home and then estimate the cost of operation for the different combinations of equipment.

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Humidifiers

A humidifier adds water vapor to the air to increase humidity.

A humidifier is a machine that can be added to any central heating and cooling system to monitor the humidity levels in a home and increase humidity when needed.

HOW IT WORKS
The humidifier unit uses a humidity-sensing control that cycles the humidifier on and off and a water panel that adds water vapor to the circulated air when needed. Relative humidity is the amount of moisture in the air expressed as a percentage of the maximum amount that the air is capable of holding at a specific temperature. In dry air conditions, the sensor tracks that percentage and adjusts the amount of added water vapor, giving your skin the moisture it needs and helping to keep any personal belongings, such as wood floors, furnishings, and keepsakes, from drying out. In essence, it’s one more way Trane makes your home more comfortable all year long.

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Sizing Systems

It’s important to install the right Trane matched system size for your home, depending on a number of factors.

When it comes to your heating and air conditioning system, bigger isn’t always better, and smaller isn’t always more economical.

THE WRONG SYSTEM SIZE COULD COST YOU
A system that is too large will cool or heat your house quickly, but you still may not feel comfortable. That’s because it will satisfy the temperature setting on your thermostat before it can adequately remove sufficient moisture from the air – which is what makes you feel so sticky and uncomfortable in summer. What’s more, the stress of short cycling (too many starts and stops) will shorten the life of your equipment and increase your heating and air conditioning bills.

The wrong system will run constantly in the summer and the furnace will do the same in winter, which may overtax your system and increase your energy consumption.

CONSULT YOUR TRANE COMFORT SPECIALIST
In most homes across the country, systems are in fact too large. And an oversized system not only makes it more difficult to control your comfort levels, it costs you money, because you’re essentially paying to heat or cool space that isn’t even there. That’s why a properly completed load calculation is so important. Your independent Trane dealer can determine the correct system type and size for your home by doing a room-by-room load calculation. This heat loss/heat gain analysis is the best indicator of the correct system size and takes into consideration such critical factors as:

  • Climate
  • Number of windows and type of window treatments
  • Insulation and ductwork
  • Building materials and roof construction
  • Skylights and fireplaces
  • Ceiling heights
  • The number of people in your home

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