HVAC Systems

HVAC Systems

HVAC Systems are first delineated by their application. This usually falls into one of 3 areas:

  • Residential
  • Commercial
  • Industrial

The dividing line between commercial and industrial HVAC solutions can sometimes be unclear. The difference is typically a matter of scale and special use.

Residential HVAC Systems

Residential HVAC is, as it sounds, the air conditioning equipment that heats and cools your home. It also includes equipment that work in tandem with your HVAC equipment to control indoor air quality. Residential HVAC equipment typically has a heating capacity between 50,000 and 150,000 BTU/hr and a cooling capacity of 5 Tons or less. When homes exceed these capacities, multiple HVAC systems are employed to meet the air conditioning needs.

Several things must be considered when planning an air conditioning installation at your home. These are the larger contributors to making these decisions.

  • Home construction and design
  • Personal preference
  • Geographic location

Home construction and design

Choosing the proper sized HVAC equipment

The most important factor is selecting the capacity needed. This is accomplished by performing a Manual J Load Calculation. There are many variables that enter this calculation. The chief variable is typically a matter of square footage. Larger homes need more cooling capacity. Energy efficient homes must also consider insulation type, windows, doors, ceilings, etc.

An under or oversized air conditioner can cause problems for the comfort in your home. An undersized HVAC unit will not meet the heating and colling demands of your home. It will run longer running up high utility bills. An oversized air conditioner can also be a problem. While removing the heat from your air, the humidity condenses on the cooling coils and the water drains from your home. In order to do this effectively, your air conditioner must run for a bit of time. An oversized air conditioning unit will run for less time removing less moisture from the air. High humidity will cause you to change the thermostat to a lower temperature to achieve a comfortable temperature. High humidity can also cause indoor air quality problems.

HVAC System configuration

The design of your home impact what equipment configuration will be needed to best serve your heating and air conditioning needs. You can read more about it in our article, Split or package?

Split heat pump condenser

Packaged air conditioner and gas furnace

Personal Preference

Homeowners have to make decisions about efficiency, interface, and comfort. This is typically a matter of budget. Residential HVAC equipment energy efficiency varies between 14 and 20 SEER. Interface is typically about the thermostat and it’s capability. Comfort varies person to person. Your HVAC system may need to be zoned to achieve the best results in personal comfort. You can read more about zoning in our article, Modern HVAC.

HVAC Efficiency

Air conditioners and heat pumps start at a minimum energy efficiency of 14 SEER. In general, ducted systems top out at 20 SEER. 16 SEER is the top selling ducted HVAC system. Ductless heat pumps can get up to 26 SEER in efficiency. Several things come into play when deciding which efficiency to choose. Homeowners that want the most energy efficient home possible may choose 20 SEER. With the increase in SEER, there is an increase in price. A 20 SEER system is 2.5 times more expensive than a 14 SEER. As efficiency goes up so does the technology. 18 SEER variable speed systems are typically communicating systems.

HVAC Interface

Homeowners can choose among many thermostat brands and features. Some of these are described in our article, Modern HVAC.


Comfort options start with simple things like the edition of an extra return in a bedroom or master suite to improve air exchange. They can quickly escalate to other HVAC solutions like zoning or mini-splits. The HVAC industry is changing quickly to higher levels of technology. As entertainment has become increasingly individual, HVAC companies are seeking to go beyond "home" comfort by providing individual comfort.

Indoor air quality

The COVID pandemic has shed new light on HVAC solutions to indoor air quality. These solutions vary by means and manufacturers. They can be installed or portable. High efficiency air cleaners installed in your HVAC system can be a whole home approach to reducing airborne pollutants. Portable units can be used in family rooms or bedrooms. Systems now incorporate ionization and UV lights to further sterilize indoor air.

The most effective but least common means of improving indoor air is natural ventilation. This has typically been accomplished by opening doors and windows. Year round ventilation is possible using an energy recovery ventilator (ERV) with your installed HVAC system. The ERV will exchange indoor and outdoor air, cooling the indoor air as it is induced and distributed using your installed ductwork. This is an investment that is recouped over time by money saved not purchasing replacement UV lights and high efficiency filter media.

high efficiency air filters

Energy Recovery Ventilation

Geographic Location

Where your home is built could limit the HVAC solutions available to you. Heating systems are most affected by geographic location. The availability and expense of natural gas or propane could necessitate using a heat pump. A colder climate could mean straight air conditioning rather than heat pump. Heat pumps are an inefficient heating system in colder climates.

However some locations open up other HVAC opportunities. The availability of a water source allows for the potential to install a water source heat pump. Traditional heat pumps exchange the heat to the surrounding air. Water source heat pumps are cooled by water. Typically, the water is either supplied from a deep well or is recirculated in a ground loop. There are many variations of ground loops, such as:

  • Open
  • Horizontal
  • Vertical
  • Slinky
  • Lake

Open loops draw water from a well and deposit the water in another well or in a nearby surface water. Ground loop systems recirculate the water through a long series of piping buried in the ground. Geothermal HVAC units are high efficiency units. They are also used in large high-end apartment buildings where a centralized water circulating system is installed.

Water source heat pump

Question: What is a communicating HVAC system?

Communicating controls are used in a wide range of HVAC applications, including ductless mini-splits, multi-stage air conditioners and heat pumps, multi-stage furnaces, multi-stage split system air conditioners and heat pumps, water source heat pumps, and zone control systems. Any HVAC application that uses multistage or modulating technology can benefit from communicating controls. Communicating controls can send commands and information over the same network, allowing complex control with just a few wires. Communication makes monitoring and controlling variable-capacity HVAC units much easier. The components send over information about their status and operating condition to the controller giving the controller real-time information on system operation. The HVAC system can then adjust to the information provided giving the homeowner the best possible solution to comfort and energy efficiency. A communicating system also provides fault codes and historical information that assist in HVAC repair.

HVAC Communicating Thermostat

Up next about HVAC

With the world HVAC changing so quickly and with so many technological advancements, the question is who will fix this stuff. In our next article, we'll take a look at HVAC Jobs and Careers.

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