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HVAC Systems: How Your Heating & Cooling In Your House Works

HVAC Systems: How Your Heating & Cooling In Your House Works

HVAC typically refers to the heating and cooling system installed in a building – domestic or industrial. The acronym stands for Heating, Ventilation, and Cooling system. They are an essential part of any building. Apart from the thermal control and comfort they provide, they also contribute to the sustainability of any building project.

Knowledge of how HVACs work is essential for any building owner or tenant, primarily because of the power costs. A report from the U.S Small Business Administration showed that HVAC systems typically account for around 40% of the energy consumption in a commercial building. In domestic buildings, the consumption percentage drops to approximately 17%. The result of this is that building owners are consistently looking for ways to optimize their HVACs for energy consumption.

Types of HVACs

While the name HVAC can give the impression of large and complex systems, they are very common. The classifications of HVAC systems depend on the usage of the system. There are four broad categories:

  • Single Stage HVAC System: These systems are frequently used by people living in hot or cold climates. They are designed to either cool or heat an area. They are typically inexpensive and are inefficient due to a lack of sophistication. An example of a single-stage HVAC is an air conditioner unit.
  • Advanced Single Stage HVAC System: Similar to the regular single-stage units, this class of HVACs offers variable fan speeds to reduce energy consumption. However, they remain inefficient due to a lack of programmability.
  • Zoned HVAC System: Owners of large properties typically use these systems. They are used to heat or cool individual parts of the building. They are usually designed using zone valves and dampers fixed inside the vents and ducts, which selectively block the airflow.
  • Humidity Control HVAC System: For people who live in the tropics or dry regions, having humidity control is important. This is why they are more likely to go for HVAC units that have both humidifiers and dehumidifiers. Some people, though, may prefer having separate units for managing humidity. This is necessary if you don’t want to have to turn on the cooling or heating system while trying to regulate your HVAC.

Parts of an HVAC System

In most homes, HVAC systems are composed of multiple consolidated units that contribute to improving indoor air quality and comfort. Here are the most common parts of an HVAC system:

  • Furnace: Typically located in the basement, this is one of the most critical parts of the system. Its principal function is to transfer air from the heat exchanger into the air ducts. It’s usually the biggest part of any HVAC unit.
  • Heat Exchanger: These are typically located inside the furnace and work to add heat to air from the combustion chamber.  
  • Evaporator Coil: Also found in the furnace, this component contains a refrigerant so that it absorbs heat from the surrounding air. Once the air has been cooled, it’s then passed through air ducts all over the home.
  • Condensing Unit: This unit does the reverse of what the evaporating coil does – give off heat to the air. It’s usually used in outdoor HVAC units.
  • Refrigerant Tubes: Metal tubes that connect the evaporator coil with the condensing unit. The tubes also contain cooling refrigerant.
  • Thermostat: Probably the most popular part of an HVAC system, this unit is used to maintain the required temperature within a room. Depending on what temperature you set the thermostat to, it will alternate between putting on the air conditioning or heating system.
  • Ductwork: This consists of all the air ducts or pipes moving air throughout your home. The ductwork design is crucial because it controls the distribution of air around your home.
  • Vents: These rectangular-shaped covers on the floors, walls or ceiling, deliver and take air into, and out of, the room.
  • Heat Pump: Their primary function is to move heat inside and outside the house. In warm months, they take the heat outside the house; in cold months, they do the opposite.

The interconnection of the units in this system means that they rely on one another to function effectively. If one unit has an issue, it will affect the others.

Making HVACs Energy-Efficient

As mentioned earlier, HVACs constitute a significant contributor to high energy usage in most buildings. Therefore, optimizing them for energy consumption can provide substantial relief in terms of cost. In addition to reducing costs, bringing down energy consumption is a significant step in achieving environmental sustainability.

 Here are a couple of ways you can improve your HVAC systems:

  • Design: One mistake rookie property owners make is not considering the nature of their HVAC system when planning the architecture of their building. Apart from the technical nightmare that this rookie mistake can cause, it also results in energy code violations with the Department of Energy.  

HVAC systems are intricately linked with the design of a building. It can either accentuate its effects or diminish them. Most modern home designs allow for more natural temperature control methods to reduce the workload on the heating and cooling systems.

It’s also essential to use a properly sized system with allowance for changes. You should make sure modular equipment is used, so that if there’s a need for expansion in the future, it will be hitch-free.

  • Maintenance: Because most of the HVAC system is hidden away, it’s quite natural for you to forget that they need to be maintained. Poorly maintained HVACs would be inefficient and consume even more power than normal. Carrying out maintenance bi-annually, at least, is vital to keep the system functioning. Always make sure the repair is carried out by licensed personnel, as any attempt to do it yourself may result in even worse problems. Some of the more common maintenance tasks should include:
      • Replacing air filters
      • Inspecting air ducts and pipes for leakages and damages
      • Cleaning heat transfer coils in heat pumps and air conditioners
      • Inspecting the furnace
      • Fixing air ducts and fan motors
  • Use a programmable thermostat: Achieving efficiency with your HVAC requires being conscious of subtle temperature changes. Being able to program the thermostat settings ahead of time is a considerable advantage, as human errors and oversight can prove very costly.  

You should program the thermostat for higher temperatures during the summer and lower setpoints in the winter. You should also make sure to turn off the system when the building isn’t in use. Some thermostats can be programmed to only switch on air when a room is occupied.  

Caution should be taken when positioning the thermostat, though. It should be placed in a location where the temperature is an adequate representation of the room. This means it shouldn’t be placed anywhere near an air conditioning unit, heat vent, or heat-generating electronic equipment.

  • Use an Energy Management System (EMS): Also known as Building Energy Management Systems (BEMS), they are computer controls that regulate the HVAC in a building alongside other energy systems. These systems also provide notifications and alarms when the HVAC stops operating efficiently. They are more common in large, complex structures, but there are smaller ones that do the same job for a small building.  

The management system is usually programmable to adjust indoor air temperatures based on the temperature and humidity to allow HVACs to operate efficiently. They can also be used to prevent over-cooling or over-heating of spaces within the house.

Apart from managing internal temperature, EMS systems are also useful for regulating lighting, fire suppression, and security. The systems typically produce intelligent reports on problems and recommendations with a building’s energy consumption system. You can use them to manage your entire energy load. They have been observed to save as much as 50% of energy costs when properly installed.

  • Upgrade Your HVAC System: Over time, it’s normal for wear and tear set in on your HVAC, and you’ll have to change it. Sticking with a faulty HVAC can result in significant energy losses. Scheduling a replacement will typically cost less than if you wait for a breakdown in the system before getting an emergency replacement. 

However, the units are typically cost-intensive. Unless you have significant energy losses and the system is close to the end of its life, you may not need to replace it. If you have made alterations to any heating or cooling equipment, you may also need to change some components of your HVAC unit.

HVAC Emergencies

If you encounter any HVAC emergency, hire professional to handle the job.

Not all HVAC problems are equal and many homeowners are unsure when an HVAC problem warrants calling hiring emergency HVAC services. Check this guideline to help you assess your HVAC situation.

  • Air Conditioner Failure

When your HVAC unit stops cooling, the interior temperature can soar rapidly. If your AC fails, it’s considered an HVAC emergency, especially if you have elderly family members, young children, or pets at home.

  • No Heat

You need adequate heating when the temperatures fall below freezing. If your furnace or pump isn’t producing heat, that warrants seeking an emergency HVAC technician.

  • Safety Concerns

HVAC system related issues that are serious safety concerns include leaking gas or refrigerant, smoke, and sparks. Don’t wait and see what happens. Call an HVAC repair technician immediately. Never compromise the safety of your family and home because of such HVAC problems.

Choosing HVAC Services

When you need to hire an HVAC repair technician, it is important to take some things into consideration. You want to ensure that you’ll be working with a qualified HVAC professional and get the most out of the cost of seeking HVAC services. 

Here are some tips when hiring HVAC services:

  • Check insurance and bond to ensure that the HVAC company won’t be obliging you to pay out of your pocket if any of their workers got injured while repairing your HVAC system.
  • Check the credentials of the HVAC professional and ask about the work experience to avoid compromising quality of work.
  • Get an estimate quote of the total HVAC service cost. It will avoid surprises in the billing after the project is finished.
  • Check reviews and ask referrals from family and friends to help you search for the best HVAC company near you. 


Whether you’re building, buying, or renting a home, having a good knowledge of HVACs is imperative. Having energy-efficient HVAC systems is a benefit to everyone. It improves the quality of air and overall comfort while bringing down energy cost, consumption, and greenhouse gas emissions. Always keep in mind that small fixes like air conditioner repair, changing air filters, and sealing up leakages in air ducts and vents go a long way to both improve the lifespan of the system and maintain efficiency.