Is the unit quiet during operation?

Most new HVAC units run quietly so they don't disturb people who are inside the building. Some window unit air conditioners and space heaters are noisier. It's best if you can see a demonstration of a unit before purchasing to determine how quiet or loud it is.

Sealed combustion chambers: Heaters and furnaces either have an open or sealed combustion chamber where the actual burners are located. Sealing the combustion chambers reduces noise coming from the furnace, so if you’re looking for a quiet furnace, be sure the combustion chambers are sealed.

Heaters and furnaces either have an open or sealed combustion chamber where the actual burners are located. Sealing the combustion chambers reduces noise coming from the furnace, so if you’re looking for a quiet furnace, be sure the combustion chambers are sealed. Compressor sound blankets: Sound blankets insulate an HVAC system or air conditioner by absorbing sound waves. Many units come with sound blankets, and they can also be added to noisy units to deaden the noise created by air conditioner compressors.

Sound blankets insulate an HVAC system or air conditioner by absorbing sound waves. Many units come with sound blankets, and they can also be added to noisy units to deaden the noise created by air conditioner compressors. Outdoor units placed far from windows: Installing the compressor and other outdoor parts far from windows reduces noise that can disturb building occupants. Talk to your installer about your options.

Is the unit energy efficient?

Energy efficiency refers to whether a unit’s output makes good, efficient use of the electricity or other power source it needs to operate. Both federal guidelines and individual design help HVAC units, air conditioners and heaters save energy.

High energy efficiency ratio: Heating and air conditioning units are required to include information on their Energy Efficiency Ratio (EER). This is a ratio of the systems output (measured in British thermal units, or BTUs) to the energy input it needs to operate (measured in watts). This ratio tells you how efficiently the system uses energy; the higher the number, the more efficient the unit.

Heating and air conditioning units are required to include information on their Energy Efficiency Ratio (EER). This is a ratio of the systems output (measured in British thermal units, or BTUs) to the energy input it needs to operate (measured in watts). This ratio tells you how efficiently the system uses energy; the higher the number, the more efficient the unit. Built to federal standards: Since air conditioners are one of the worst environmental offenders, federal guidelines in the United States require air conditioners to have an efficiency rating of at least 13-SEER. This means they provide a specific amount of air conditioning for each unit of energy used. For a more efficient and cost-effective machine, look for an even higher SEER rating.

Since air conditioners are one of the worst environmental offenders, federal guidelines in the United States require air conditioners to have an efficiency rating of at least 13-SEER. This means they provide a specific amount of air conditioning for each unit of energy used. For a more efficient and cost-effective machine, look for an even higher SEER rating. Financial savings: Not only will having an efficient machine use less energy and meet federal and local guidelines, but energy efficiency also means cost savings to you. The energy savings generally translate into lower electricity bills, plus some states offer tax rebates for people who purchase new energy efficient systems and household appliances.

Does the unit hold a constant temperature?

HVAC units, air conditioners and heaters help keep indoor temperatures stable and consistent so users feel more comfortable. But some units can hold a consistent temperature, while others create fluctuating temperatures in your home or office.

Heating and cooling capacity: Most HVAC units are designed to keep rooms at constant temperatures for optimal comfort. However, even if it is brand new and working properly, whether or not an HVAC system, heater or air conditioner can actually maintain that temperature depends on the temperature and humidity in your region. In very hot regions, you will need an HVAC or air conditioner with a high tonnage (a measure of air conditioning capacity). Space heaters and other types of room heaters may also be less effective in severely cold regions, and you may need to purchase more than one per room. Be careful to never plug more than one heater into the same outlet, which can overload the outlet and cause a fire.

Most HVAC units are designed to keep rooms at constant temperatures for optimal comfort. However, even if it is brand new and working properly, whether or not an HVAC system, heater or air conditioner can actually maintain that temperature depends on the temperature and humidity in your region. In very hot regions, you will need an HVAC or air conditioner with a high tonnage (a measure of air conditioning capacity). Space heaters and other types of room heaters may also be less effective in severely cold regions, and you may need to purchase more than one per room. Be careful to never plug more than one heater into the same outlet, which can overload the outlet and cause a fire. Adjustable ducts: Most HVAC systems allow users to adjust ducts to control temperature in different rooms. This means you can keep bedrooms or living areas cooler than less frequently used rooms, conserving energy and saving money on your electric bill.

Most HVAC systems allow users to adjust ducts to control temperature in different rooms. This means you can keep bedrooms or living areas cooler than less frequently used rooms, conserving energy and saving money on your electric bill. Return air diffusion: Some HVAC systems are set up so as much air is circulated into the room as is circulated out, thus keeping temperature constant and air clean. Air circulation increases the ability of the unit to hold steady temperatures throughout your home or building.

Is the equipment compliant with safety standards?

There are a lot of health and environmental risks associated with the chemicals and equipment in heating and cooling systems. Federal and state governments issue safety standards to ensure that heating and cooling equipment works correctly and safely.

Environmental safety standards: HVAC units, air conditioners and heaters must comply with environmental codes for energy efficiency, clean air and more. It can be hard to know if a given unit meets these standards, but generally major manufacturers in the United States all meet these standards (or else they would not be able to pass inspections and market their products). To be sure, you can look for the Energy Star certification on any heating or air conditioning equipment (as well as many other home appliances), which indicates that the unit has met or exceeded efficiency standards.

HVAC units, air conditioners and heaters must comply with environmental codes for energy efficiency, clean air and more. It can be hard to know if a given unit meets these standards, but generally major manufacturers in the United States all meet these standards (or else they would not be able to pass inspections and market their products). To be sure, you can look for the Energy Star certification on any heating or air conditioning equipment (as well as many other home appliances), which indicates that the unit has met or exceeded efficiency standards. Environmentally-friendly refrigerants: Air conditioners can be dangerous to the environment because of the chemicals in their refrigerants. Previously, most units used a refrigerant called R-22, but most manufacturers are phasing out production of these units because this chemical can be dangerous. Instead, look for a unit that uses R-410A, which is chlorine-free and safer for your family and the environment.

Air conditioners can be dangerous to the environment because of the chemicals in their refrigerants. Previously, most units used a refrigerant called R-22, but most manufacturers are phasing out production of these units because this chemical can be dangerous. Instead, look for a unit that uses R-410A, which is chlorine-free and safer for your family and the environment. Ventilation standards: HVAC units must provide appropriate ventilation to lower the risk of respiratory infections and complications. The American Society of Heating and Air-Conditioning Engineers (ASHAE) sets the standards for ventilation, which are updated every few years; check to see that your installer is ASHAE-certified, which indicates that they follow the guidelines set by ASHAE.

Is the unit indoors or outdoors?

While heaters and furnaces are usually located inside, HVAC systems and air conditioners can contain both an indoor and outdoor unit for compressing and circulating air appropriately. If you have no outdoor space or prefer an indoor-only unit, your options will be more limited.

Outdoor compression units: Many HVAC units come with an outdoor compressor that can be placed at a distance from the building to eliminate noise and improve air quality. This helps to ensure fresh air flow to the dwelling or building.

Many HVAC units come with an outdoor compressor that can be placed at a distance from the building to eliminate noise and improve air quality. This helps to ensure fresh air flow to the dwelling or building. Ducts and vents: Complete HVAC systems typically feature an entire system of ducts throughout a home’s attic or basement area. These ducts connect to vents in every room, allowing warm and cool air to circulate in and out. If your home or building is not equipped with a ventilation system, you can have one installed, but the process is expensive. If you can’t afford or don’t want to install a ventilation system, you will need to rely on window air conditioning units, fans, space heaters and other similar solutions.

Complete HVAC systems typically feature an entire system of ducts throughout a home’s attic or basement area. These ducts connect to vents in every room, allowing warm and cool air to circulate in and out. If your home or building is not equipped with a ventilation system, you can have one installed, but the process is expensive. If you can’t afford or don’t want to install a ventilation system, you will need to rely on window air conditioning units, fans, space heaters and other similar solutions. Furnace location: Many homes in cold regions or areas that experience a cold winter and that do not have a HVAC system often have a furnace instead, which is connected to a duct system to warm the home. Furnaces can be located in any indoor closet but generally should be inaccessible to pets and children, especially if the heating elements are exposed. Many people opt to put the furnace in the garage area. If there is no closet in your garage to house the furnace, consider having one built.

Who will work on the units?

Depending on what type of HVAC or individual heating and cooling units you have installed in your home, you may need to work with various specialists. Be sure there are installers or service people available in your area.