Top 50 Interview Questions with Answers on HVAC system

When you face an interview, you might be anxious about very different things apart from the topic like thinking of failure in the interview which would give you a nightmare chill during the interview.

So when you are applying for an HVAC technician job, prepare yourself for the interview as much as possible. No matter whether you have prior experience as an HVAC technician, you are likely to be asked various questions requiring knowledge of the HVAC industry.

Top 50 Interview Questions for HVAC system

As you prepare for the HVAC interview process, we will provide you with a list of questions that you may be asked during the interview process and will help you to anticipate what the interviewer will ask.

1. What is the full abbreviation of the term HVAC?

Heating, ventilation, and air conditioning is the full name of HVAC systems.

2. What are the workings of the HVAC System?

HVAC systems are designed to regulate the environmental conditions in which they operate.

In order to achieve this, a room’s temperature is controlled through heating and cooling. In addition to controlling the humidity in the environment, it also controls how the air moves and is distributed inside.

Due to the presence of the HVAC System there is a guarantee of the purity and cleanliness of the air in the given environment where this system is employed.

3. Why you as an employee are interested in this role?

In this question, you must answer the reason for which you have come to apply for the particular job role. You must truly be passionate about your job role and the answer must come out as honest, natural, convincing and genuine. To get an idea you must give your answer something like this:

Having the opportunity to work with specialists who are knowledgeable and skilled is very exciting to me. In addition to installing and repairing HVAC equipment, I can also help others with their unique needs. It makes me feel good to assist people with their comfort in both cold and hot weather. Also, this job will allow me to have proper interaction directly with every customer and understand their problems one-on-one and get to solve their problems, make more positive impacts in their lives and also have the ability to learn more as I am aware of the fact that acute temperatures can affect people and can make their health deteriorate so I am dedicated to helping them get over such problems”.

4. What are the requirements of an HVAC System?

There are multiple types of HVAC Systems and each system will have different various requirements. It is very crucial to first research about the design codes and other energy standards which are dependent on the fact of the location of the system.

5. What is actually the role of an HVAC System engineer?

This question is asked to you by the interviewer so that the interviewer gets to know whether you are aware of the responsibilities and role of an HVAC technician and are aware of all the duties when you are being hired for the job.

As you align the responsibilities of an HVAC system engineer with the job, you should list a few of their responsibilities. You must answer this particular question in somewhat the following manner

“A HVAC System engineer has to perform a through checkup of the HVAC system to see which part is damage & repair it that part is in a warranty period.

In addition to removing and installing old HVAC systems, HVAC technicians also conduct routine maintenance, train other members, meet local HVAC codes, and order and maintain equipment.”

6. Is it necessary for an HVAC technician to possess certain qualities to succeed? If so what are those qualities?

It is extremely important and a necessity for an HVAC technician to possess all necessary qualities and skills in order to not only work efficiently but also to be able to serve the customers with more knowledge, confidence and accuracy.

This question is intended to determine if you know the characteristics you should have as an HVAC technician. Give some examples of the qualities an HVAC technician exhibits in your response while connecting them to the employer’s needs.

You can give your answers by saying something like

To be successful as an HVAC technician, time-management, organizational, troubleshooting, communication, and critical thinking skills are essential. The technician must also be flexible and willing to learn. A mechanically inclined individual also needs to comprehend components, testers, systems, and tools. HVAC technicians must also be patient, pay attention to details, and be creative as well as customer service oriented.”

7. How can you increase the efficiency and longevity of a HVAC System?

The best process to enhance a particular HVAC System’s rendition is to clean and change the air filters on a regular basis. Some of these methods are purchasing a programmable thermostat, drawing curtains or installing shades in rooms exposed to sunlight, and not blocking airflow by closing multiple vents in multiple rooms.

8. Can you convey your daily routine as an HVAC Technician?

Interviewers might ask you this question to determine how you will prioritize your daily tasks and how you will work as a professional throughout the day. Make sure that your response highlights your ability to manage your time effectively.

For example, you can say something like

“Firstly I review all my important mails and phone calls and then shortlisted the crucial job that needs more attention based on their importance. Afterwards, I perform routine duties, including the removal of old air conditioning systems, the installation of new systems, performing routine maintenance, training other members, complying with local HVAC codes, and updating equipment.”

9. How Do You Approach This Role With The Right Strategies And Mindset?

To determine your aptitude for the role, the interviewer will ask you about your mindset. Briefly describe what strategies you will use and how you will approach the role.

Examples might include the following:

“HVAC technicians should understand the responsibilities closely.  A technician should be knowledgeable of the safety hazards involved with repairing heating, ventilation, and cooling systems. In order to provide quality HVAC services, HVAC technicians need to have a clear mindset, which includes understanding how to prevent accidents and inspect and solve potential problems.”

10. What do you think could be the biggest challenge that you think you are going to face in this particular job?

Interviewers will ask you if you are aware of the developments that have occurred in this field. You should discuss the challenges you expect to encounter in this position.

As an answer, you can say something like

“Although I believe that I am capable of facing any upcoming challenge to deliver my full potential. But there might be some issues if there is a lot of work in hand at one particular time. If I have someone to assist me or someone to help me from my team then it would be easy for me to perform all the tasks efficiently.  I might find any task challenging, I am eager to t to do it skillfully.”

11. How do you plan to keep yourself motivated during work?

Providing an answer to this question helps the interviewer get a better sense of your interests and values. As you relate your work to your professional values, share what you value professionally

You can answer in this manner,

“It motivates me to offer solutions to people. The joy I get when I bring a smile to someone’s face motivates me. My goal in life is to make this world a better place to live by utilizing my skills. The fact that I want to become better and improve also motivates me to pursue bigger challenges.”

12. Where can I find information on choosing an HVAC filter?

It is always a good idea to start by looking at the size of the filter your system is designed for. Take the minimum efficiency reporting value (MERV) into account for each filter. reporting value (MERV). Homeowners who suffer from asthma or allergies typically need a higher-grade filter. Nevertheless, pleated air filters are effective in reducing allergens, but overusing them can cause them to clog.

13. What size of filter does a person need?

It is not an easy question to answer. What size heating and cooling system you need will depend on a number of factors. You may be required to purchase a different size unit depending on your house’s walls, insulation, attic space, and more. Oversized systems can make a house too humid, which could lead to mould and moisture issues. Having a small system will increase your energy bills since it runs constantly. The size of the air conditioner you need for your house should be determined by a professional.

14. What self-maintenance can a person do in an AC?

Keep your air filters changed regularly, and clean the outside coils once a month when the cold season arrives. We as HVAC technicians should educate customers and other people on the right process for the self-maintenance of an AC, because of which not only the Air Conditioner will perform better but also save the customer some amount of money.

Basic maintenance such as keeping the filter clean, and cleaning the coils and fins of the Air conditioner will help the Air conditioner to be clean and work efficiently.

15. Can you define CAV?

Heating, ventilating, and air conditioning (HVAC) systems with constant air volume are termed Constant Air Volume (CAV) systems. When a space is heated or cooled, the supply air temperature is adjusted based on the thermal load. The temperature of the supply air varies with the flow rate of supply air in a simple CAV system. The majority of CAV systems serve a single thermal zone.

16. What is it about you that makes you the best fit for this position?

Recruiters are looking to see if your qualifications match the company’s needs. Here is your chance to display your skills, abilities, traits, experiences, education, and achievements. You can answer with something like

“My degree is a bachelor’s in mechanical engineering. I am a licensed HVAC technician. In addition, I am a self-driven communicator with strong organizational and communication skills. My HVAC skills have also been developed. My previous experience includes working as a heating, air conditioning, and refrigeration technician where I installed, maintained, and repaired these systems.”

17. How does VAV work? What is your understanding of it?

“VAV” refers to pressure-dependent and pressure-independent systems. These systems are designed to control temperature and airflow. When using the Pressure dependent method, the terminal unit provides air depending on the static pressure (SP) in the air duct. Flow-sensing devices in pressure-independent terminal units limit the flow rate through the unit. They are independent of the SP in the primary air duct since they can control the maximum and minimum CFM. The airflow from each terminal will be optimal if pressure-independent systems are balanced.

18. You are approached by a client who is concerned about energy costs. What would be the best way to approach that client?

Employers can learn if you have solid customer service skills by how you answer this question. Providing an answer that includes both parts of the question is the best way to answer this question. A good example would be:

My approach to the client will depend on the energy concern they raise. I might recommend a retrofitting of his existing unit if he wants better energy but does not want a new one. It will save the client money while improving the efficiency of the existing unit.”

19. Elucidate the various types of air-conditioning systems.

To gauge your knowledge of this field, your interviewer asks you this question. Demonstrate your expertise by describing the conditioning systems you might have worked with. Say something like

Air Conditioners are of various types which are available throughout the global market. Some exclusive varieties of Air Conditioners include, Central and Window Models, Compact Air Conditioners, and Split Air Conditioners etc. You can also go through other varieties of Air Conditioners based on your household preferences.

20. Are you familiar with using technology to explain options to your customers?

An employer wants to know whether you have experience using a variety of technologies in this field. Please provide an example of your experience using technology at work in response to this question

“Certainly, I have. In the past, I used HVAC software that I was able to easily manage through my phone. The app allows me to show clients digital prices for books, provide them with options for invoices, and accept payments. My clients and I were able to work more efficiently this way. We provided clients with a wide range of options before we began any work.”

21. What Are Your Methods For Staying Up-To-Date With HVAC Developments?

The interviewer can determine your knowledge of HVAC developments by your answer to this question. You have to answer this by saying, “I am familiar with the development of HVAC.”

“We have instructors here who keep the HVAC technicians up to date on the latest trends. I also share the latest developments with other HVAC professionals through a cordial relationship.”

22. Has there ever been a conflict between you and the boss of your previous company? If so, how did it resolve itself?

Conflict management is one of the questions the interviewer will ask. This is because they realize that many employees have problems with conflict management. In answering this question, it is best to briefly describe the conflict and focus on its resolution.

As far as I can recall, I haven’t had any conflict with my boss. However, if one arises during my workday, I would set up a meeting with my boss so we can discuss the conflict. Whenever I make a mistake, I apologize and admit my mistakes. Communication skills, respect, and strong interpersonal skills can help resolve disagreements.”

23. Can you explain how the Vapour Compression Cycle Works?

Compressors compress refrigerants, as their name implies. Gas from the evaporator is supplied to the compressor, which converts it into high-pressure gas. During the compression process, the temperature of the gas rises. As the hot refrigerant gases flow into the condenser, they are cooled.

24. When working as an HVAC technician, what have been the most challenging situations you have encountered and how did you handle them?

A strong interpersonal skill is required for HVAC technicians, according to interviewers. You can show how you would handle a challenging situation at work by answering this question.

“I will surely do anything within my limits to ensure that I deliver quick and smooth services, which will ensure the clients are satisfied with my performing works.  

Our fan was in the back in the truck so I lent it to them while we went to get the part, and they were grateful for the thoughtful gesture. Having received the part, we came back shortly after to give the customer a time frame before we could fix the unit.”

The client was calmed and felt heard and understood by empathizing with them and having open communication throughout the process.”

25. You have another appointment to attend and your customer’s job is taking longer than expected. How should you proceed?

HVAC technicians have an extremely engaging career, and there may be days when you’re required to do many tasks before your shift ends. It is important for the interviewer to see how you handle challenging situations, as some jobs may take longer than you originally anticipated.

“For any kind of inconveniences or any kind of problematic situations, such as arriving lately, or misunderstanding with our respective clients, I will surely try to solve the issues and make them right. Timely arrival is important to me.

Having transparency is a critical element to building rapport with customers, so I will do whatever it takes to ensure that they are satisfied at the end of the appointment.”

26. Can you tell me about the safety violations that you see most often, and what would you do to prevent them?

When it comes to HVAC, safety is imperative. It doesn’t matter whether the technician is working in a customer’s home or business, or whether he’s preventing an injury on the job. You can use the applicant’s answers to improve safety training procedures or remove unnecessary rules by assessing the applicant’s HVAC safety knowledge.

27. Is there a difference between a heat pump, heating, and refrigeration?

The movement of heat between locations is a requirement for heating and cooling. The energy from a source is transferred by means of a heat pump or a motor. They pump heat both inward and outward from the inside to the outside which will cause cooling and from the outside to the inside heating. The cooling effect of air conditioners and refrigerators actually reduces the amount of heat in a room.

28. What are your take on mobile technology and its role in the HVAC industry?

Increasingly, HVAC contractors use technology to boost efficiency and streamline business operations. A candidate’s response to this question indicates their knowledge of current HVAC technology and trends. The tech skills of a candidate can help the recruiter decide whether they are a good fit for your company if your business currently uses HVAC software.

29. Can you tell me about your experience on how you used or plan on implementing mobile technology on the job?

An interviewer asks this question to understand a candidate’s previous experience, as well as how comfortable they are using technology in the field. Furthermore, it provides a good indication of how much training the candidate needs. HVAC technicians typically use their mobile devices to communicate with dispatch, estimate work and collect payments.

30. Do you what is BTU?

 British Thermal Units are abbreviated as BTUs. An increase of one degree   Fahrenheit in the temperature of 1 pound of water requires this amount of energy. One kitchen match creates the same amount of heat as one BTU.

31. Describe what a SEER rating is.

Temperature-regulated air conditioners or heat pumps are measured by seasonal energy efficiency ratios to see how efficiently they work during the cooling season. Those with higher SEER ratings work more efficiently. In order to calculate the SEER rating, we divide the cooling output for a typical cooling season by the amount of electric energy produced during that same timeframe.

The higher the SEER rating means that the product is more energy-efficient. As a downside, homeowners may have to spend thousands of dollars more to purchase a higher SEER system, and it might take them ten years to recoup their initial investment. Ask your HVAC professional for advice on what system is best for the customer in regards to their home and budget.

32. How do you calculate a SEER ratio?

Over an entire cooling season, the SEER ratio is calculated using a constant indoor temperature and a variety of outdoor temperatures ranging from 60 degrees to 100 degrees.

33. What do you mean by AFUE rating?

The acronym for AFUE is Annual Fuel Utilization Efficiency. The rating is based on how much heat a furnace produces versus how much fuel it consumes. The AFUE rating of 93 is an indication that 93 per cent of the fuel consumed by the furnace will be converted into heat for your house while the remaining 7 per cent will be wasted in the vents.

34. What are the factors that are to be considered while selecting the correct HVAC System? Can you explain these factors to the customer?

This question is for the interviewer to see if you can make the customer understand the factors and doubts which are needed to be considered before installing an HVAC system. You need to tell and explain to the client these fooling factors.

In order to choose the most appropriate HVAC system, certain factors should be considered. The following factors should be considered and need to be explained to the customer:

  • How old and how big the house is.
  • You need to know how many rooms you want cooling
  • The local climate of the house
  • Costs are associated with utilities at the local and regional levels.
  • The list of the available warranties
  • The type of system that best meets the needs of the customer.

Heating, ventilating, and air conditioning systems ensure your home’s temperature and humidity in an efficient, environmentally friendly manner and thus it is your duty to make the customer understand every factor properly so they can get the best service and system best suited for them.

35.  Why is it important to maintain negative pressure certain areas?

Several isolation techniques are used in hospitals and medical centres to prevent cross-contamination between rooms, including negative room pressure. This system features a ventilation system that generates negative pressure in an isolation room to allow air to flow in but prevent it from escaping.

In order to isolate a negative pressure room we have to follow these steps:

  • Air changes should be at least 12 per hour.
  • Ideally, doors should automatically close
  • It is important to seal the room well
  • There should be about 30% more negative pressure than supply
  • It is recommended to have negative pressure in the bathroom
  • Exhaust from the isolation room should be at least 25 feet from other ventilation intakes
  • It is necessary to oversize the exhaust duct to allow for loss of efficiency.

36. How to calculate duct size?

A ductulator or software program can be used to calculate duct size. A ductulator will give you the sizes of the ducts based on the distance between the ducts.

VRM (Velocity Reduction Method) or Constant Velocity Method

FLM (Friction loss method) or EFM (Equal friction method)

To calculate the duct sizing we need two entities to use the Velocity Reduction Method (VRM).

The volume of the material (CFM: Cubic Feet per Minute)

Velocity (in feet per minute: FPM)

37. What are the kinds of compressors?

There are many kinds of compressors which are used for different use case scenarios

There are high capacity and high energy efficiency compressors like

  • Screw Compressor
  • Centrifugal Compressor
  • Scroll Compressor

There are low capacity and low energy efficiency like

  • Rotary Compressor
  • Reciprocating Compressor

38. Please describe the types of Condensers?

There are basically two types of condensers which are

  • Water-cooled Condenser
  • Air-cooled Condenser

39. Can you list the types of A/C filters?

There are many types of air condition filter that exists. Some of the main and well-known A/C filters are as follows:

  • Ulpa Filter
  • Hepa Filter
  • Microbe Fine Filter
  • Carbon Filter
  • Packet or Bag Filter
  • Micron Filter
  • Mini Pleat Filter

40. Do you know about the chiller? If so please define

Yes Sir/Madam I know about the chiller. The chiller works by producing chilled water that is then used to absorb heat in the room. HVAC systems are not complete without chillers. These devices control the heated water in HVAC systems.

41. What are common types of chillers in HVAC?

A central air conditioning system consists of five main types of chillers: centrifugal chillers, air-cooled chillers, hybrid chillers, magnetic bearing chillers, and heat recovery chillers.

Amongst these, the centrifugal chiller is the most common type of chiller in HVAC.

42. What do you know about relative humidity?

The relative humidity in the air measures the amount of moisture present in the air relative to the amount of moisture in saturated air.  Having a relative humidity of 100 per cent means that the air is simply saturated with water vapour and can not hold any more, creating the possibility of rain.

43. What are the various types of Air conditioners?

The most commonly used types of Air conditioners are

Direct Expansions to air conditioners are

  • PAC (Precision Air Conditioning)
  • Split Air conditioner
  • Windows Air conditioner

Indirect Expansions to air conditioners are

  • AHU (Air Handling Unit)
  • Chillers

44. How does a refrigerant compressor work?

Refrigerator coils are made up of condensed refrigerant vapour which is constrained by the compressor. It raises the pressure of the vapour, which is pushed into the coils.

Heat is generated from the coils when it comes into contact with the cooler kitchen air temperature.

Cooling occurs as a result of the refrigerant absorbing heat from within the refrigerator.

45. What other skills do mechanics need in addition to HVAC skills?

Inquire what the interviewer means by the term other skills. If he or she means that you need to show your communication and computer skills, then discuss them. Provide a general answer that mentions a few skills if it is unclear what they mean by other skills.

You can answer with something like.

As a mechanic, I should also have computer skills since you have to keep track of your customers and their vehicles using software like Word and Excel. Since many of them are working in customer service capacities, they also need to be good listeners and communicators. Mechanics often have to deal with frustrated or scared people, so they need empathy as well. Furthermore, because they may have to work on extremely small components in a very small space, they should be detail-oriented.

46. What qualities do you look for in an employee?

Your ability to answer this question will differentiate you from other candidates. It demonstrates to the interviewer that you value and recognize others’ qualities. It is a well-designed interview question. With this and your resume demonstrates that you’re interested both in the job and in the company.

Interviewer might say that they are looking for someone who is going to add some skill & talent to their team.  If they have the same values that I have, I will consider them. As a team player, I also look for someone who will do things on their own initiative. The people I like to hire are those who ask questions, who are curious, and who want to learn and grow in their career.”

47. When it comes to your job, what is most important to you?

Not just a job, HVAC is a career. If you want to be successful in your career, you must be honest with yourself about what success means to you and how your definition of success matches the type of job you want to do. Answers should demonstrate that you know what the responsibilities and obligations of the job are and that you have the knowledge, skills, and abilities needed to succeed.

“As part of this role, I intend to make the most effective use of my HVAC knowledge and expertise. Because I have a strong mathematical mind, I enjoy formulating how to ensure an installation gets the proper amount of air into a room. In addition to working with machinery, I enjoy doing other things as well. My favorite part of my job is finding and repairing HVAC issues.”

48. What experience do you have with residential heating and cooling systems?

When the interviewer asks this particular question, then you should showcase your HVAC system skills & codes that will give you a solid indication for domestic as well as commercial purposes.

By learning about the types of equipment you’d find in a home, you can learn about how temperature is controlled.

You can answer with something like this,

For quality air control for mortgage holders, I introduce and keep up ductless part framework units for HVAC system.

It is a very different experience to work on residential and commercial heating and cooling systems. Because older homes were not built with efficiency in mind, their ductwork and components tend to be problematic. It was very beneficial to receive all the training I received.”

49. What is the best thing that you think about having a job as an HVAC technician?

A sentence or two should suffice for your answer. Make sure you highlight your key strengths and why you enjoy working in your field. It is important that you demonstrate that you get along well with others during the interview. In addition, the interviewer wants to learn if you have any motivations outside of work that could affect your work ethic, such as your education or extra-curricular activities, as well as whether you align your motivations and ambitions with the business’s objectives.

For example,

“First and foremost, we need to solve all the problems, but I can be flexible when it comes to my schedule. My job gives me a lot of creative freedom where I can showcase my skills. A big part of my job is keeping people safe at home and saving them money on their utility bills. I am excited about opportunities for growth our company has and I look forward to pursuing them.”

50. Define HVAC System?

HVAC consists of three basic components which are heating, ventilation, and air conditioning. Residential and commercial buildings are heated and cooled by this system. The use of HVAC systems can be found in many places, from single-family homes to submarines. As new construction continues, these systems are becoming more popular as a means of keeping indoor air quality high by utilizing fresh air from outside.

Ventilation, also in HVAC, refers to the activity of replacing or exchanging air. In addition to removing moisture, smoke, odors, heat, dust, airborne bacteria, carbon dioxide, and other gases, this process also controls temperature and replenishes oxygen in the air.


The Interview process for an HVAC system engineer might be a little difficult, but if you have the proper knowledge, experience and confidence about the job that you are going to do then you can easily crack the job interview.

Interviewers and employers are primarily interested in employees with excellent communication skills, a polite demeanor, a positive outlook, good critical thinking skills, and a strong sense of self-confidence. You as a candidate must be willing to always learn more and to work as a team player.

Before stepping into the room for the interview firstly have a firm belief in yourself and try to keep calm as much as possible and try to answer each and every with utmost accuracy and confidence.


Hello Everyone! We, Rituparna Guha & Firan Mondal, are delighted to present our Mechanical Engineering articles. We will capture all types of articles and try to explain in the simplest way with a lot of diagrams! Happy Reading....

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