About aircondlounge.com

aircondlounge provides solutions to heating, ventilation and air conditioning (HVAC) for homeowners and engineers around the world through blog articles. Also provide guidance to hot water system and construction project management.

Yu Chang Zhen is the founder and author of aircondlounge. He believes in the mission to accelerate the world's transition to sustainable energy. He contributes to the mission by creating HVAC content on the internet. He trusts that through education, the impact of HVAC on the environment can be reduced.

“Online learning is a great way for people around the world to gain access to useful information thereby improving their skills and making the world a better place.”

Hi, my name is Yu Chang Zhen. People call me by my surname, Yu. I live in Malaysia, a very hot and humid country. I'm an Engineer working in the air conditioning construction industry for more than 7 years. I started this website in the year 2020, hoping to provide useful information to people around the world.


For many years, I've seen many air conditioning systems that are poorly designed, installed and maintained. These problematic air conditioning systems are wasting so much energy. At the same time, I've seen many junior engineers struggling because of not having sufficient training and guides.

While mobile phones and laptops have rapid technology development, the construction industry is still doing the same thing every day. At the construction site, people are still managing works manually using papers and whiteboards.

Although there are many handbooks, guidelines, courses and seminars out there, most junior engineers simply can't afford them unless they are sponsored by the company they are working in. However, most companies are doing business and not charity; they won't send their engineers to attend courses and seminars for nothing.

Hence, I created this website for junior engineers and basically anyone to gain access to useful information that I've learned over years of my working experience as well as new information that I've gained speaking with industry leaders.


Apart from helping individuals, I'm actually into climates and global warming issues. Experts say that it is inevitable that Earth is going to warm up much more than they anticipated unless everyone in the world joins forces to reduce carbon emissions.

Heating and cooling in buildings are one of the major contributors to global warming. However, inefficient heating and cooling systems are making things worse.

“The problem is, today's consumers are not buying the most efficient ACs.”

International Energy Agency (IEA)

According to IEA research, most people are not using the most efficient air conditioners. They projected that space cooling energy demand will be cut by half if most people are using efficient air conditioning systems.

In addition, IEA also expects air conditioners to be the second-largest source of global electricity demand growth after the industry sector and the strongest driver for buildings by 2050.

I'm hoping that by making useful information accessible to people around the world, more heating and cooling systems can run efficiently and thus, power consumption can be reduced thereby carbon emissions can be reduced and global warming can be turned around.


I started my first job as a Project Engineer in a small company specialized in building district cooling plants with thermal energy storage back in the year 2013. I was assigned to assist a few project managers on tender, design and submission work. Back then, I mostly just follow managers around meeting clients and taking notes.

After a few months, I learned to become more independent and that's when I and two other project engineers, who joined the company about the same time as me, were assigned to a hospital energy audit and retrofit project.

While working on the hospital project, I got to use many cool measuring devices such as temperature and humidity data loggers, ultrasonic flow meter and pitot tube. Back then, I was primarily responsible for data analysis and reporting.

In the following year, I worked on a primary school air conditioning system construction project. After the project was completed, I decided to move on to another company.

Nearly two years after my college graduation, I still worked as a Project Engineer. In my new company, I was assigned to work on two luxury high-rise residential towers simultaneously. But, the project had already started and we were behind the schedule. Thus, I was having a very difficult time trying to adapt and catch up with the schedule.

At that time, I was managing more than 30 direct workers and two sub-contractors at peak with over a thousand air conditioners and mechanical fans waiting to be installed and commissioned.

It was very stressful because I barely have any experience in high-rise building constructions. I was staying up until late at night almost every day during the commissioning stage. Furthermore, I had to do many tests by myself as workers were generally unable to handle instruments, causing delays on some of my RFIs and submissions.

Out of all, the bomba test is the most critical part for me. I teamed up with a few general workers to finish up the entire smoke spill and pressurization system as my supervisor had to bring another team to commission air conditioners for the residential units.

Fortunately, we were able to pass the bomba fire safety test in one shot and got all air conditioners tested and commissioned thereby minimizing the delay and ultimately obtaining the certification of practical completion (CPC) for the project.

Although the project was very difficult for me, I grew a lot since then. I learned time and stress management as well as people and relationship management.

In the same year, my colleagues and I went to Beijing, China to attend one of the largest HVAC&R exhibitions in the world. The exhibition center is so big that we had to split into 4 teams and stay for 3 days. Every night, we'll exchange the information and knowledge gained from each team.

Since we are in China, we wouldn't want to waste it. So, we took the opportunity to go around Beijing and visited some tourism places like Great Wall, and Muzeum before flying back to Malaysia.

I have many great memories of the trip to Beijing and we learned so many new things from the HVAC&R exhibition.

After the two residential towers were handed over, my service team took over and I was transferred to work on another high-rise building but this time, it's an office tower. Remarkably, I was told that it is the first-ever hybrid chiller project in Malaysia. It has a whopping 54 units of hybrid chillers sitting on the roof. My colleagues and I always talk about it during tea breaks.

The project also involved a few industry experts to guide all of us involved in the project on energy efficiency and green building codes. I was lucky to be able to join a few factory visits with them and it was eye-opening for me.

After more than 4 years of working, I was promoted to become a Senior Project Engineer. I was doing multiple design projects including value engineering work, 3D Revit drawings production and the installation of VRF air conditioning system for high-end retail stores. Meanwhile, I also reported directly to the managing director on business development work.

Though I like my company at that time, I decided to challenge myself a year later. I took an offer from another company and became a Project & Service Manager at the age of 28 where I was working primarily on hot water heat pump systems. For about 2 years, I was serving hundreds of customers every week, solving their hot water and heat pump issues before I decided to quit and start this website.

There is so much more I want to share but this is getting too long. If you want to know more details about me and what I do previously, kindly view my LinkedIn profile here. I'm a Bachelor's Degree holder, majoring in Mechanical Engineering. I created this website to leverage my working experience and knowledge to help people around the world.


I don't spend a lot of time attending courses and seminars to get certificates for the sake of getting certified and the proof of credentials. These are what I have.


I've handled not many projects compared to people who worked in the HVAC industry for 10-20 years. However, I manage each and every project in details; almost every aspect of the project from costing to commissioning and after-sales service.

SJKC Wangsa Maju
Village Grocer, Tamarind Square
BookXcess, Tamarind Square
Menara TCM
Tropicana Gardens Arnica & Bayberry


From my work, I learned many air conditioning systems, both residential and commercial. Unfortunately, I didn't have much experience in industrial applications. Nonetheless, these are the systems that I know and had experience with.

Single Split
Multi Split