Deljo Heating & Ac Repair

How Do Furnaces Work?

We rely on our furnaces to provide us with heat when the brisk Chicago temperatures once again drop into single digits. But do you know exactly how your furnace is able to provide you and your family with comfort? At Deljo Heating, Cooling & Plumbing, we provide furnace installation in Chicago to make sure that the worry of your home being cold is never an issue.

Furnaces Are the Most Common Furnace Type

There are multiple ways that you can heat your home, however, a furnace is the most common way to do so. Your furnace may be heated in different ways, including a gas-powered central air system that operates by heating one area and distributing it throughout your home via ductwork and vents. The two main components of your furnace include the control system, gas valves, heat exchanger, blower and duct and ventilation systems.

The Importance of the Thermostat and Gas Valve

As soon as your furnace receives a signal from the thermostat, it starts to work. Some furnaces are also programmed to detect the current air temperature and kick on if the temperature is too low. When your furnace turns on, the gas valve ignites the burner underneath the combustion chamber. Then, the heat moves to the heat exchangers and circulates through a set of looped tubes, transferring the heat into the air.

Energy Efficiency

One aspect of furnace installation in Chicago is energy efficiency. You want to invest in a furnace that will be as energy efficient for your family as possible. Energy efficiency is dependent on your furnace’s Annual Fuel Utilization Efficiency (AFUE) that tells you how much fuel is used and how much fuel is lost. For example, if you have an 80 percent AFUE furnace, 80 percent of the fuel is used to heat your home and the remaining 20 percent is lost. Low-efficiency furnaces typically have an AFUE rating between 50 and 70 percent while high-efficiency furnaces typically have an AFUE rating above 90 percent.

Call our professionals at Deljo Heating, Cooling & Plumbing if you’re in need of a furnace installation in Chicago, and we will be happy to help make sure that you and your family have an efficient, affordable furnace to get you through not only this winter, but many winters to come! Contact us today to get started.

Our Service Areas

Contact Deljo Heating, Cooling & Plumbing today. We look forward to hearing from you and helping out with all your indoor comfort needs.

Client Testimonials

Read the opinions of our satisfied customers.

Call Now 773-280-8251 Schedule Your Service

This was my first time as a Deljo customer, and I was very pleased. My technician, Giovanni, was very thorough and diligent. He serviced my furnace and identified a faulty sensor that was causing the unit to shut itself down. Deljo ordered the part, and Giovanni replaced it a few days later. Overall, the team at Deljo was great. The dispatcher kept me informed about Giovanni’s arrival time, and the supervisor assisted Giovanni when he was diagnosing the problem with the furnace. I highly recommend Deljo.

Paul D. 10/15/2026

I’ve used Deljo for over 10 years now and they always do a good job. Izzy was the technician for this visit and he did an excellent job with my winter maintenance on my multiple units in the household. He also addressed an issue while cleaning the furnace blower wheel. His communication was clear and concise with what he planned to do to address the issue quickly. He was confident and I had 0 concerns or questions. Great job Izzy!

Jeff S. 10/14/2026

Paul was great! Arrived on time and completed maintenance on my humidifier, tankless water heater, and two furnaces. All work was performed under my Gold Star maintenance program, so all maintenance charges were covered. Paul did provide a few proposals for additional services on furnace & tankless water heater, but those were emailed to me for further consideration. Paul was friendly, knowledgeable, and answered all my questions.

Jack N. 10/12/2026

Gabe did an excellent job with our annual service visit. He arrived in the early part of our service window, was friendly and knowledgeable, and got the work done in a very reasonable amount of time. I have great confidence in Deljo, and am a long-time customer.

Ruth C. 10/9/2026

I’ve been using Deljo for 20 years for HVAC but now venture into enlisting their plumbing services. Bashar was very courteous, efficient & informative, and I’d definitely request him again for the next plumbing job. Great experience!

Christopher R. 10/2/2026

Working with Deljo is always a good experience, and today’s appointment with Izzy was no different. He was able to come early which actually worked better with our schedules, but called me ahead of time to make sure that was okay. He was friendly and knowledgeable when he explained the work he had done during his visit and our options for fixes. He was also able to schedule a quote appointment for us while he was still here. We would highly recommend working with Izzy and the Deljo team!

Lauren H. 9/25/2026

Drew performed the seasonal maintenance on my AC. It needed some repairs and updates and he was able to fix everything at the same appointment. He also noticed issues with the hot water heater and we were able to get ahead of that, as well.

Emily W. 9/11/2026

I would leave six out of five stars if I could! My technician Jorge went above and beyond on his service. There was buildup in the rental property’s toilet from the previous tenant. One maintenance person did a surface level job of cleaning but did not fully remove the obstruction. Jorge went above and beyond and came to a solution and even explained the perpetual problems older toilet models can cause. Moving forward with this insight, I can perform my own upkeep the previous tenant did not. Thank you kindly!

Kayla K. 9/15/2026

We just had our new boiler installed by Jonathan and Carlos. First rate work! They arrived on time, removed the old boiler, installed the new unit, and explained the features. Both guys were pleasant. Bring on the cold this winter! We are ready thanks to the team from Deljo.

Edward B. 6/26/2026

Deljo’s heating and cooling team was awesome to work with. As a first-time homeowner, I really appreciated how clearly they explained everything and answered all my questions. From the quote to the install and follow-up, the service was top-notch. Highly recommend!

Lindsey A. Chicago, IL

Matt did an amazing job. He serviced our home and our rental property. He gave us options to help our systems run more efficiently. He also told us about Deljo’s new plumbing inspection which was very affordable. He is great!

Jordan R. Chicago, IL

We had a problem with our Humidifier and called Deljo. Jesus came out to help and was amazing. He was extremely knowledgeable, detail oriented, and super courteous. Amazing customer experience!

Jeff C. Chicago, IL

Jordan and Jesus were extremely helpful and knowledgeable! We would 100% work with them and have them back. They were both very professional and efficiently fixed our heating system.

Emily L. Chicago, IL

Shout out to Ernesto for coming out and servicing our furnace and air con. Deljo provides a great service and glad to trust them with our HVAC for our small business.

Lauren H. Chicago, IL