When your heater or air conditioner stops working, it can be disruptive to your daily life. We understand how important it is to have a comfortable home and will respond quickly to fix the issue. Our technicians are highly trained and experienced, so you can rely on Deljo Heating, Cooling & Plumbing to get the job done right the first time.
Our company has been providing top-notch HVAC services to Chicagoland for over 100 years, and our customer satisfaction focus has earned us our stellar reputation. We believe good business is built on relationships, so earning your trust is our priority.
Deljo Heating, Cooling & Plumbing is committed to delivering premier HVAC maintenance, repair, and installation services with every visit for every customer.
HVAC Maintenance
The best way to prolong the lifespan of your heating and cooling system is to schedule regular maintenance. Another advantage of keeping up with maintenance is that your system will run more effectively and efficiently, keeping your home comfortable and your energy bill low.
Ideally, maintenance should be done every spring and fall to ensure peak performance during seasons with extreme temperatures.
Heating & Cooling Repair
From heat pumps and ductless systems to boilers and traditional AC units, Deljo Heating, Cooling & Plumbing has the experience and skill to repair any HVAC system. Our specially trained technicians will diagnose and repair your heater or air conditioner promptly and professionally.
HVAC Installation
All heating and cooling systems eventually break down and wear out, even with the most meticulous care. When your HVAC system needs to be replaced, you can count on Deljo Heating, Cooling & Plumbing to provide the highest caliber of service when replacing or upgrading your system. If you need a new installation, our team can make professional recommendations best suited to your home, needs, and budget.
Emergency HVAC Services
When we say we care about our customers, we mean it – we are only ever a phone call away. Regardless of day or time, when your heater or air conditioner stops working and you need us, we will be there. During extreme weather conditions, a broken HVAC system can put people and pets at risk for illness, count on Deljo Heating, Cooling & Plumbing.
Trusted HVAC in Des Plaines
For over a century our customers have put their trust in Deljo Heating, Cooling & Plumbing for all their heating and air conditioning needs. We invite you to experience the Deljo Difference when your HVAC system needs service in Des Plaines. We promise to meet or exceed your expectations or your money back, so schedule an appointment today.
Recent Jobs and Reviews in Des Plaines, IL
Des Plaines, IL at a glance
Deljo Heating, Cooling & Plumbing has completed 20 jobs in Des Plaines, IL between May 2026 and November 2026.
The most recent job was on November 9, 2026.
Deljo Heating, Cooling & Plumbing has completed 37 jobs in Des Plaines, IL in the last 12 months.
Job Locations and Reviews
Diagnosed and repaired a leaking two-handle bathroom faucet, restoring proper seal and eliminating the leak. Inspected the toilet tank assembly, including the fill valve and flapper chain, and noted mineral staining and sediment buildup within the tank. Cleaned the faucet fixture and verified normal operation of all components.
Installed a new frost-proof hose bib on the exterior brick wall, replacing the corroded existing spigot. Performed a flow test to verify proper water delivery at the spout, and confirmed the fixture is operational and ready for seasonal use.
Performed annual maintenance on the furnace, including inspection of the air handler cabinet, control board, and wiring harness for secure connections and signs of wear or debris. Removed the heavily soiled 16x25x1 return air filter and installed a new pleated filter to restore proper airflow and protect the blower and heat exchanger components.
Installed a new 40-gallon electric tank water heater, including connection of water supply and discharge piping, and verified proper operation. Upgraded the breaker in the electrical panel to the correct amperage to properly support the new unit's electrical load.
Responded to a tanked water heater overheating event in which the high-limit safety had tripped and required manual reset. Inspected the unit and its dedicated double-pole 30-amp circuit breaker at the electrical panel, and identified the heater as a 2008-manufactured State Industries tank, approximately 18 years old and well beyond its typical 8–12 year service life. Recommended replacement due to age and the risk of recurring overheating, corrosion, and leaks.
Performed an on-site evaluation for replacement of an existing steam boiler, inspecting the boiler, burner assembly, gas valve, and associated piping and wiring in the basement mechanical room. Noted rust and corrosion on the burner area piping and fittings, loose and unsecured wiring, and the unit resting on concrete blocks. Also assessed the cast-iron column radiators and valves in the heated space, which showed paint wear and discoloration, to determine system compatibility and scope for the replacement quote.
Performed a scheduled maintenance on a gas furnace under the maintenance agreement, removing the front access panel to inspect the burner assembly, wiring harnesses, and control components. Inspected the blower assembly and found a dusty coating on the squirrel-cage fan wheel, along with mineral buildup and residue on the adjacent metal surfaces, consistent with a humid operating environment. No frost, ice, rust, or visible damage was observed on the unit's exterior or internal components.
Performed annual maintenance on one furnace under the service agreement, including inspection of the blower assembly, where the housing and squirrel-cage wheel showed light dust accumulation and minor surface rust at the seam. Inspected the humidifier reservoir, which showed heavy mineral sediment, discoloration, and microbial-type buildup, indicating the need for cleaning or replacement to ensure proper humidification and indoor air quality.
Performed a scheduled maintenance inspection on the gas furnace, including a borescope inspection of the blower assembly that revealed a moderate accumulation of dust and debris on the squirrel-cage fan blades. Documented the blower and heat exchanger area with photos to record system condition and recommend cleaning as needed to maintain proper airflow and efficiency.
Completed scheduled AC maintenance and replaced malfunctioning thermostat with new Ecobee3 digital unit. Inspected blower wheel assembly and verified proper operation of all HVAC system components.
Responded to callback for AC not cooling and making noise. Upon arrival, found evaporator coil completely frozen over with heavy frost accumulation, measuring 57°F at the coil surface. Inspected electrical components and capacitor connections, which appeared intact with proper wiring configuration. Diagnosed frozen coil as result of restricted airflow due to lack of maintenance. System shutdown to allow coil to thaw before further evaluation could be completed.
Responded to no heat call for furnace less than one year old. Upon inspection, discovered evaporator coil leaking, with coil and air conditioning system being original 16-year-old equipment while furnace had been recently replaced. Documented outdoor condenser unit heavily obstructed by overgrown vegetation around perimeter and protective cage, which restricts proper airflow and reduces system efficiency. Photographed indoor coil area showing PVC condensate drain components requiring attention due to leaking condition. Advised customer that aging coil has failed and requires replacement, noting that 16-year-old equipment has exceeded typical service life expectancy and continuing to repair may not be cost-effective long-term solution.
Returned to complete previously sold maintenance work on residential air conditioning system. Performed blower wheel cleaning to improve airflow efficiency. Installed compressor saver hard start capacitor to reduce inrush current and extend compressor lifespan. Applied AC Renew treatment to system. Verified electrical measurements using clamp meter, confirming proper amperage draw of 52.0 amps. Inspected existing dual capacitor and newly installed Pro Tech compressor saver capacitor, ensuring secure mounting and proper wire connections. All components functioning within normal operating parameters upon completion.
Conducted on-site evaluation for installation of four mini-split systems in residential property. Assessed interior room dimensions, wall conditions, and optimal placement locations for indoor air handler units. Evaluated existing electrical infrastructure at main service panel to determine capacity and compatibility for powering multiple mini-split condensing units and air handlers. Documented site conditions including room layout, window locations, baseboard heating configuration, and electrical panel accessibility. Noted evidence of moisture concerns near electrical panel requiring attention prior to installation. Provided comprehensive estimate for complete multi-zone mini-split HVAC system installation.
Responded to no airflow complaint on aging air conditioning system. Upon inspection, found evaporator coil completely frozen with heavy ice accumulation, restricting all airflow through the unit. Documented frozen coil condition showing significant frost buildup across aluminum fins and refrigerant lines. System shutdown was necessary to allow complete defrost cycle before further diagnosis could determine root cause, which typically indicates restricted airflow from dirty filter, low refrigerant charge, or failed blower motor components.
Conducted comprehensive evaluation of existing Rheem Criterion II gas furnace system for full replacement estimate. Unit assessed is a 25+ year old installation showing signs of age-related wear and obsolescence. Performed detailed measurements of existing equipment dimensions and clearances within utility closet installation space to determine replacement specifications. Documented current system configuration including furnace cabinet dimensions, supply and return air plenum connections, gas line routing, venting arrangement, and electrical connections. Installation location provides favorable working conditions with ground-level access eliminating need for ladder work. Photographed existing equipment condition, spatial constraints, and all utility connections to support accurate equipment sizing and installation planning for proposed replacement system.
Completed comprehensive HVAC maintenance agreement service on non-guaranteed system including one air conditioning unit, one furnace, and water heater. Performed standard inspection protocol, replaced air filter showing moderate dust accumulation, and verified system temperatures with supply air reading 74.2°F. All equipment operating within normal parameters at time of service.
Responded to service call for leaking outside faucet. Upon inspection, identified failed washer and worn internal components causing water seepage from the hose bib spout. Shut off water supply, disassembled the outdoor faucet assembly, and replaced deteriorated rubber washer and stem packing. Reassembled unit, restored water supply, and tested for proper operation and leak-free performance. Verified no additional leaks at wall penetration point and confirmed solid connection to copper supply line.
Completed preventive maintenance agreement service on residential air conditioning system. Performed comprehensive inspection of outdoor condenser unit, verified proper electrical connections at disconnect box and service panels, and conducted standard system performance evaluation. Unit operating within normal parameters upon completion of scheduled maintenance visit.
Completed comprehensive preventive maintenance agreement service on single-zone HVAC system consisting of one outdoor condensing unit and one air handler. Performed thorough inspection of condenser unit electrical components including capacitor, contactor, and associated wiring connections; verified proper operation and secured all electrical connections. Inspected thermostat controls and confirmed proper communication between control system and equipment for accurate temperature regulation and system cycling.
