Weil-McLain SlimFit Commercial Condensing Boiler Installation Chicago
Weil-McLain Condensing Commercial Boilers
SlimFit® Commercial Condensing Gas Boiler
High-efficiency condensing design. 95% AFUE. 399,000–1,000,000 BTU/hr. Fits through standard doorways — ideal for Chicago mechanical room retrofits.
Weil-McLain SlimFit® — Chicago's High-Efficiency Retrofit Boiler
The Weil-McLain SlimFit® is a high-efficiency condensing commercial gas boiler purpose-built for retrofit installations in existing Chicago buildings. Its defining feature is a narrow profile that fits through a standard 32-inch doorway — eliminating the need for wall demolition or crane lifts that conventional large commercial boilers require.
With 95% AFUE and a modulating burner, the SlimFit® dramatically reduces fuel consumption compared to the atmospheric boilers it replaces. Four models from 399,000 to 1,000,000 BTU/hr cover mid-size commercial buildings, multi-unit residential properties, schools, and institutional facilities throughout Chicago.
D's Air & Heating, Inc. installs the SlimFit® throughout Chicago and the southwest suburbs. We handle all City of Chicago commercial mechanical permits, PVC venting, system piping, controls, and startup — and register your Weil-McLain warranty before we leave the job.
Why D's Air & Heating, Inc. Installs the SlimFit®
95% AFUE Condensing
High-efficiency condensing design recovers heat from flue gases — dramatically reducing fuel costs in Chicago's long heating season.
Fits Through Standard Doors
The SlimFit's narrow profile is engineered to pass through a standard 32-inch doorway — the critical advantage for Chicago mechanical room retrofits.
Direct Vent / PVC
Vents with standard PVC pipe — no chimney required. Ideal for Chicago buildings without existing flue infrastructure.
399K–1,000,000 BTU/hr
Four models cover mid-size commercial buildings, multi-unit residential, and institutional facilities throughout Chicago.
Modulating Burner
Modulating operation matches output to actual heating demand — reducing short-cycling and improving comfort in variable-load Chicago buildings.
Weil-McLain Warranty
Backed by Weil-McLain's limited warranty. D's Air & Heating, Inc. registers your warranty at startup.
SlimFit® — Models & Specs
| Model | BTU/hr Input | Efficiency | Fuel | Venting | Installed Price |
|---|---|---|---|---|---|
| SlimFit 399 | 399,000 | 95% AFUE | Natural Gas / Propane | Direct Vent / PVC | Call for Pricing |
| SlimFit 500 | 500,000 | 95% AFUE | Natural Gas / Propane | Direct Vent / PVC | Call for Pricing |
| SlimFit 750 | 750,000 | 95% AFUE | Natural Gas / Propane | Direct Vent / PVC | Call for Pricing |
| SlimFit 1000 | 1,000,000 | 95% AFUE | Natural Gas / Propane | Direct Vent / PVC | Call for Pricing |
SlimFit 399
399,000 · 95% AFUE
Natural Gas / Propane · Direct Vent / PVC
Call for Pricing
SlimFit 500
500,000 · 95% AFUE
Natural Gas / Propane · Direct Vent / PVC
Call for Pricing
SlimFit 750
750,000 · 95% AFUE
Natural Gas / Propane · Direct Vent / PVC
Call for Pricing
SlimFit 1000
1,000,000 · 95% AFUE
Natural Gas / Propane · Direct Vent / PVC
Call for Pricing
*Local taxes may apply. Call for current installed pricing.
What's Included in Every SlimFit® Installation
- Complete removal and disposal of existing boiler
- New Weil-McLain SlimFit® boiler — properly sized for your building
- PVC direct-vent flue installation (no chimney required)
- Gas supply line connection and pressure test
- System piping, supply and return connections
- Expansion tank, pressure relief valve, and air separator
- Thermostat and zone control wiring
- City of Chicago commercial mechanical permit (when required)
- Full system startup, combustion analysis, and efficiency verification
- Weil-McLain warranty registration
Weil-McLain Boiler Installation & Service Experts
D's Air & Heating proudly provides professional Weil-McLain boiler installation, replacement, repair, maintenance, and emergency service throughout Chicago and surrounding communities. Weil-McLain is recognized as one of the most trusted names in the boiler industry, delivering reliable heating solutions for residential, commercial, steam, and hot water applications.
Our experienced boiler technicians install and service a wide range of Weil-McLain commercial equipment. Whether you need a new Weil-McLain boiler installation Chicago businesses rely on, complete boiler replacement, annual maintenance, or emergency repair service, D's Air & Heating has the expertise to keep your commercial heating system operating safely and efficiently.
From small commercial buildings to large boiler plant projects, D's Air & Heating delivers quality workmanship, expert system design, and dependable customer support backed by industry-leading Weil-McLain technology and warranty protection. Our Weil-McLain boiler repair Chicago commercial customers trust us for fast diagnostics, genuine parts, and lasting fixes.
Contact D's Air & Heating today at (773) 940-0965 to schedule your free estimate for Weil-McLain boiler installation, replacement, maintenance, or repair services.
Get a SlimFit Commercial Boiler Estimate
D's Air & Heating, Inc. installs the Weil-McLain SlimFit throughout Chicago and the southwest suburbs. Call (773) 940-0965 or book online for a free commercial estimate.