Furnace Replacement in Knollwood, Illinois
Furnace Replacement in Knollwood typically costs $4,500-$9,000 installed in 2026, depending on home size and efficiency tier.
Knollwood is unincorporated Lake County - a pocket of postwar ranches and split-levels between Lake Bluff and Libertyville. The houses are modest and mostly single-story, which sounds like a simple furnace job until you look at where the ductwork runs.
| Smaller homes (under 1,500 sq ft) | $3,800-$7,900 |
| Typical homes (1,500-2,500 sq ft) | $4,500-$9,000 |
| Larger homes (2,500-4,000+ sq ft) | $5,000-$11,900 |
Final pricing depends on system size, efficiency, and home configuration. Every quote is written and itemized after a free in-home estimate, with available utility rebates factored in. See current North Shore rebates or get an instant ballpark estimate.
Furnace Replacement for Knollwood homes
Much of the distribution here is original, single-zone, and routed through crawl spaces where the duct insulation has sagged, torn, or disappeared entirely. A furnace replaced without addressing that will underperform its rating no matter what the label says, because a meaningful share of the heat you paid for is warming the crawl space. We inspect the runs, quote sealing and re-insulating where it is needed, and size the new furnace to the house rather than to the old nameplate - which in a well-sealed postwar ranch is usually a smaller unit than the one coming out.
Several Knollwood properties are on well and septic, so a condensing furnace's condensate line needs a site-specific plan rather than an assumption. Our installers work that out before the day, run PVC venting to code, verify the return path, test combustion, and haul the old unit away. The warranty is registered on the spot and we walk you through the Nicor rebate your efficiency choice qualifies for, so the high-efficiency upgrade costs less than the sticker suggests.
When Knollwood homeowners call us for this
- System is 15+ years old or out of warranty
- A repair would cost a large share of a new unit
- Rising energy bills or uneven comfort
- Repeated breakdowns in a single season
- Phased-out refrigerant (older R-22 AC)
- Planning ahead before a full failure
Why Knollwood homes need replacement planning
Knollwood is unincorporated Lake County, a small pocket of postwar ranches and split-levels between Lake Bluff and Libertyville. The houses are modest and mostly single-story, which sounds simple until you look at the ductwork: much of it is original, single-zone, and run through crawl spaces where the insulation has sagged or disappeared. A furnace replaced without addressing that duct loss will underperform its rating no matter what the label says. Several of these properties are also on well and septic, so anything involving a condensate line or a heat pump needs the site looked at rather than assumed.
Talk it through - (847) 752-4418Neighborhoods we cover in Knollwood
Our process
- 1Free in-home estimate
A comfort specialist comes to your Knollwood home, measures the space, checks ductwork and venting, and explains options and honest price ranges in writing - no charge, no pressure.
- 2Right-sized equipment
We size the system with a proper load calculation and choose efficiency levels that qualify for the utility rebates you're eligible for.
- 3Professional installation
Licensed, insured installers remove the old system and install the new one to spec.
- 4Rebates, registration & follow-up
We register the warranty, hand off the utility rebate paperwork, and confirm everything is running right.
Frequently asked - Furnace Replacement in Knollwood
How much does furnace replacement cost in Knollwood?
Furnace Replacement in Knollwood typically runs $4,500-$9,000 installed, depending on system size, efficiency, and how the home is configured. We provide a written, itemized estimate from a free in-home visit for every Knollwood project - and factor in the utility rebates you qualify for.
Do you serve all of Knollwood?
Yes. We cover every neighborhood in Knollwood, including Knollwood, Lake Bluff border, Rockland Road corridor, Route 176 area and surrounding areas.
Are you available 24/7 for emergencies in Knollwood?
Yes. We run a 24/7 line across Knollwood for no-heat and no-cool emergencies and can prioritize dispatch.
What kinds of systems do you commonly replace in Knollwood?
In Knollwood we regularly work with Postwar ranch forced-air systems, Original single-zone ductwork, Crawl-space furnaces, High-efficiency furnaces, Heat pumps. We match the approach to the home's age, ductwork, and venting.
Furnace Replacement guides
Looking for the full picture on Furnace Replacement or everything we do in Knollwood? Explore those pages, or call (847) 752-4418 for a free estimate today.