Marengo, IL Heating & Cooling

Full-Service HVAC Contractor for Marengo, IL

Marengo is a city in McHenry County, and we reach it from our Elgin shop with the same trucks, parts and technicians that cover the rest of the Fox Valley. Furnace, air conditioner, heat pump and boiler repair, replacement and maintenance on every major brand, with the phone answered 24 hours a day.

Call (847) 224-2420
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  • Furnace, AC, heat pump and boiler
  • Nicor Gas Contractor Circle member
  • ComEd Heat Pump-Trained
  • 24/7 emergency service

One Contractor for the Whole System

Heating

Furnaces and Boilers

Gas furnace repair, replacement and tune-ups, plus hot-water and steam boiler service for radiator and baseboard homes.

Cooling

Air Conditioners and Heat Pumps

AC repair on any brand, R-32 replacements, and cold-climate inverter heat pumps that heat and cool from one unit.

No ducts

Ductless Mini-Splits

Daikin single and multi-zone systems for additions, bonus rooms and older homes that were never ducted.

Full-service means one call whether the furnace quit, the air conditioner is icing up or the boiler is banging. Our qualified and experienced technicians hold EPA 608 Universal and NATE certifications in Air Conditioning Installation and Gas Heating Installation, and carry Daikin and Amana factory training. Reach us any hour at (847) 224-2420.

Marengo Homes, From the Original Townsite to New Subdivisions

Marengo was settled in 1835, incorporated as a village in 1857 and became a city in 1893. About 7,600 people live here now (7,568 in the 2020 census), with US-20, Route 23 and Route 176 meeting in town. That history shows up in the houses, and it changes what the right HVAC answer is from one block to the next.

Older homes

Near the original townsite

Houses a century old or more often come with older boilers, tight basements and ductwork that was never sized for air conditioning. We repair hot-water and steam boilers, and a Daikin ductless system can cool rooms that a duct run can’t reach.

Newer subdivisions

Built since the 1990s

Marengo’s growth picked up after 1990, and the furnaces and air conditioners in the earlier of those houses are now at the age where replacement is worth planning before the first cold snap forces it.

Outside city limits

Rural Marengo addresses

Not every address around Marengo is on the same gas main or served by the same utility. Give us the address and we will check what is available, including whether a heat pump or dual-fuel setup makes more sense, before we quote.

The City of Marengo lists ComEd for electric and Nicor for natural gas, so the CY2026 ComEd and Nicor instant discounts described below apply to most homes in town. The city’s building department does not list a stand-alone furnace or air-conditioner permit application online, so before an installation we confirm with the City of Marengo Building Department whether your job needs a permit and file it when a permit is requested and required*. Start with furnace replacement, AC replacement, boiler repair or ductless mini-splits, or call (847) 224-2420. We also serve nearby Huntley, Hampshire and Pingree Grove.

24/7 Emergency HVAC Service in Marengo

No heat below freezing, no cooling in a heat wave, or a boiler leaking on the basement floor: those do not wait for business hours, and neither do we. Check the thermostat, the breaker and the furnace door switch first; if that does not fix it, call (847) 224-2420 and we will quote the after-hours visit on the phone before we dispatch.

If you smell gas, leave the house right away, call 911 from outside, and call your gas utility’s emergency line from outside before calling us. See emergency furnace repair, emergency AC repair and emergency boiler repair for what counts as an emergency and what can wait until morning.

Furnace Repair and Replacement in Marengo

Furnaces here run hard from November through March against design temperatures near 0°F, and the first cold snap is when the weak ones fail. We repair every major brand. Igniters, flame sensors, pressure switches, inducer motors and control boards are the common failures, and most of those repairs typically land between about $150 and $900.

A cracked heat exchanger, or a repair bill past half the cost of a new unit on a furnace over 15 years old, is where furnace replacement makes more sense. A 95% or 97% AFUE condensing furnace qualifies for a CY2026 Nicor Gas instant discount of $150 or $225, or $200 or $275 with a qualifying smart thermostat on the same invoice.

Cooling, Heat Pumps and Boilers

Humid summers

AC Repair and Replacement

Capacitors, contactors and fan motors commonly run $150–$700. Refrigerant leaks and compressors can run into the thousands, where the repair-or-replace conversation starts.

CY2026 ComEd discounts

Heat Pump Installation

A qualifying ducted cold-climate heat pump such as the Amana S-Series gets $900–$2,000 off from ComEd, or pair it with a gas furnace as a dual-fuel system.

Hot-water & steam

Boiler Service

Cold radiators, kettling, pressure swings and lockouts repaired on any brand. Laars boilers installed, with $350 or $500 CY2026 Nicor discounts on qualifying units.

R-410A is being phased down and its price is rising, so new cooling equipment uses R-32. See AC repair, AC replacement, heat pump installation, dual-fuel systems and boilers.

What a Service Call Costs in Marengo

Repairs start with a flat diagnostic fee to find the problem. During office hours (8 a.m. to 5 p.m., Monday through Friday) the service call is $130; weekday evenings after 5 p.m. it is $180, and nights, weekends and holidays are $260. Each includes 30 minutes of travel and 30 minutes of diagnostics, and parts are extra. Once we know what failed, you get a flat-rate repair price and approve it before any work starts. We file the permit when a permit is requested and required*.

After-hours and emergency service calls are priced higher than business-hours calls, and we quote that on the phone before we dispatch. Replacement quotes are free, written, sized from the house rather than the old nameplate, and include the discounts. Financing prequalifies in about 2 minutes with no impact to your credit score.

Marengo HVAC Services

Heating, cooling, boilers, ductless and indoor air quality for Marengo from one contractor. Each service below has its own page.

24/7 no heat

Furnace Repair in Marengo

No heat, short cycling or a furnace that clicks and never lights, diagnosed and repaired on any brand.

CY2026 Nicor discounts

Furnace Replacement in Marengo

95% and 97% AFUE furnaces with the CY2026 Nicor Gas discount taken off the invoice, quoted free and in writing.

All brands

AC Repair in Marengo

Capacitors, contactors, fan motors and refrigerant leaks on every major brand, priced before the work starts.

Free quotes

AC Replacement in Marengo

R-32 equipment, sized from the house, with a free written quote and the old unit hauled away.

CY2026 ComEd discounts

Heat Pump Installation in Marengo

Cold-climate inverter heat pumps, including Amana S-Series, with $900–$2,000 off on qualifying ducted systems.

Hot-water & steam

Boiler Repair in Marengo

Cold radiators, banging, pressure problems and lockouts on hot-water and steam boilers of any brand.

No ductwork

Ductless Mini-Split Installation in Marengo

Daikin single and multi-zone systems for additions, bonus rooms and houses that were never ducted.

AprilAire

Indoor Air Quality in Marengo

Whole-home humidifiers, dehumidifiers and media air purifiers installed on your existing furnace or air handler.

Any hour

Emergency Furnace Repair in Marengo

No heat below freezing is an emergency. We answer around the clock and quote the after-hours call before we roll.

Any hour

Emergency AC Repair in Marengo

AC not cooling in a July heat wave, handled the same day whenever we can get there.

$240 / year

Maintenance Plan in Marengo

Spring and fall tune-ups on one system, plus one free business-hours service call and 5% off services.

Also available in Marengo: air handler repair, smart thermostat installation, humidifier installation, dehumidifier installation, air purifier installation, duct cleaning and airflow diagnostics and dual-fuel heat pump and furnace systems.

Rebates in Marengo

The City of Marengo lists ComEd and Nicor as its utilities, and both instant discounts are applied right on your invoice at installation for qualifying homes and equipment: $900–$2,000 on a qualifying ducted heat pump, $500 or $1,000 on a qualifying ductless system, $225 on a furnace at 97%+ AFUE or $150 at 95% AFUE, and $350 on a qualifying 95% AFUE boiler or $500 on a combination boiler. There is no application and nothing to mail in.

See CY2026 ComEd Instant Discounts and Nicor Gas Instant Discounts for the qualifying equipment, or ask for the numbers on your free quote.

Marengo HVAC FAQs

Do you really cover Marengo from Elgin?

Yes. Marengo is inside our McHenry County service area, and our technicians reach it from our Elgin shop for repairs, replacements, maintenance and 24/7 emergency calls.

Do I need a permit to replace a furnace or air conditioner in Marengo?

We confirm with the City of Marengo Building Department whether your job needs a permit and file it when a permit is requested and required.

Do CY2026 ComEd and Nicor Gas discounts apply in Marengo?

The City of Marengo lists ComEd and Nicor as its electric and gas suppliers, so for most homes in town both instant discounts come off the invoice at installation. If your address is served by a different supplier, call and we will check before we quote.

What does an after-hours call cost in Marengo?

After-hours and emergency service calls are priced higher than business-hours calls, and we quote the call on the phone before we dispatch. Repairs are flat-rate and approved by you before any work starts.

Do you work on boilers in Marengo?

Yes. We repair hot-water and steam boilers of any brand, install Laars boilers, and handle the radiators, baseboard and controls that go with them.

Can you cool an older Marengo house that has no ductwork?

Yes. A Daikin ductless mini-split cools and heats individual rooms with no ducts, which suits older homes with boiler or radiator heat. We also repair the boiler side, so you can keep the heating you have and add cooling.

What if my Marengo address is outside the city limits?

We still serve it. Rural addresses around Marengo are inside our McHenry County service area. Which utility discounts apply depends on who serves your address, so give us the address when you call and we will check before we quote.

Do you service all brands, and how do I book?

Yes. We install Amana and Daikin Ductless and repair every major brand of furnace, air conditioner, heat pump, boiler and mini-split. Call (847) 224-2420 any hour, or book online and pick a time that works for you.

Other Towns We Serve

Don’t see your town? Call (847) 224-2420. View all service areas.

Your Marengo HVAC Team

Full-service heating and cooling for Marengo from a team based in Elgin.

Call (847) 224-2420
Book Online

Planning a replacement? Request a free quote or see financing options.

Discount amounts reflect the 2026 Nicor Gas Energy Efficiency Program for qualifying equipment installed January 1 through December 31, 2026, and are subject to change or cancellation due to funding limits. Rest Assured HVAC LLC is an independent contractor and is not affiliated with or endorsed by Nicor Gas.

Discount amounts reflect the 2026 ComEd Energy Efficiency Program for qualifying equipment and are subject to change or cancellation due to funding limits. Rest Assured HVAC LLC is an independent contractor and is not affiliated with or endorsed by ComEd.

*Pulling a permit is the homeowner’s responsibility. Ask us to, and we’ll file it under our own license wherever the local jurisdiction requires one for the work.