359 HVAC contractors ranked by CR ScoreUpdated 0 paid placements in this rankingHow we rank →
Best overall in Marengo: Black Diamond Plumbing & Mechanical Inc., CR Score 92/100; 4.9★ from 6,580 Google reviews; open 24/7.
Best for emergencies (open 24/7): Woodstock Heating, Cooling & Electrical, posts 24/7 hours; ranked #2 of 359.
Most-reviewed: Lifeline Plumbing, Heating & Cooling, 3,222 Google reviews at 4.9★, the most of 359 ranked after Black Diamond Plumbing & Mechanical Inc.; ranked #4.
Rankings can't be bought. Contractors can't pay to change their rank or score. How we rank
359 Marengo HVAC contractors are ranked here by CR Score, from 8 published factors. 180 are open 24/7, 264 open Saturdays and 221 open Sundays, based on posted hours. The median Google rating is 4.9★ across 359 rated businesses.
| Rank | Business | CR Score | Google rating | Based in | Hours | Best for |
|---|---|---|---|---|---|---|
| 1 | Black Diamond Plumbing & Mechanical Inc. | 92 | 4.9★ (6,580) | McHenry, 17 mi away | 24/7 | Overall |
| 2 | Woodstock Heating, Cooling & Electrical | 91 | 4.9★ (1,222) | Woodstock, 10 mi away | 24/7 | Emergencies |
| 3 | GSHA Services, LTD | 91 | 4.9★ (747) | Woodstock, 10 mi away | 24/7 | — |
| 4 | Lifeline Plumbing, Heating & Cooling | 90 | 4.9★ (3,222) | Elgin, 20 mi away | 24/7 | Most reviews |
| 5 | 24HR Home Comfort Services | 90 | 4.9★ (1,374) | Lake in the Hills, 17 mi away | 24/7 | — |
| 6 | G & R Heating and Air | 90 | 4.8★ (2,067) | Gilberts, 16 mi away | 24/7 | — |
| 7 | Climate Control Services LLC | 89 | 5.0★ (776) | Elgin, 18 mi away | 24/7 | — |
| 8 | Leith Heating and Cooling Inc. | 89 | 5.0★ (784) | Elgin, 18 mi away | 24/7 | — |
| 9 | Kustom Heating and Cooling | 89 | 5.0★ (1,021) | Elgin, 21 mi away | 24/7 | — |
| 10 | Legacy Home Services | 89 | 4.9★ (571) | Crystal Lake, 15 mi away | 24/7 | — |
Ordered by CR Score, a 0–100 score from 8 published factors. Paid placement never changes the order.
Scores below: based on 6 of 8 factors; credentials and recency not yet collected. Hatched segments mark factors we don't have yet.
Ranked #1 because of its Google rating and review volume: 4.9★ from 6,580 Google reviews, the most Google reviews on this list (6,580).
Based in Woodstock, 10 mi away
Ranked #2 because of its Google rating and availability: 4.9★ from 1,222 Google reviews, open 24/7.
Based in Woodstock, 10 mi away
Ranked #3 because of its Google rating and availability: 4.9★ from 747 Google reviews, open 24/7.
Based in Elgin, 20 mi away
Ranked #4 because of its Google rating and availability: 4.9★ from 3,222 Google reviews, open 24/7.
Based in Lake in the Hills, 17 mi away
Ranked #5 because of its Google rating and availability: 4.9★ from 1,374 Google reviews, open 24/7.
Based in Gilberts, 16 mi away
Ranked #6 because of its Google rating and availability: 4.8★ from 2,067 Google reviews, open 24/7.
Based in Elgin, 18 mi away
Ranked #7 because of its Google rating and availability: 5.0★ from 776 Google reviews, open 24/7.
Based in Elgin, 18 mi away
Ranked #8 because of its Google rating and availability: 5.0★ from 784 Google reviews, open 24/7.
Based in Elgin, 21 mi away
Ranked #9 because of its Google rating and availability: 5.0★ from 1,021 Google reviews, open 24/7.
Based in Crystal Lake, 15 mi away
Ranked #10 because of its Google rating and availability: 4.9★ from 571 Google reviews, open 24/7.
Based in Crystal Lake, 17 mi away
Ranked #11 because of its Google rating and availability: 4.8★ from 1,043 Google reviews, open 24/7.
Based in McHenry, 17 mi away
Ranked #12 because of its Google rating and availability: 4.9★ from 596 Google reviews, open 24/7.
Based in Hampshire, 12 mi away
Ranked #13 because of its Google rating and availability: 5.0★ from 153 Google reviews, open 24/7.
Based in Crystal Lake, 16 mi away
Ranked #14 because of its Google rating and availability: 4.8★ from 744 Google reviews, open 24/7.
Based in Crystal Lake, 17 mi away
Ranked #15 because of its Google rating and availability: 4.9★ from 472 Google reviews, open 24/7.
Based in Crystal Lake, 15 mi away
Ranked #16 because of its Google rating and availability: 4.8★ from 460 Google reviews, open 24/7.
Based in Huntley, 21 mi away
Ranked #17 because of its Google rating and availability: 4.9★ from 820 Google reviews, open 24/7.
Based in Crystal Lake, 13 mi away
Ranked #18 because of its Google rating and availability: 4.9★ from 147 Google reviews, open 24/7.
Based in Crystal Lake, 15 mi away
Ranked #19 because of its Google rating and availability: 4.8★ from 250 Google reviews, open 24/7.
Based in Crystal Lake, 15 mi away
Ranked #20 because of its Google rating and availability: 5.0★ from 116 Google reviews, open 24/7.
Based in Elgin, 20 mi away
Ranked #21 because of its Google rating and availability: 4.9★ from 351 Google reviews, open 24/7.
Based in Algonquin, 17 mi away
Ranked #22 because of its Google rating and availability: 5.0★ from 148 Google reviews, open 24/7.
Based in Carpentersville, 19 mi away
Ranked #23 because of its Google rating and availability: 4.8★ from 483 Google reviews, open 24/7.
Based in Cary, 19 mi away
Ranked #24 because of its Google rating and availability: 4.9★ from 338 Google reviews, open 24/7.
Based in Elgin, 21 mi away
Ranked #25 because of its Google rating and availability: 4.9★ from 412 Google reviews, open 24/7.
#1 to #25 are shown in full above. Here are #26 to #50, in CR Score order; each links to its profile. We publish the top 50 of 359 ranked HVAC contractors here; the rest are on their profiles.
20 more HVAC contractors within 25 mi that we can't rank yet: too few reviews, or a trade we couldn't confirm. Listed A to Z.
| Business | Google rating | Distance |
|---|---|---|
| A & J General | 5.0★ (2) | 15 mi |
| A Hartlett & Son | 4.5★ (2) | 10 mi |
| Air Man Heating, Cooling & Plumbing (Air Management Services Inc) | In Marengo | |
| Air Management Services Inc | 4.0★ (2) | 12 mi |
| Alex’s Duct Cleaning | 5.0★ (269) | 16 mi |
| Carr's Air Maintenance, Ltd. | In Marengo | |
| Conservative Heating & Air Conditioning | 3.0★ (2) | 17 mi |
| D & D Comfort Inc. Heating & Air Conditioning, Inc. | 4.9★ (110) | 12 mi |
| Dad And Son LLC | 5.0★ (2) | 12 mi |
| Eagle Refrigeration Service | 4.5★ (2) | 19 mi |
| HANDYMAN WE DO IT ALL INC. | 3.7★ (6) | In Marengo |
| Knobloch Plumbing, Inc. | In Marengo | |
| Magic HVAC Inc | 5.0★ (2) | 18 mi |
| Newton's HVAC | 5.0★ (2) | 15 mi |
| Next Level Plumbing | In Marengo | |
| Nick's Action Air | 5.0★ (2) | 15 mi |
| One Call Heating & Cooling | 5.0★ (2) | 12 mi |
| Service Concepts Inc - Commercial Heating and Cooling - Genoa, IL | 3.0★ (2) | 12 mi |
| Zenks Plumbing LLC | In Marengo | |
| ZN Heating and Cooling, Inc | 5.0★ (2) | 14 mi |
National price ranges in USD, not adjusted for Marengo. Each row names its basis and the month we checked it.
| Job | Low | Typical | High | Basis | Checked |
|---|---|---|---|---|---|
| AC replacement | $3,887 | $5,978 | $8,073 | Per system, installed (unit plus labor); typical range of customer-reported jobs. US national range | October 2026 |
| Furnace replacement | $2,823 | $4,814 | $6,896 | Per system, installed; typical range of customer-reported jobs. US national range | October 2026 |
In Illinois, furnace and heat pump calls peak in the coldest winter weeks and AC calls in summer heat waves. Spring and fall are the easiest times to book maintenance or a replacement.
We scored 359 Marengo HVAC contractors on 8 factors, weighted as shown. A business is ranked when its trade is confirmed and it has 3 or more Google reviews or a claimed profile. Unknown factors are left out of the score, not counted as zero. Scores last refreshed October 22, 2026.
Paid placement never changes a rank or score. Featured businesses are paid, labelled, limited to 3 and shown above the ranking, outside it.
| Factor | Weight | Computed from | In Marengo data |
|---|---|---|---|
| Reputation | 35% | Bayesian-adjusted Google star rating | Measured |
| Credentials | 15% | Active state license 0.6, bond 0.2, workers’ comp 0.2 | Not yet collected |
| Review volume | 10% | log10(reviews + 1) against the list maximum | Measured |
| Recency | 10% | Share of reviews from the last 12 months | Not yet collected |
| Availability | 10% | Weekly open hours, Saturday, Sunday, 24/7 or same-day | Measured |
| Trade focus | 10% | Google main category 1.0, business name 0.7, additional category 0.5 | Measured |
| Proximity | 5% | 1.0 when based in the city, falling to 0 at the trade’s radius | Measured |
| Completeness | 5% | Website, photos, description, hours, claimed profile (0.2 each) | Measured |