#1
Zark Heating & Cooling Inc.
“My furnace control panel went out and needed to be replaced. The technician was very knowledgeable, kind and efficient. I will definitely use Zark again, when needed.” — Google review
Experts Reviews · 2026 Ratings
The Best Boiler Installers in Joliet, IL
We graded 10 companies on seven things customers actually report: satisfaction, reliability, workmanship, value, momentum, track record and how owners handle complaints.
$228typical jobMedian of the bill customers reported in their Google review (Google asks reviewers for a price range; we use the middle of each range).
98%say the price was fairOf customers who rated the price, the share who chose “Great price” or “Reasonable” rather than “Overpriced”.
4.92★average ratingPlain average of every Google star rating we collected for these companies.
1.3%bad jobs (1–2★, 2 yrs)Share of 1–2★ reviews in the last 24 months — or the 20 newest reviews when the company had fewer than 20 in that time.
From 7,718 Google reviews of 10 top-rated boiler installers nationwide; 10 of them in Joliet, IL. Updated November 11, 2026.
Find the right company for your job
Pick the job — we re-rank companies by how customers rated that exact job.
Overall ratings
Experts Score 0–100Experts Score (0–100)Absolute quality first: recency-weighted star average (≈54%), share of 1–2★ reviews (≈24%), customers’ price verdicts (≈14%), owner replies to critical reviews (≈7%); minus up to 10 points each for complaints flagged in Google review highlights and for a real slide in recent ratings. Hover a company’s score on its page for the full breakdown. and a letter grade per factor (A = top 20% of boiler installers).
| # | Company | ScoreExperts Score (0–100)Absolute quality first: recency-weighted star average (≈54%), share of 1–2★ reviews (≈24%), customers’ price verdicts (≈14%), owner replies to critical reviews (≈7%); minus up to 10 points each for complaints flagged in Google review highlights and for a real slide in recent ratings. Hover a company’s score on its page for the full breakdown. | FactorsFactor grades, in orderSatisfaction (54%): Recency-weighted star average (2-year half-life), shrunk toward the category mean by review volume; the company’s own lifetime average as the prior; absolute: 4.0★ = 0, 5★ = 100.Reliability (24%): How rarely jobs go badly: share of 1–2★ reviews — 60% the last 24 months (or the 20 newest if fewer), 40% all-time; 0% = 100, 15%+ = 0; the category percentile can only raise it.Craft & service (0%): Google review highlights: Quality, Professionalism, Responsiveness, Punctuality — how rarely reviewers flag them as a negative, per review since highlights began; 0% = 100, 5%+ = 0. Subtracted from the score (up to −10), never averaged in — clean highlights are the norm, not a bonus.Value (14%): Customers’ own price verdicts (Great / Reasonable vs Overpriced) and Value highlights; 65% absolute (all “reasonable” ≈ 80, “great” = 100), the category percentile can only raise it.Momentum (0%): Penalises only a real slide: last-12-month average below lifetime (−0.5★ = 0). Still 4.8★+ over the last year, or steady/improving = 100. Subtracted from the score (up to −10), never averaged in.Replies to reviews (7%): How often the owner publicly replies to reviews under 5★ (1–4★). Needs 3+ such reviews, otherwise not counted; 65% absolute (80%+ replied = 100), the category percentile can only raise it.One letter per factor score: A = 80+, B = 60–79, C = 40–59, D = 20–39, F = below 20. | ★Google star rating as shown on Google Maps. | Typical billMedian bill customers of this company reported in their reviews (needs 3+ priced reviews). |
|---|---|---|---|---|---|
| 1 |  Windy City HVAC RepairJoliet, IL | A 99How the Experts Score is calculatedEach factor is scored 0–100 on absolute terms (standing in the category can only raise it), then weighted; problems flagged in review highlights or a recent slide in ratings are subtracted:Satisfaction 59%99+58.1Reliability 26%99+25.8Value 15%100+15.2Experts Score= 99Not enough data for replies to reviews; its weight is shared by the others.Grade A: A = 80+, B = 60–79, C = 40–59, D = 20–39. Needs 10+ reviews. | AA–AA– | 4.99 | $166 |
| 2 | Zark Heating & Cooling Inc.Joliet, IL | A 97How the Experts Score is calculatedEach factor is scored 0–100 on absolute terms (standing in the category can only raise it), then weighted; problems flagged in review highlights or a recent slide in ratings are subtracted:Satisfaction 55%97+52.9Reliability 24%96+23.3Value 14%100+14.1Replies to reviews 7%100+7.1Experts Score= 97Grade A: A = 80+, B = 60–79, C = 40–59, D = 20–39. Needs 10+ reviews. | AAAAAA | 4.97 | $227 |
| 3 |  Rousculp's Heating and CoolingJoliet, IL | A 96How the Experts Score is calculatedEach factor is scored 0–100 on absolute terms (standing in the category can only raise it), then weighted; problems flagged in review highlights or a recent slide in ratings are subtracted:Satisfaction 55%99+54Reliability 24%99+24Value 14%100+14.1Replies to reviews 7%58+4.1Experts Score= 96Grade A: A = 80+, B = 60–79, C = 40–59, D = 20–39. Needs 10+ reviews. | AAAAAC | 4.98 | $161 |
| 4 |  Comfort Zone ServiceJoliet, IL | A 96How the Experts Score is calculatedEach factor is scored 0–100 on absolute terms (standing in the category can only raise it), then weighted; problems flagged in review highlights or a recent slide in ratings are subtracted:Satisfaction 55%95+51.8Reliability 24%93+22.5Value 14%100+14.1Replies to reviews 7%100+7.1Experts Score= 96Grade A: A = 80+, B = 60–79, C = 40–59, D = 20–39. Needs 10+ reviews. | AAAAAA | 4.96 | $248 |
| 5 |  Service Express Heating and Air ConditioningJoliet, IL | A 96How the Experts Score is calculatedEach factor is scored 0–100 on absolute terms (standing in the category can only raise it), then weighted; problems flagged in review highlights or a recent slide in ratings are subtracted:Satisfaction 55%95+51.8Reliability 24%94+22.8Value 14%100+14.1Replies to reviews 7%100+7.1Experts Score= 96Grade A: A = 80+, B = 60–79, C = 40–59, D = 20–39. Needs 10+ reviews. | AAAAAA | 4.94 | $228 |
| 6 |  Deljo Heating, Cooling & PlumbingJoliet, IL | A 95How the Experts Score is calculatedEach factor is scored 0–100 on absolute terms (standing in the category can only raise it), then weighted; problems flagged in review highlights or a recent slide in ratings are subtracted:Satisfaction 55%95+51.8Reliability 24%97+23.5Value 14%88+12.4Replies to reviews 7%100+7.1Experts Score= 95Grade A: A = 80+, B = 60–79, C = 40–59, D = 20–39. Needs 10+ reviews. | AA–AAA | 4.95 | $383 |
| 7 |  Maertin Heating & CoolingJoliet, IL | A 93How the Experts Score is calculatedEach factor is scored 0–100 on absolute terms (standing in the category can only raise it), then weighted; problems flagged in review highlights or a recent slide in ratings are subtracted:Satisfaction 55%96+52.4Reliability 24%94+22.8Value 14%100+14.1Replies to reviews 7%58+4.1Experts Score= 93Grade A: A = 80+, B = 60–79, C = 40–59, D = 20–39. Needs 10+ reviews. | AAAAAC | 4.98 | $423 |
| 8 |  Service 1 Plumbing, Heating & A/C, Inc.Joliet, IL | A 91How the Experts Score is calculatedEach factor is scored 0–100 on absolute terms (standing in the category can only raise it), then weighted; problems flagged in review highlights or a recent slide in ratings are subtracted:Satisfaction 55%92+50.2Reliability 24%91+22.1Value 14%100+14.1Replies to reviews 7%67+4.7Craft & service penalty98−0.2Experts Score= 91Grade A: A = 80+, B = 60–79, C = 40–59, D = 20–39. Needs 10+ reviews. | AAAAAB | 4.90 | $283 |
| 9 |  Energy Services Air Conditioning & Heating Co. & ElectricalJoliet, IL | A 85How the Experts Score is calculatedEach factor is scored 0–100 on absolute terms (standing in the category can only raise it), then weighted; problems flagged in review highlights or a recent slide in ratings are subtracted:Satisfaction 55%86+46.9Reliability 24%85+20.6Value 14%97+13.7Replies to reviews 7%59+4.2Craft & service penalty99−0.1Experts Score= 85Grade A: A = 80+, B = 60–79, C = 40–59, D = 20–39. Needs 10+ reviews. | AAAAAC | 4.89 | $166 |
| 10 |  Omega Plumbing Heating and CoolingJoliet, IL | A 85How the Experts Score is calculatedEach factor is scored 0–100 on absolute terms (standing in the category can only raise it), then weighted; problems flagged in review highlights or a recent slide in ratings are subtracted:Satisfaction 55%89+48.5Reliability 24%85+20.6Value 14%89+12.6Replies to reviews 7%60+4.2Craft & service penalty87−1.3Experts Score= 85Grade A: A = 80+, B = 60–79, C = 40–59, D = 20–39. Needs 10+ reviews. | AAAAAB | 4.87 | $383 |
What jobs cost
What customers paid, from the price Google asks reviewers to report.
| Job | Low25th percentile: 1 in 4 customers paid less than this. | TypicalMedian of the bill customers reported in their Google review (Google asks reviewers for a price range; we use the middle of each range). | High75th percentile: 1 in 4 customers paid more than this. | FairOf customers who rated the price, the share who chose “Great price” or “Reasonable” rather than “Overpriced”. |
|---|---|---|---|---|
| HVAC system maintenance | $37 | $124 | $264 | 99% |
| A/C system maintenance | $39 | $166 | $318 | 99% |
| HVAC system repair | $145 | $325 | $618 | 98% |
| Heating system maintenance | $37 | $161 | $317 | 98% |
| Heating system installation | $1.4k | $2.1k | $2.8k | 99% |
| Heating system repair | $78 | $192 | $745 | 98% |
| A/C system repair | $216 | $322 | $611 | 98% |
| Install AC | $1.6k | $2.4k | $3.2k | 100% |
| Cleaning | $135 | $198 | $484 | 100% |
| Plumbing pipe repair | $251 | $399 | $480 | 94% |
| Toilet repair | $246 | $340 | $496 | 97% |
| Water heater installation | $1.1k | $1.4k | $2.1k | 100% |
Boiler Installers in Joliet, IL at a glance
How the 10 boiler installers we rated in Joliet, IL compare, and what customers praise most.
Experts Score grades
A = score 80+, F = below 20.
- Grade A10100%
- Grade B00%
- Grade C00%
- Grade D00%
- Grade F00%
Google ratings
Average stars per company.
- 4.90★ and up880%
- 4.80–4.89★220%
- 4.60–4.79★00%
- Below 4.60★00%
What customers praise
Share of Google review highlights.
- Quality1,32320%
- Professionalism1,50923%
- Responsiveness1,36921%
- Punctuality1,32920%
- Value1,04916%
Was the price fair?
All price verdicts left with reviews.
- Great price52829%
- Reasonable1,15363%
- Overpriced332%
- Not sure1136%
Price verdicts by year
Share calling it great / reasonable / overpriced.
2025
2026
How we grade
Satisfaction (54%) — Recency-weighted star average (2-year half-life), shrunk toward the category mean by review volume; the company’s own lifetime average as the prior; absolute: 4.0★ = 0, 5★ = 100.
Reliability (24%) — How rarely jobs go badly: share of 1–2★ reviews — 60% the last 24 months (or the 20 newest if fewer), 40% all-time; 0% = 100, 15%+ = 0; the category percentile can only raise it.
Craft & service (penalty, up to −10) — Google review highlights: Quality, Professionalism, Responsiveness, Punctuality — how rarely reviewers flag them as a negative, per review since highlights began; 0% = 100, 5%+ = 0. Subtracted from the score (up to −10), never averaged in — clean highlights are the norm, not a bonus.
Value (14%) — Customers’ own price verdicts (Great / Reasonable vs Overpriced) and Value highlights; 65% absolute (all “reasonable” ≈ 80, “great” = 100), the category percentile can only raise it.
Momentum (penalty, up to −10) — Penalises only a real slide: last-12-month average below lifetime (−0.5★ = 0). Still 4.8★+ over the last year, or steady/improving = 100. Subtracted from the score (up to −10), never averaged in.
Replies to reviews (7%) — How often the owner publicly replies to reviews under 5★ (1–4★). Needs 3+ such reviews, otherwise not counted; 65% absolute (80%+ replied = 100), the category percentile can only raise it.
The 10 best-rated boiler installers in Joliet, IL average 5.0★ on Google across 7,719 reviews. Zark Heating & Cooling Inc. has the top rating (5.0★), and Energy Services Air Conditioning & Heating Co. & Electrical has the most reviews (2,355). Updated November 11, 2026.
10 companies that meet our bar: rated 4.5★ or higher on Google, with a meaningful review history (7,719 reviews combined) and currently operating. Request a call back and the company will phone you directly.
#2
Deljo Heating, Cooling & Plumbing
“Plumbing repair on previously installed kitchen faucet. Scheduling was somewhat problematic, but work was done at no charge. Justin is an excellent technician and kept me updated on appointments and progress in…” — Google review
#3
Rousculp's Heating and Cooling
“Rousculp’s Heating & Cooling is an amazing company! Todd Rousculp, Isaiah Rivera and Matthew Masson were outstanding! These guys were professional, knowledgeable, very nice guys who knew exactly what they were…” — Google review
#4
Comfort Zone Service
“Josh explained everything very well. It's unfortunate that I had no idea the amount of work that's involved in such a project. I'll keep saving my pennies and who knows, I may call you back. Thanks for coming out.” — Google review
#5
Maertin Heating & Cooling
“Everyone is very professional. They gave us several choices to choose from for both the AC and Furnace. We added an air scrubber which is amazing. They explained all the options and once it was installed they made…” — Google review
#6
Energy Services Air Conditioning & Heating Co. & Electrical
“Caprell from Energy Services is an exceptional technician. He is professional, knowledgeable, kind and most importantly honest. I recommend Energy Services with a high recommendation of Caprell and Leo. It can be…” — Google review
#7
Service 1 Plumbing, Heating & A/C, Inc.
“Had 3 new toilets installed by Al and Nate. Very happy that we chose this company! So easy from scheduling to the final install. The technicians were great!” — Google review
#8
Service Express Heating and Air Conditioning
“Rudi was here for a pre-winter tuneup of my furnace. When I asked him what was involved in a tuneup, he took the time to explain all the things he was going to check out or adjust on the furnace. I believe he did a…” — Google review
#9
Omega Plumbing Heating and Cooling
“I had Bill come to my house today and he was awesome. Thought I needed something done, but really didn't. He explained to me what is and isn't necessary - all around professional and very honest individual. Will…” — Google review
#10
Windy City HVAC Repair
“Bobby was super kind and got the job done efficiently! He even waited outside for 20 minutes when I hadn’t heard my phone! Thank you again” — Google review
How we pick boiler installers in Joliet
We scan Google Maps for boiler installer listings in and around Joliet, keep only open businesses whose main category matches the service, and require a Google rating of at least 4.5 from at least 20 reviews. Companies are ordered by a confidence-weighted score that balances rating and review volume. We do not accept payment for placement.
Frequently asked questions
Who is the highest-rated boiler installer in Joliet?
Zark Heating & Cooling Inc. has the highest Google rating on our Joliet list: 5.0 out of 5 from 891 reviews (as of November 11, 2026).
Which boiler installer in Joliet has the most reviews?
Energy Services Air Conditioning & Heating Co. & Electrical has the most Google reviews among the companies listed here: 2,355, with a 4.9★ average.
How are these boiler installers chosen?
Only open Joliet-area businesses whose Google category matches the service, rated at least 4.5★ from at least 20 Google reviews. They are ordered by a confidence-weighted score of rating and review volume. Placement is never paid.
Also in Joliet: Movers · Nutritionists · Wallpaper Removal Services · Gutter Cleaning