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Emergency HVAC Contractors in Harvard, IL (2026)

Top 50 of 225 HVAC contractors, in emergency orderUpdated 0 paid placements in this rankingHow we rank

25 of the 50 HVAC contractors on this list post 24/7 hours. 24/7 businesses come first, then same-day, each ranked by CR Score with availability weighted higher.

If you smell gas, leave the building now and call your gas utility or 911 from outside.

The short answer

  1. 1

    #1 for emergency heating and cooling in Harvard: Black Diamond Plumbing & Mechanical Inc., open 24/7.

Rankings can't be bought. Contractors can't pay to change their rank or score. How we rank

Top emergency HVAC contractors in Harvard at a glance

Top emergency HVAC contractors in Harvard at a glance
RankBusinessCR ScoreGoogle ratingBased inHours
1Black Diamond Plumbing & Mechanical Inc.644.9★ (6,580)McHenry, 18 mi away24/7
2Woodstock Heating, Cooling & Electrical634.9★ (1,222)Woodstock, 11 mi away24/7
3GSHA Services, LTD624.9★ (747)Woodstock, 13 mi away24/7
4Master Services Inc.614.7★ (976)Lake Geneva, 15 mi away24/7
524HR Home Comfort Services604.9★ (1,374)Lake in the Hills, 23 mi away24/7
6McHenry Heating & Air, Inc.604.9★ (596)McHenry, 19 mi away24/7
7H. J. Faust, Inc. Heating and Air Conditioning604.9★ (1,340)Burlington, 24 mi away24/7
8Althoff Home Services604.8★ (1,043)Crystal Lake, 22 mi away24/7
9WeatherWise Heating & AC repair604.8★ (744)Crystal Lake, 20 mi away24/7
10Legacy Home Services604.9★ (571)Crystal Lake, 20 mi away24/7

Call an emergency HVAC contractor in Harvard now

24/7 hours mean the business says its phone is answered around the clock. Arrival time depends on where the crew is. Ask for an arrival window when you call.

The 50 emergency HVAC contractors in Harvard, ranked

24/7 first, then same-day service, then the rest. Each group is in CR Score order on emergency weights. The full ranking of all 225 is on the HVAC contractors page.

Scores below: based on 8 of 10 factors; credentials and recency not yet collected. Hatched segments mark factors we don't have yet.

  3. #3 GSHA Services, LTD

    Based in Woodstock, 13 mi away

    62/100CR Score

    Ranked #3 because of its Google rating and trade focus: 4.9★ from 747 Google reviews, listed on Google as “HVAC contractor”.

    • 4.9★ from 747 Google reviews
    • Open 24/7
    Hours
    Open 24 hours, 7 days
    Address
    1257 Cobblestone Way Unit A, Woodstock, IL 60098
    View profile for GSHA Services, LTD(224) 220-3660

  4. #4 Master Services Inc.

    Based in Lake Geneva, 15 mi away

    61/100CR Score

    Ranked #4 because of its Google rating and trade focus: 4.7★ from 976 Google reviews, listed on Google as “HVAC contractor”.

    • 4.7★ from 976 Google reviews
    • Open 24/7
    Hours
    Open 24 hours, 7 days
    Address
    N3481 Co Trunk H, Lake Geneva, WI 53147
    View profile for Master Services Inc.(262) 244-5650

  8. #8 Althoff Home Services

    Based in Crystal Lake, 22 mi away

    60/100CR Score

    Ranked #8 because of its Google rating and trade focus: 4.8★ from 1,043 Google reviews, listed on Google as “HVAC contractor”.

    • 4.8★ from 1,043 Google reviews
    • Open 24/7
    Hours
    Open 24 hours, 7 days
    Address
    8001 S Illinois Rte 31, Crystal Lake, IL 60014
    View profile for Althoff Home Services(815) 455-7000

  10. #10 Legacy Home Services

    Based in Crystal Lake, 20 mi away

    60/100CR Score

    Ranked #10 because of its Google rating and trade focus: 4.9★ from 571 Google reviews, listed on Google as “HVAC contractor”.

    • 4.9★ from 571 Google reviews
    • Open 24/7
    Hours
    Open 24 hours, 7 days
    Address
    7316 Teckler Blvd Ste 2B, Crystal Lake, IL 60014
    View profile for Legacy Home Services(815) 938-0137

  12. #12 Air Systems, Inc.

    Based in Elkhorn, 16 mi away

    60/100CR Score

    Ranked #12 because of its Google rating and trade focus: 4.8★ from 277 Google reviews, listed on Google as “HVAC contractor”.

    • 4.8★ from 277 Google reviews
    • Open 24/7
    Hours
    Open 24 hours, 7 days
    Address
    4520 Co Hwy F, Elkhorn, WI 53121
    View profile for Air Systems, Inc.(262) 728-1655

  20. #20 Absolute Comfort

    Based in Crystal Lake, 19 mi away

    59/100CR Score

    Ranked #20 because of its Google rating and trade focus: 4.8★ from 250 Google reviews, listed on Google as “HVAC contractor”.

    • 4.8★ from 250 Google reviews
    • Open 24/7
    Hours
    Open 24 hours, 7 days
    Address
    60 W Terra Cotta Ave, Crystal Lake, IL 60014
    View profile for Absolute Comfort(815) 893-9276

Top 50 of 225 HVAC contractors by emergency score

#1 to #25 are shown in full above. Here are #26 to #50, in CR Score order; each links to its profile.

HVAC contractors in Harvard, ranks 26 to 50
RankBusinessCR ScoreGoogle ratingDistance
26Com24 Heating & Air Conditioning LLC584.9★ (338)25 mi
27McNally's Heating and Cooling585.0★ (116)21 mi
28Bear Necessities Home Services585.0★ (174)24 mi
29Arctic Heating & Cooling574.9★ (102)20 mi
30CKA Mechanical Inc.575.0★ (153)23 mi
31Air Blue Heating and Cooling575.0★ (148)24 mi
32Everything Mechanical Heating and Cooling574.7★ (69)16 mi
33Half Price Heating & Air574.7★ (75)17 mi
34D & D Comfort Inc. Heating & Air Conditioning, Inc.574.9★ (110)21 mi
35Dowe & Wagner Inc. Powered by Legacy Home Services574.4★ (107)16 mi
36Wally's Heating & AC574.9★ (95)21 mi
37Northern Continental Heating & Cooling, Inc.574.8★ (125)22 mi
38Broadway Heating and Cooling LLC575.0★ (33)16 mi
39Hudak Heating & Air Conditioning575.0★ (16)12 mi
40American Comfort Central574.8★ (50)18 mi
41C&C Heating & Air Conditioning574.7★ (28)14 mi
42Duane Blanton Plumbing, Sewer, Heating & Cooling574.9★ (105)23 mi
43Alex Quality Services575.0★ (101)24 mi
44South Shore Heating & Air Conditioning Inc.575.0★ (104)25 mi
45Absolute Value Heating & Cooling - Rockford564.9★ (85)23 mi
46Evolution Mechanical Heating & Cooling565.0★ (57)21 mi
47Woodstock Heating and Cooling, LLC565.0★ (45)20 mi
48Algonquin Heating & Air Conditioning564.7★ (143)24 mi
49Andrews heating and air inc564.9★ (36)19 mi
50American Heating & Cooling564.7★ (28)16 mi

How we ranked emergency HVAC contractors in Harvard

Emergency lists move 10 points of the CR Score from reputation to availability: 15% and 15%. Availability credits 24/7 hours, same-day service, weekend hours and weekly open hours. 24/7 HVAC contractors are listed first, then same-day, then the rest; ranks follow that order. Paid placement never changes a rank.

Paid placement never changes a rank or score. Featured businesses are paid, labelled, limited to 3 and shown above the ranking, outside it.

Read the full method: formula, sources and exclusions

CR Score factors and weights
FactorWeightComputed from
Reputation15%Google star rating, adjusted for how many reviews back it
Credentials15%Active state license, bond and workers’ comp on file
Review volume10%Number of Google reviews, compared with the most-reviewed business on the list
Recency5%Share of reviews from the last 12 months
Availability15%Weekly open hours, Saturday, Sunday, 24/7 or same-day
Trade focus10%How clearly the business does this trade (its Google category and name)
Proximity5%Based in the city scores highest, less the farther away it is
Claimed profile10%The business has claimed its ContractorsRanked profile (free or paid earn the same)
Partnered5%The business links to ContractorsRanked from its own website with our badge, checked periodically
ContractorsRanked reviews10%Verified customer reviews collected by ContractorsRanked: their rating and how many there are

Emergency HVAC contractors in Harvard: questions

Which HVAC contractors in Harvard are open 24/7?

25 on this list post 24/7 hours, including Black Diamond Plumbing & Mechanical Inc., Woodstock Heating, Cooling & Electrical, GSHA Services, LTD, Master Services Inc. and 24HR Home Comfort Services.

Who is ranked #1 for emergency heating and cooling in Harvard, IL?

Black Diamond Plumbing & Mechanical Inc. is #1, with a CR Score of 64 out of 100 on emergency weights.

How are emergency HVAC contractors in Harvard ranked?

Emergency lists move 10 points of the CR Score from reputation to availability: 15% and 15%. Availability credits 24/7 hours, same-day service, weekend hours and weekly open hours. 24/7 HVAC contractors are listed first, then same-day, then the rest; ranks follow that order. Paid placement never changes a rank.

What should I do before the HVAC contractor arrives?

If you smell gas, leave the building now and call your gas utility or 911 from outside.

How many emergency HVAC contractors here list a phone number?

25 of the 25 businesses ranked in full list a phone number. Tap Call to dial it.

Update log for Harvard

  1. October 2026: CR Scores recalculated for 225 hvac contractors serving Harvard.
  2. October 2026: 5 duplicate listings merged.

More emergency and heating and cooling pages