| 35099 | United States | OneWorld Sustainable Inc. | 609 Church Street, Vidalia, Georgia 30474 | +1 770 4902585 | oneworldsustainable.com | | |
| 35100 | United States | OnForce Solar | 728 E. 136th St., Bronx, NY 10454 | +1 800 7864028 | www.onforcesolar.com | | |
| 35071 | United States | Old Dominion Solar, llc | 254 S Cole Rd., Boise, Idaho, 83709 | +1 208 8773777 | www.olddominionepc.com | | |
| 35072 | United States | Olde Towne Heating & Air | 443F, Long Point Rd., Mount Pleasant, SC, 29464-8212 | +1 843 4850967 | https://www.oldetowneheatingandair.com | | |
| 35073 | United States | Olivas Roofing and Solar | San Angelo, TX, 76905 | +1 737 6103042 | https://www.olivasroofingandsolar.com | | |
| 35074 | United States | Oliver Heating & Cooling | 101, Waverly Ave, Morton, PA, 19070 | +1 877 7428251 | https://www.oliverheatcool.com | | |
| 35075 | United States | Olson Electric Service Inc. | Dallas, Texas | +1 972 7094999 | https://www.olsonelectricservice.com | | |
| 35076 | United States | Olson Solar Energy | 1009 Riders Club Rd., Suite B, Onalaska WI, 54650 | +1 608 7802347 | https://www.olsonsolarenergy.com | | |
| 35077 | United States | Olsson Roofing Company | 740 South Lake St., PO Box 1450 Aurora, IL 60507 | +1 630 8920449 | www.olssonroofing.com | | |
| 35078 | United States | Oltmans Construction Co. | 10005, Mission Mill Road, Whittier, CA, 90601 | +1 562 9484242 | www.oltmans.com | | |
| 35079 | United States | Olympus Home | 2514, River Road, Powderville, South Carolina, 29673 | +1 864 6194944 | olympushome.org/ | | |
| 35080 | United States | Olympus Solar Inc. | 3817 N Oracle Rd. Suite B, Tucson, AZ 85705 | +1 520 6618556 | https://olympussolarinc.com | | |
| 35081 | United States | Omega Home Remodeling Inc. | 18115 Valley View Ave, Ste 205, Cerritos CA 90703 | +1 888 6634260 | www.omegahomeremodeling.com | | |
| 35082 | United States | Omni Electric | 720 7th Street, New Kensington, PA 15068 | +1 724 2241943 | omnielectricpa.com | | |
| 35083 | United States | Omni Energy LLC | | | energyomni.com | | |
| 35084 | United States | Omni Energy Solutions | Sonoma, California | | https://www.omnienergysolution.com | OutBack Power, SMA Solar Technology AG, Schneider Electric SA | |
| 35085 | United States | Omni Solar Solutions, LLC | | | www.omnisolarcorp.com | | |
| 35086 | United States | Omnibuild General Contractors | 4243, Floyd Hwy N, Bay A, Floyd, VA, 24091 | +1 540 7452599 | https://omnibuildconstruction.com | | |
| 35087 | United States | On The Road Again RV | 23602 N. 35th Drive Glendale, AZ 85310 | +1 602 2967549 | https://www.azrvservices.com | | |
| 35088 | United States | On Time Electric | | +1 360 4599341 | https://on-time-electric.business.site | | |
| 35089 | United States | One Love Solar | 2068 Norloti St., Palm Springs, CA 92262-4036 | +1 760 2191832 | www.onelovesolar.com | | |
| 35090 | United States | One Planet Solar & Wind Inc. | 2068 Highway 171, Suite 2, Stonewall, LA 71078 | +1 318 9259884 | oneplanetsolar.com | Fronius International GmbH, Enphase Energy, Inc. | |
| 35091 | United States | ONE Service Pros | 319 Blue Peacock Way, Suite 2, Seymour, TN 37865 | +1 865 3510241 | www.oneservicepros.com | | |
| 35092 | United States | One Solar Utah LLC | 2391 S 1560 W, Woods Cross, UT 84087 | +1 801 3178444 | https://www.1solar.com | Altenergy Power System Inc. | |
| 35093 | United States | One Source Roofing | 515 18th Street, Orlando, FL 32805 | +1 407 6608552 | www.onesourceroofing.net | | |
| 35094 | United States | One Way Electric | 3820 W Happy Valley Rd Ste 141-462, Glendale, AZ 85310 | +1 623 5829420 | www.onewayelectric.com | | |
| 35095 | United States | One-Up Solar Contractor, Inc. | | +1 786 7200592 | www.one-upsolar.com | | |
| 35096 | United States | One80 Solar Group LLC | 216 N. Mosley St., Wichita, KS 67202 | +1 316 2533929 | www.one80solar.com | | |
| 35097 | United States | OneSolar | 3202 Sparkling Drive, Sebring, FL 33870 | +1 863 3821000 | www.onesolar.com | | |
| 35098 | United States | OneTwoRoof | 17252 Hawthorne Blvd, #285, CA 90504 | +1 424 3410954 | www.onetworoof.com | | |