| Business | Phone |
| Grace Mechanical 44 Elson St, Markham L3S 2J4 | (905) 471-8280 |
| Home Air System 7725 Birchmount Rd, Markham L3R 9X3 | (905) 415-2226 |
| Lakeside Air Systems Inc 250 Cochrane Dr, Markham L3R 8E5 | (905) 479-1182 |
| Mayfair Systems 155 Mcintosh Dr, Markham L3R 0N6 | (905) 475-6635 |
| Neotech Mechanical Inc 230 Don Park Rd, Markham L3R 2P7 | (905) 475-2200 |
| Nortown Natural Gas Ltd 11 Mary Elizabeth Cres, Markham L3R 9M2 | (905) 470-2478 |
| Scarborough Heating & Air Cond 19 Eastwood Cres, Markham L3P 5Z6 | (905) 294-8060 |
| Sig Mechanical Svc Ltd 51 Esna Park Dr #B, Markham L3R 1C9 | (905) 475-3000 |
| Tri Air Systems 251 Amber St #6, Markham L3R 3J7 | (416) 293-1801 |
| Davenport-Campbell Co Ltd 151 Bentley St #1, Markham L3R 3X9 | (905) 841-2314 |
| Dellwood Heating & Air Cond 15 Heritage Rd, Markham L3P 3T1 | (905) 294-5116 |
| Domilco Limited 9366 Kennedy Rd, Markham L6C 1N6 | (905) 477-1734 |
| Dual Heating & Mech Contrs Ltd 105 Gibson Dr, Markham L3R 3K7 | (905) 479-3233 |