Verify the business, not only the salesperson
TSSA states that registered fuels contractors are the only businesses legally authorized to perform fuels-related work in Ontario. Use the public registry and confirm the legal name matches the agreement. Ask who will attend, what certifications apply to the task and whether subcontractors perform electrical or other regulated work. Verify insurance and municipal or permit responsibilities as appropriate. Registration is a minimum authorization signal, not an endorsement, so technical quality and business practices still require evaluation.
Look for diagnostic thinking
A strong contractor asks about comfort, energy use, renovations, noise, humidity and equipment history. Replacement proposals should have a sizing basis and consider ducts, returns, electrical capacity, venting, drainage and controls. Repair proposals should explain the operating sequence, tests and evidence leading to the diagnosis. Beware of conclusions reached without inspecting the relevant system. Photographs can document conditions, but measurements and manufacturer data make recommendations more defensible.
Compare written proposals
Obtain model numbers, capacity, efficiency, controls, accessories and all supporting work in writing. Clarify equipment availability and whether substitutions require approval. List permits, inspections, patching, disposal, crane or access work and exclusions. Define how concealed conditions become change orders and who authorizes additional cost. Sales promises about quietness, room comfort or savings should appear in the written scope if they materially influence the purchase. A verbal promise is difficult to audit after installation.
References, reviews and complaints
Recent references for similar housing and equipment are more informative than a generic star average. Ask whether the project stayed within scope, how deficiencies were handled and whether warranty calls were responsive. Read negative reviews for patterns rather than treating every dispute as equal. Confirm the business has a stable service channel and physical operating identity appropriate to the job. Do not assume marketplace badges replace regulatory verification. High-pressure discounts and demands for disproportionate payment before materials or work deserve caution.
Commissioning and aftercare
Put startup testing and homeowner orientation in the agreement. Appropriate commissioning varies by system but can include airflow, static pressure, temperature performance, combustion or refrigerant procedures, drainage, safeties, control staging and noise inspection. Collect permits, model and serial numbers, warranty registration, manuals and baseline settings. Ask who responds if the system meets a thermostat setpoint but fails to solve the documented comfort problem. The relationship after payment is part of the product being purchased.