Look for recommendations from acquaintances and family members to generate a list of potential heating repair companies. Also keep a list of companies they don't recommend so you don't bother calling them during your search.
Contact at least three heating repair companies. Most charge a fee for coming to your home to look at the furnace so having multiple companies come out isn't a feasible option for most homeowners. A prescreening phone call to the companies helps you narrow down the possibilities.
Request a copy of the license and credentials for the heating repair specialist. A license is one important factor in ensuring the repairman knows what he is doing when it comes to your heating system.
Ask about the company's insurance policies. Request proof of insurance before you hire a heating specialist. Insurance is another essential component to ensure you are covered if the heating specialist messes up or gets hurt on your property. Look for both liability and workers comp insurance.
Determine how long the company has been in business. Check with the Better Business Bureau for any complaints against the company. A long history free of complaints is a good sign.
Ask if the company guarantees their work. A company that backs up their work is a good sign. You don't want to get stuck calling someone else to fix a mistake made by the original repairman.
Request a list of references from the heating repair specialist. Contact several of the references to determine their level of satisfaction, the timelessness and the quality of work performed.
Ask about their normal hourly charge for service calls. Also check on the after hours and weekend availability and charges. Most companies should have standard hourly rate for work.
Compare all of the factors to choose the best heating repair specialist. Trust your gut when comparing the different qualifications.