Heating, ventilation, and air conditioning companies represent one of the more commonly sold types of service businesses throughout Durham and the Triangle, reflecting both the steady demand for these services, since heating and cooling systems require ongoing maintenance and eventual replacement regardless of broader economic conditions, and the relatively fragmented nature of this industry, where many companies are owned by individuals who eventually look toward retirement or other transitions after years of building a service area and customer base. Buyers evaluating an HVAC company often look closely at the mix between installation work and ongoing maintenance contracts, since maintenance agreements represent the kind of recurring revenue discussed elsewhere, along with the condition of the company's vehicle fleet and equipment, and how certifications and licenses required to operate are held. For owners of HVAC businesses throughout the region considering a sale, understanding how these industry specific factors are likely to be evaluated helps in preparing the business and setting realistic expectations.