A grueling hunt for quality appliances inspired three homeowners with young children to find a better way. In 2008, they launched Designer Appliances. The company blends online and offline elements to offer more information, wider product selection and greater convenience to its customers. The blend has evolved as tax laws and manufacturer requirements change. This fall, the company opened a showroom in Montclair. It hopes to begin staking out a national presence over the next two years.