Small Business Health Insurance Affordability Act of 2014 - Amends the Internal Revenue Code, with respect to the small employer health care insurance tax credit, to: (1) revise the definition of "eligible small employer" to mean an employer with not more than 50 (currently, 25) full-time employees; (2) increase the employee threshold from 10 to 20 employees for purposes of determining the maximum allowable amount of such credit; (3) eliminate the requirement that employers contribute the same percentage of cost of each employee's health insurance and the cap limiting eligible employer contributions to average premiums paid to a health care exchange; and (4) extend from 2 to 3 consecutive taxable years the period during which an employer may claim such credit. Treats health insurance providing essential health benefits as defined by the Patient Protection and Affordable Care Act through a plan not offered through an exchange as a qualified health plan offered through an exchange.