Telehealth has great potential to improve access to care but its adoption in routine health care has been slow. The lack of clarity about the value of telehealth implementations has been one reason cited for this slow adoption. The Center for Information Technology Leadership has examined the value of telehealth encounters in which there is a provider both with the patient and at a distance from the patient. We considered three models of telehealth: store-and-forward, real-time video and hybrid systems. Evidence from the literature was extrapolated using a simulation, which found that the hybrid model was the most cost-effective of the three. The simulation predicted savings of $4.3 billion per year if hybrid telehealth systems were to be implemented in emergency rooms, prisons, nursing home facilities and physician offices across the US. We also conducted a sensitivity analysis to determine which factors most affected costs and savings. For all three telehealth models, the highest sensitivities were to the cost of a face-to-face visit, the cost of a telehealth visit and the success rate of a telehealth visit, i.e. the proportion of telehealth visits that avoided the need for a face-to-face visit. Payers, providers and policy-makers should work together to remove the barriers to the adoption of telehealth in order to make it widely available to all.