The article presents the results and discussions of the application of the SERVQUAL model carried out in a company dedicated to the maintenance, installation and repair of air conditioning systems (HVAC) in Metropolitan Lima, Peru; whose objective for which the research is carried out is to identify the dimension that most impacts with respect to quality of service using the SERVQUAL model considering quality of service as the weighted sum of gaps. 91 companies were surveyed with 3 sections for each, the first of them valued the expectations that customers would have, the second the perceptions after receiving the service and in the last they scored the dimension they considered most important. The highest rated dimension or with the smallest gap is the tangible dimension with a gap of -0.35, the most important dimension according to customers is the reliability dimension with an average percentage of 24.3% and the dimension that most negatively influences the service quality index is the reliability dimension with a weighted gap of -15.69.