This study proposes an experimental method for the evaluation of a building's equipment and subsystems through the continuous monitoring of electrical and environmental process variables. The aim of the study is to improve the building's comfort and energy performance using an automatic control system. A case study of a building's air-conditioning system is presented using the proposed method. A dynamic equipment-control model for an artificially conditioned environment is described. Additionally, empirical models are developed that relate equipment variables, the conditioned environment and a building's surroundings and occupation characteristics using representation through transfer functions and auto-regressive models with exogenous inputs (ARX). The empirical models were created using continuous monitoring data via the Internet and a low-cost platform known as the end use monitoring centre (EUMC). These models represent the relevant characteristics of the involved variables in consideration of the complexity of the modelled phenomena. An automatic equipment control system was designed and installed. The systems resulted in significant improvements in comfort and energy efficiency. The proposed method can be applied to diverse types of equipment and subsystems in buildings. (C) 2014 Elsevier B.V. All rights reserved.