Our study looked at the extent to which firm characteristics such as total firm capital affect electricity saving in energy-intensive industry in Sweden from 2007 to 2015. Specifically, the most influential variables for systematic variation in electricity saving in the energy-intensive companies participating in Sweden's voluntary programme for improving energy efficiency in energy-intensive industry (the PFE) were studied by analysing monetary investment, payback time and firm characteristics. Monetary investment and payback time influenced electricity savings during the PFE more than firm characteristics, with monetary investment being most influential. Nevertheless, the total systematic variation in firm characteristics may account for similar to 16% of the systematic variation in electricity saving, where similar to 74% (32 of 43) of the studied firm characteristics seemed to merit further investigation and where similar to 49% (21 of 43) of firm characteristics appeared most influential. The most influential firm characteristics were total rum capital, stock turnover ratio, machinery, short-term liabilities per turnover ratio and goodwill. The overall results showed that firm characteristics can influence a firm's energy-saving activities and indicated a tendency for more energy savings in companies that were financially weaker or had done less work to improve energy efficiency prior to the PFE.