We investigate the locality of electronic interactions in aluminum as a function of smearing/electronic temperature in the context of O(N) Density Functional Theory calculations. Specifically, we determine the convergence in energy and atomic forces with truncation region size for smearing of 0.001-0.15 Ha. We find exponential convergence accompanied by a rate that increases sub-linearly with smearing, with truncation region sizes of 48-64 Bohr required to achieve chemical accuracy for typical smearing values of 0.001-0.01 Ha. This translates to O(N) scaling for systems larger than O(1000) atoms. (C) 2017 Elsevier B.V. All rights reserved.