Deep neural networks (DNNs) are state-of-the-art models adopted in many machine learning based systems and algorithms. However, a notable issue of DNNs is their considerable energy consumption for training and inference. At the hardware level, one current energy-saving solution at the inference phase is to reduce the voltage supplied to the DNN hardware accelerator. However, operating in the low-voltage regime would induce random bit errors saved in the memory and thereby degrade the model performance. To address this challenge, we propose , a novel input transformation technique as an add-on module, to protect the model from severe accuracy drops in low-voltage regimes. With NeuralFuse, we can mitigate the tradeoff between energy and accuracy without retraining the model, and it can be readily applied to DNNs with limited access, such as DNNs on non-configurable hardware or remote access to cloud-based APIs. Compared with unprotected DNNs, our experimental results show that NeuralFuse can reduce memory access energy up to 24% and simultaneously improve the accuracy in low-voltage regimes up to an increase of 57%. To the best of our knowledge, this is the first model-agnostic approach (i.e., no model retraining) to mitigate the accuracy-energy tradeoff in low-voltage regimes.