In addition to efficiency, what other aspect is improved by using properly tuned gas appliances?

Using properly tuned gas appliances significantly enhances the safety of operation. When gas appliances are tuned correctly, it ensures that they operate within the manufacturer's specifications, which helps in reducing the risk of malfunctions that could lead to hazards such as gas leaks, explosions, or carbon monoxide poisoning. Proper tuning also often includes adjustments that optimize the combustion process, leading to more complete combustion of gas and minimizing the production of harmful byproducts.

For the other options, noise reduction may improve if the appliance is functioning optimally, but it is not a primary benefit associated with proper tuning. Ease of access refers to how easily one can reach or operate the appliance, which is largely unrelated to its tuning. Visual appeal concerns the aesthetic design or appearance of the appliance itself, which is not influenced by tuning. Thus, safety of operation stands out as the key aspect improved by ensuring gas appliances are properly tuned.