The problem of global warming due to emissions of greenhouse gases has become a major concern in recent years. Having experienced large changes in the prices of petroleum products, consumers are also becoming increasingly concerned with the environmental and economic loads imposed by home heating appliances. The concept of functionality evaluation was used to carry out a comparison of the features and merits of three air conditioners and three oil fan heaters in the author's home. The comparison covered start-up behavior after being switched on and stability in maintaining a set temperature. Carbon dioxide emissions and running cost were also evaluated. None of the tested appliances showed a general tendency to be superior or inferior in start-up or temperature maintenance, although results were obtained indicating that a particular appliance model could be better suited to some rooms or installation conditions than to others. The one clear merit emerged was that air conditioners are low in carbon dioxide emissions, which is significant for the mitigation of global warming.

Gas stove and oil stove has become a major cause of residential fires. Therefore, it is now legally required to install safety devices. In order to examine the effectiveness of this safety device, what consider whether the cooking stove is igniting due to the cause. Cause from there separately, we examined the effectiveness of safety devices for accident prevention, and consider the limitations of functionality. As a result, there are cases must be judged and confirmed by a person even if safety devices exist. Even within this case, it became clear that accidents will not disappear. Therefore, It is an important that the user should use the safety device as per the instruction manual without overconfidence, and the manufacturer should promote the design so that misuse of the product does not cause an accident as much as possible.