Final answer:
The question concerns the installation and monitoring of gas-fired hot water heaters, emphasizing the necessity of professional installation and safety protocols like back draft monitoring and carbon monoxide prevention.
Step-by-step explanation:
The question pertains to the requirements for the installation and monitoring of gas-fired hot water heaters. To answer in 200 words, a gas-fired hot water heater needs to be installed by a licensed plumber to ensure it is set up correctly according to safety standards. Monitoring for back draft is crucial, as it can lead to dangerous situations where combustion gases are pulled back into the home, posing a risk of carbon monoxide poisoning and other hazards. The by-products of gas combustion need proper venting to prevent such risks.
Moreover, comparing the efficiency of gas water heaters and electric water heaters can provide insight into which method uses more total fossil fuel energy. A gas water heater might be about 85% efficient, while an electric water heater can be 100% efficient in transferring the electricity's energy into the water. However, the original source of electricity (if from a natural gas power plant) can significantly affect the overall fossil fuel energy used, considering the plant's efficiency and energy transmission losses.
Essential safety measures include proper ventilation, use of carbon monoxide detectors, and adherence to manufacturers' instructions when using gas-fired appliances.