Electric or gas?
In reality, there is no right answer to this question. What is better for one household might not be the best for another. The decision to select an electric or gas tankless water heater should be made with the homeowner or business’ individual circumstances in mind. The following factors all play a role in choosing what type of tankless water heater is best for your needs:
The availability of a convenient source of natural gas or propane and/or an adequate electrical supply to support another high-output appliance.
The relative cost of installation
The difference in cost between an appropriately sized electric and gas tankless water heater
Water usage habits and needs
Homeowner/ user preference
The differential between electric costs and gas costs in your area, and your personal outlook for changes in such costs in the future.
Desired installation location
Availability of Energy Source:
The availability of adequate electricity, natural gas, or propane, can obviously affect the decisions as to which type of tankless water heater is best for your home or business. Electric tankless water heaters are very high power appliances.
They heat water entirely on demand; their peak electricity needs are substantial even though their total energy consumption is much lower than traditional tank-type water heaters. Consequently, it is generally required that a home have a 200 amp, 208 to 240 volt electrical service to run an electric tankless water heater (some exceptions apply if you live in a warm climate region). Some homes or businesses do not have such electrical services available and upgrades can sometimes be expensive. On the other hand, the installation of a gas tankless water heater would almost
certainly be uneconomical if the building did not have an existing natural gas or propane service. Gas tankless water heaters are often well suited for installations in remote cabins etc. where electrical power is generally limited to a generator as they can be supplied with propane power.
Cost of Installation:
Unless an electric system/service upgrade is require, the installation of an electric tankless water heater is generally considerably cheaper than the installation of a gas tankless water heater. The reason for this is a gas tankless water heater requires ventilation like any gas burning appliance. In some cases, existing ventilation ductwork can be used, however, this might not always be the case.
Electric tankless water heaters cost less than their gas counterparts did.
Water Usage Habits & Needs:
For most homeowners and businesses, their water usage patterns and needs will not affect their choice of what type of water heater they should select. For families with heavier hot water needs, a gas tankless water heater can generally provide a higher flow rate than an electric tankless system.
Despite for decades their widespread safe use as home heating fuels, some homeowners do not feel comfortable using natural gas or propane. For piece of mind, in such instances, an electric tankless water heater is a better choice. Other homeowners may prefer one type for other reasons, including the availability of energy (electricity or gas) in the event of a major regional emergency such as a natural disaster. Still others may prefer one type to another for environmental reasons. Electric tankless water heaters are extremely energy efficient, with more than 98% of energy supplied to the units actually being used to heat the water. Gas tankless water heaters generally have an energy factor of less than 80%. Gas water heaters of all types contribute to greenhouse gases (although electric units could too if the electricity is generated by the power utility through the burning of fossil fuels).
Ongoing operating costs are obviously an important consideration. As a rule, gas tankless water heaters will cost about 10 to 20% less to operate than an electric tankless water system. This will depend greatly on the differential between natural gas or propane and electricity costs in your area. There are many regions where gas costs are extremely high due to the lack of supply in the region. In these areas, an electric unit can be significantly cheaper to operate. Remember, electric tankless water heaters are more energy efficient, so some of the cost difference between the fuels will be negated
Electric tankless water heaters are very small, about one-third the size of a gas tankless water heater. Because of their small size and the fact that they do not require ventilation of exhaust gases, they can be installed in many locations where it is not feasible to install a gas tankless water heater. Accordingly, electric tankless water heaters can often be located closer to the actual point-of-use.