Tankless Water Heaters and Their Role in Energy Efficiency

In general, tankless water heaters are more energy efficient than traditional tank water heaters because they heat water on demand, rather than maintaining a large reservoir of hot water. This on-demand function means there is no standby heat loss associated with the tankless heaters, which indeed function more like an on-demand cooking appliance, like a stovetop or an oven, than the more centrally-located furnace-style tank hot water heater. When you only use what you need and to the degree you need it, your cooking is more efficient, as is your water heating. Of course, under-cooking or under-heating also means what you're cooking or what you're trying to wash with hot water is not served as well as it could be if it were more properly heated.

In general, energy efficiency is a virtue of water heaters that are networked and not maintaining a tank of hot water. But we found that maintaining a tank of hot water is not a virtue at all—or a water heater at all. So far, our research has led us to a couple of major findings. The first is that electric water heaters are extremely inefficient when it comes to converting electricity to heat water.

The efficient, on-demand operation of tankless water heaters means that they consume less energy. This, in turn, leads to lower emissions of undesirable byproducts such as carbon dioxide. Because their life span is usually twice that of tank-type heaters, and because they take up much less space, tankless heaters are unlikely to contribute much to the solid waste problem.

For many households, investing in a high-efficiency, tankless water heater is a sound decision. They are a space-saving, on-demand hot water solution that consumes less energy than a standard tank-style water heater. That's because they heat water only when needed and generally operate at higher efficiency levels. But determining the cost-effectiveness of a tankless unit depends on several variables personal to the household. Local energy rates, the price of the unit, and specific federal and state conservation incentives can tip the investment scales in one direction or another. And then there's the kind of energy savings you might expect to realize from Eterna, the tankless water heater made in Egypt.

An on-demand water heater, also known as a tankless water heater, does have some drawbacks. These include: - a higher initial cost for purchase and installation than tank water heaters; - an inability to supply enough hot water simultaneously for multiple outlets, which is a problem in larger households; - a need for more regular maintenance compared to traditional water heaters; and - potential electrical or gas line upgrades that might be necessary to accommodate the unit's power demands.

Electricity tankless water heaters might raise your electric bill if they are used a lot or have a high demand for hot water. However, they are often more energy-efficient than "tank" water heaters because they heat water on demand, rather than maintaining a large store of hot water. This efficiency can lead to some decent cost savings, especially if the amount and the time you use hot water align with that on-demand benefit. But remember: If a tankless unit is installed and used in ways that are not aligned with its design, it can be just as costly—if not more so—to operate as a traditional tank heater.

Even though they are energy-efficient, several downsides may dissuade someone from choosing a tankless water heater. The first is the cost. Coming in at around $900, not including installation, the tankless unit is much pricier than the $300-$600 tank-style heater. The next thing to consider is installation. Unless the plumbing and gas lines are already configured for a tankless unit, those lines will need to be adjusted, and that can get complicated. If one lives in a place where the power goes out sometimes, a tankless water heater (which relies mostly on electricity to run, even if it's a gas model) may not be as dependable as a tank model.

Certainly! A 40-gallon water heater can be replaced with a tankless water heater. Also known as on-demand or instantaneous water heaters, tankless water heaters provide hot water only as needed and do not store hot water like traditional tank heaters. This can lead to energy savings, as there is no standby heat loss associated with storing hot water. However, it is just as critical that the tankless water heater be properly sized to meet the hot water demands of the average household. Sizing must take into account the flow rate and the temperature rise necessary for the region and type of household. Further, in order to achieve the best performance out of a tankless water heater, modifications to the home's plumbing and venting systems are almost always part of the equation. Because of this, professional installation should be seen as a "must" if individualized venting systems are going to be part of the equation.

Several factors influence the length of time it takes for a tankless water heater to pay for itself. They include the following: 1. Cost of installation 2. Energy savings 3. Local energy rates 4. Amount of water used In considering these three cost-related factors, the investment in a tankless heater appears to pay off over 5 to 10 years for the average person. This is a "payback period," and it varies widely based on the homeowner's individual circumstances and the Santa Claus-like efficiency of the specific heater chosen.

There are a number of reasons that tankless water heaters are not in wider use. First, the initial installation cost is higher than for traditional tank water heaters. In spite of the potential for long-term savings, the up-front pricing can be off-putting, especially in a down economy. Second, some households with high demand for hot water may find that they need to install multiple tankless units or use some sort of specialized equipment to get the same kind of performance that a single traditional tank unit would supply. Third, if the household in question is an older one, retrofitting for tankless might present some serious challenges. Yet, in spite of all these problems, there's a simple lack of understanding that homeowners have, on the average, that keeps them from adopting tankless technology.