Tankless Water Heater ComparisonsThe Inefficient Tank Water Heater
Traditional electric or gas tank water heaters have been used in commercial and residential properties since the early twentieth century. Conventional tank heaters use a simple heating element and tank technology that, with the exception of some fairly recent gains in the area of energy efficiency, have remained virtually unchanged over the last 25 years.
Most Conventional tank heaters have upper and lower heating elements, one of which is cycling on or off 24 hours per day, even when you're not at home. This raises your heating bill, even when you aren't using water. Even worse, with a Conventional tank heater, you are heating water to a ridiculously high temperature in order to maximize the available supply of hot water. When water reaches the tap, cold water must then be added so that the temperature is comfortable to the human touch. This process of heating water wastes valuable energy, not to mention water and money. When a hot water faucet is activated, the Conventional tank heater is replenishing the tank with cold water at the same time, lowering the overall water temperature in the tank. This triggers the element to draw more power to reheat the water to the desired set temperature.
Because of this inefficient process, a 60-gallon tank only has 45 gallons of useable hot water. The other 15 gallons are lost as cold water is added to the tank during the usage process.
In addition, a Conventional tank heater is constantly radiating heat (loss), which also contributes to the re-heating rate and energy consumption. This type of heat loss is often referred to as "stand-by" heat loss. By eliminating stand-by heat loss alone, energy consumption can be reduced from 20 to 30%.
Consider the following comparative
|Tank Water Heaters||Tankless Water Heaters|
|Constantly heat and re-heat water||Heats water only when needed.|
|Lasts between 2-10 years||Lasts for a lifetime.|
|80% efficiency the first year and then declines as heater ages.||99%+ efficiency for life of heater.|
|Destined to Leak||Less likely to leak|
|Average energy Factor of .58||Energy factor of .98+|
Yearly cost savings comparisons for tankless heating systems compared to traditional electric and gas tank heating systems are attached as Appendix 1. These comparisons are based on the U.S. Department of Energy Hot Water Usage Guidelines as reported on the Energy Efficiency and Renewable Energy Clearing-House. Energy Factor and Average Annual Operating Costs based on D.O.E. (Department of Energy) test procedures. http://www.eren.doe.gov/femp/procurement/calc_waterhtr.shtml
As stated above, the average storage tank hot water heater has a lifespan of 8-10 years, with more than 7.3 million tank water heaters discarded into U.S. landfills annually. Every part of our tankless water heater is replaceable and therefore helps significantly reduce the amount of waste material that ends up in landfills every year.
The Environmental Costs of Energy
Water heating accounts for 20-30% of energy use in North American homes. This energy comes from hydroelectric power generation, the burning of the following fossil fuels (coal, oil, natural gas) and nuclear power. None are without environmental impacts. All lead to long-term significant and lasting environmental degradation that may include harmful waste bi-products, expensive remediation costs, depletion of the natural resource base, and wildlife habitat loss and biodiversity threats.
Reducing the amount of energy used to heat water will reduce the amount of fossil fuels consumed and therefore the amount of resulting greenhouse gas emissions. A 50% reduction in energy consumption could result in a 50% reduction in the harmful effects, resource depletion, and infrastructure costs of supplying that power.
It has been reported that if wasteful tank heaters were replaced with high-efficiency tankless models, North American society could annually save:
· 290 million gallons of fuel
oil a year;
· 164 million gallons of propane or
· 6 billion hours of kilowatt electricity
Energy Saving Facts
The U.S. Department of Energy's Energy
Efficiency and Renewable Energy Network released a brief (see Appendix
2) on the benefits of demand (tankless or instantaneous) water heaters
for energy efficiency where it is stated that Water heating accounts
for 20% or more of an average household's annual energy expenditures.
Since water heating is often the largest single component of energy
expenditure in many households, a reduction of 50% of this component
can result in significant overall savings. This US government document
is somewhat dated, and our tankless water heaters were not part
of the evaluation process used to reach the conclusions contained
therein. Nevertheless, we believe most of the information is correct
except that our tankless water heaters provide greater ease of use
for whole house applications and offer greater savings potential
as a result of the superior state of the art technology.
Why heat water that is not being utilized?
Most energy-saving tips suggest insulating storage water heaters to conserve energy - but even the best-insulated tanks will constantly reheat the same unused water. Far more cost-effective is the tankless system, which heats water only while you use it.
Bacterial Respiratory Disease Health
One health concern associated with traditional water heaters is Legionnaire's disease, a bacterial respiratory disease similar to pneumonia. Thousands of cases of Legionnaire's disease occur in the U.S. each year, and up to 15% of the cases are fatal. Most often, smokers, the elderly and those with chronic respiratory problems or compromised immune systems.
A 1984 study (Ciesieki et al) reported that the bacterial cause of Legionnaire's disease (Legionelia pneumophila) is capable of colonizing in hot water systems maintained at 115° or lower.
The 1995 ASHRAE (Stiebel Eltron Society of Heating, Refrigerating and Air Conditioning Engineers) Applications Handbook notes that "segments of service water systems in which the water stagnates (e.g., shower heads, faucet aerators, and certain sections of storage-type water heaters) provide ideal breeding locations" for the bacteria.