Demand Hot Water
Demand hot water heaters are
fuelled with petroleum products (propane and natural gas). This product can
however save a substantial amount of energy especially when coupled with a solar hot
water heater. This provides a very efficient method of heating your hot water.
"Tankless water heaters are [a promising technology] that has
significant energy savings potential compared to conventional products. If these
products eventually achieve widespread market acceptance, tremendous gains in
energy savings and associated pollution prevention could be achieved." ...U.S.
Department of Energy, January 2004
It has been estimated that if we all used tankless hot water
heaters 91 million tons of
carbon dioxide could be kept out of the atmosphere every year.
Demand also called
instantaneous or tankless hot water heaters have been in use for more than 50 years in
Europe where energy costs are more than twice as high as in North America.
The energy consumption of demand hot water heaters is lower than of standby hot
water heaters because losses from the storage tank are eliminated. Demand water
heaters make the most sense in homes with natural gas or propane available.
The savings are achieved by
eliminating standby losses - energy wasted by warmed water sitting around unused
in a hot water storage tank. For
homes that use 41 gallons or less of hot water daily, demand water heaters can
be 24%–34% more energy efficient than conventional storage tank water heaters.
They can be 8%–14% more energy efficient for homes that use a lot of hot
water—around 86 gallons per day.
Proper installation
depends on many factors. These factors include fuel type, climate, local
building code requirements, and safety issues, especially concerning the
combustion of gas-fired water heaters. Therefore, it's best to have a qualified
plumbing and heating contractor install your demand water heater.
Most demand water heaters
have a life expectancy of more than 20 years. They have easily replaceable
parts that extend their life by many more years. In contrast, storage water
heaters last 10–15 years.
Periodic water heater
maintenance can significantly extend your demand water heater's life and
minimize loss of efficiency. Read your owner's manual for specific maintenance
recommendations.
What are it's Negative Features?
- SOME demand water heaters
cannot supply enough hot water for simultaneous uses such as showers
and laundry. (This can be eliminated by having a properly sized tankless water
heater or two of these hot heaters,
however, this comes at an additional expense.)
- Unless your demand
system has a feature called modulating temperature control, it may not heat
water to a constant temperature at different water flow rates. That means that water
temperatures can fluctuate uncomfortably - particularly if the water pressure
varies widely within your water system.
- Demand gas water
heaters may require a direct vent or conventional flue.
- If a gas-powered unit
has a pilot light, it can waste a la bit of energy.
As part our our service in
providing a solar water heating system to you
we will source and price the most cost effective solution demand based water
heater based on your needs.
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