Water Heating - Instantaneous Water Heaters
Technology Snapshot & Benefits:
Easy economic savings can
accrue from instantaneous or the "on-demand" type of water heaters. In contrast
to the traditional method of keeping 40 to 80 gallons of hot water at-the-ready
in an insulated tank, "on-demand" heaters produce hot water only when it is
needed. Since hot water is generally required for less than a few hours each
day instead of 24, owners and occupants can easily benefit from high efficiency
modern designs that provide hot water on demand. Less fuel is required for a
given volume and temperature of water, with corresponding cost savings and
pollution savings. Some manufacturers claim 50% savings when compared to
conventional hot water tanks.
Estimated Cost Savings:
Assuming that you consume the
same amount of hot water at the same temperature as before, you can save a lot
of energy and money by eliminating the slow leakage of heat from the hot water
tank and piping. Actual savings will depend upon how much water you use, how
far it must be piped from your existing heater, and the extent to which that
piping travels through unheated spaces. It is reasonable to expect improvements
in your hot water bill of 20 cents on the dollar. For a monthly water-heating
cost of $50 dollars, you may expect savings of $10 per month on your energy
bill. If the switch to "on-demand" water heating is made when your old hot
water tank conks out, the effective net cost of change will be much lower and
your monthly cash-flow will improve immediately.
Installation will be required
in the immediate vicinity of bathroom, kitchen and/or laundry room. Space may
be a concern.
If the new units are
electric, you may wish to consider the stability of the electrical grid in your
part of the country. Additionally, electricity is most often produced by large
central-station plants and is delivered to you at an overall efficiency of about
30%. Unless your electricity is produced with renewable energy equipment,
natural gas or LP gas are the fuels of choice for hot-water heating (just as
with traditional hot water tanks). These fuels provide total system
efficiencies of 80-90%.
Installation (Getting It Done):
If the new water heaters are fueled by natural gas or LP gas, there may be some
fuel delivery piping and exhaust venting issues to be addressed by the
installer. If the new units are electric, expect some minor rewiring and the
installation of new circuit breakers.
Be sure to get bids from at least two or three installers and/or plumbing
contractors to gain immediate perspective on the true costs of equipment and
installation in your area.
Videos On This Topic:
From EcoBroker International:
From Other Sources:
How Does a Tankless Hot Water Heater Work? (1:15) - eHow -
water heaters are wonderful ways to save money on energy bills because they
unnecessary water heating that doesn't get used. In this video, find out how
they work and how they are different from tank water heaters.
Hot Water Heater Blanket (2:35) - Sierra Club Green Homes -
One of the best
and cheapest ways to increase the efficiency of your water heater is to install
a heater blanket to help insulate it and prevent heat from escaping. In this
video from the Sierra Club, watch a step-by-step guide to wrapping your water
heater, an investment that will pay for itself in just a few months.
Install a Propane Tankless Water Heater (4:49) - This Old House -
water heaters can save homeowners significant amounts of money every year on
heating bills. To find out more about installing them, watch this video from
This Old House featuring plumbing and heating expert Richart Trethewey.
Information On This Topic:
Department of Energy, Office of Energy Efficiency and Renewable Energy - Demand
(Tankless or Instantaneous) Water Heaters