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Home > Energy Efficiency Tips & Tools > Water > Upgrading Hot Water

Energy Efficiency Tips and Tools

Upgrading your hot water system

There are many ways to upgrade your hot water system that can have a quick impact on your costs. Find the ones most appropriate to your usage and start making improvements.

Install water-saving showerheads
Showerheads that provide satisfying showers using only 2-2.5 gallons per minute, in contrast to 5 or more gallons per minute, are also available. But be careful in your choice: all water-conserving or "low-flow" showerheads are not created equal! If the flow is too low, people may just stay in longer, using more water and defeating the purpose. Others are too harsh, and you will be showered with complaints if the showerhead doesn't give a truly comfortable shower.

Here's a simple test to see if your existing showerhead is efficient. Open an empty 2-litre cardboard milk carton and hold it up to the shower while it is fully on. If it fills in under 10 seconds, it is not energy efficient. You should consider replacing it.

In places like motels and athletic facilities, where showering uses a lot of hot water, energy saving showerheads can pay for themselves very quickly.

Install self-closing hot water faucets or a mixing valve
Proximity faucets which can be either electronically or ultrasonically operated, turn on automatically when the user's hands are under the faucet and off when the hands move away from the faucet.

Installing a single mixing valve is another approach to improving the efficiency of your water system. It prevents the waste of hot and cold water by reducing the time the water from two separate faucets would be on as the person tries to "mix" the water from two faucets in cupped hands.

Install flow restrictors and aerators in sink faucets
An aerator, which "spreads" the water, can be installed on a sink tap to assure a satisfactory yet lower flow of water from the tap. If you are going to replace faucets, some of the newer ones already come equipped with an aerator or a low-flow head.

Use labels at faucets
By placing a self-stick "Please Turn Off the Water" label near each sink, bath or shower faucet, you can encourage people to conserve both water and energy.

Consider changing to a high efficiency water heater
If you are replacing your water heater, evaluate premium efficiency replacement units. The table below shows the performance that you might expect from premium efficiency replacement water heaters. Compare choices using the electricity and natural gas costs that you experience in your area.

Efficiency of Water Heater
Energy Factor
Type of Water Heater
Typical New Unit
Most Efficient on Market
Oil-fired 48 - 53% 60 - 63%
Gas-fired 51 - 56% 71 - 86%
Electric resistance 87 - 91% 96 - 98%
Electric heat pump 250 - 350% 310 - 350%
Efficiency ("energy factor") is the annual energy input divided by the annual energy output in consistent units (BTUs or kWhs).

Install the new water heater closer to the point of use
If you are replacing an old heater, or installing one for the first time, locate it close to the major point of use (washing machine, etc.) to minimize heat losses in the distribution pipes.

Replace a tankless coil with a different type heater
In some buildings, water is heated by the central heating system by means of a "tankless coil" installed in a gas-fired or oil-fired boiler. These systems have little or no storage capacity, so the entire furnace or boiler must operate to heat even a small amount of water. If your hot water needs are small or your heating loads are low, replace this unit with an efficient storage tank type water heater or with small "local" heaters.

Switch to "local" storage tank type heaters
A large central heater with long runs of distribution piping can waste a lot of heat energy, particularly if it is poorly insulated and if there is relatively little need for hot water. Depending on your hot water needs and the age and efficiency of the existing system, it may make sense to abandon the old system and replace it with one or more small storage tank type water heaters very close to the faucets or other points of hot water use (e.g., one in each lavatory).

Install a heat reclamation device
One of the most intriguing ways to save energy dollars is to recapture and reuse "waste" heat before it has been truly lost. In a commercial laundry or restaurant, for instance, heat in the to-be-discarded washing or rinsing water may be recaptured before the water goes down the drain, and used to pre-heat fresh, cold water. The two water supplies are kept separate and the heat is transferred through a heat "exchanger" or "reclaimer".

Saving energy in your cold water system
A water cooler uses electricity cooling and re-cooling the water round the clock, even though most of the time the water isn't being drawn (another example of "stand-by" energy losses). You may be able to raise the chilled water temperature or to disconnect the refrigeration unit by removing the cover and disconnecting the compressor.

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