Conserve with Energy Efficient Hot Water Systems

September 2, 2010

Conserve with Energy Efficient Hot Water Systems

Hot Water Heaters

The energy needed to warm your water can account for a significant part of your monthly utility bill. However, there are several steps you can take to improve the efficiency and control the cost of your water heater. Water heating costs are affected by the type of water heater you have, its efficiency, its temperature setting and the number of gallons of hot water you use. Gas water heater costs account for about 16% of the average bill, while electric water heater costs account for about 28% of the average bill. Keep in mind, the higher the temperature setting of the water heater, the more it will cost to operate.

Tankless Water Heaters

Tankless Water heaters are also called on-demand water heaters. These provide hot water where you need it, when you need it, without a storage tank. Tankless water heaters, in some cases, can cut your water-heating bill by 10 to 20 percent. Energy savings are achieved by eliminating standby losses caused by warmed water sitting around unused in a tank.

Residential-sized gas-fired models that are now on the market supply only five gallons of water heated by 90 degrees per minute. a comfortable enough output for a house with one or two people. However, if you have a large family and need to do laundry and wash dishes at the same time others shower, a tankless system probably won’t meet your needs. Electric tankless heaters will produce a lower volume of heated water on demand and may not be suited for a large home.

Advantages to on-demand tankless water heating:

  • Compact in design and do not hold a large amount of standby heated water.
  • By providing warm water immediately where it’s used, tankless water heaters waste less water. People don’t need to let the water run as they wait for warm water to reach a remote faucet. A tankless water heater can provide unlimited hot water as long as it is operating within its capacity.
  • Equipment life may be longer than tank-type heaters because they are less subject to corrosion. Expected life of tankless water heaters is 20 years, compared to 10 to 15 years for tank-type water heaters.
  • Tankless water heaters range in price from $200 for a small under-sink unit up to $1000 for a gas-fired unit that delivers 5 gallons per minute. Typically, the more hot water the unit produces, the higher the cost.
  • In most cases, electric tankless water heaters will cost more to operate than gas tankless water heaters.

Disadvantages of tankless water heaters:

  • Tankless water heaters usually cannot supply enough hot water for simultaneous uses such as showers and laundry.
  • Unless your demand system has a feature called modulating temperature control, it may not heat water to a constant temperature at different flow rates. That means that water temperatures can fluctuate uncomfortably – particularly if the water pressure varies wildly in your own water system.
  • Electric units will draw more instantaneous power than tank-type water heaters. If electric rates include a demand charge, operation may be expensive.
  • Tankless gas water heaters require a direct vent or conventional flue. If a gas-powered unit has a pilot light, it can waste a lot of energy.

-Rob Pontarelli


Blog, Construction, Options and Upgrades, Think Green