Water Heating

Did you know that for most homes water heat­ing is the third largest ener­gy expense, account­ing for about 15 per­cent of the month­ly elec­tric bill? And if your water heater is more than ten years old, it prob­a­bly has an effi­cien­cy rat­ing no high­er than 50 per­cent. To make mat­ters worse, an old water heater can oper­ate for years at reduced effi­cien­cy before it final­ly fails.

If you are like most home­own­ers, you will wait until your water heater dies before shop­ping for a replace­ment. But you can save your­self a lot of mon­ey over time if you do some research first. These tips will help.

A hand is outstretched under running water, droplets shimmering in the light, creating a serene and refreshing scene in an intimate setting.

Water Heater Efficiency

A water heater’s effi­cien­cy is mea­sured by its ener­gy fac­tor (EF). EF is based on recov­ery effi­cien­cy, stand­by loss­es and cycling loss­es. The high­er the EF, the more effi­cient the water heater. We rec­om­mend a EF rat­ing of .93 for water heaters under 60 gal­lons and .91 for water heaters 60 to 120 gal­lons.

To make the most of the unit’s effi­cien­cy, do not install it in an unheat­ed space. Also, try to min­i­mize the pip­ing to your bath­room and kitchen.

When choos­ing a water heater, it is wise to ana­lyze the life cycle cost — the total of all the costs and ben­e­fits dur­ing the appliance’s esti­mat­ed life­time. Units with longer war­ranties usu­al­ly have high­er price tags. The least expen­sive water heater to pur­chase is gen­er­al­ly the most expen­sive to oper­ate. Be sure to look at the annu­al cost to oper­ate the unit, found on the ener­gy guide label.

Sizing Your Water Heater

Although some con­sumers buy water heaters based on the size of the stor­age tank, the peak-hour demand capac­i­ty, or the first-hour rat­ing (FHR), pro­vid­ed on the ener­gy guide label is actu­al­ly more impor­tant. The FHR is a mea­sure of how much hot water the heater will deliv­er dur­ing a busy hour. Before you buy a water heater, esti­mate your house­hold’s peak-hour hot water demand and look for a unit with an FHR in that range.

Types of Water Heaters

With­in the last few years, a vari­ety of water heaters have become avail­able, includ­ing con­ven­tion­al stor­age mod­els, heat pump, tan­k­less (also known as point-of-use), indi­rect, and solar. It’s also pos­si­ble to buy a water heater that con­nects to your home’s space-heat­ing sys­tem.

STORAGE WATER HEATERS

 These heaters remain the most pop­u­lar for res­i­den­tial heat­ing needs. A stor­age heater oper­ates by releas­ing hot water from the top of the tank when the hot water tap is turned on. To replace that hot water, cold water enters the bot­tom of the tank, ensur­ing that the tank is always full. Because the water is con­stant­ly heat­ed in the tank, ener­gy can be wast­ed even when no faucet is on. This is called stand­by heat loss. New­er, more ener­gy-effi­cient stor­age mod­els can sig­nif­i­cant­ly reduce the amount of stand­by heat loss, mak­ing them much cheap­er to oper­ate. To deter­mine the most ener­gy-effi­cient mod­el, con­sult the heater’s ener­gy guide. This shows the esti­mat­ed annu­al cost to oper­ate the sys­tem and its ener­gy effi­cien­cy rat­ing.

HEAT PUMP WATER HEATERS

These water heaters move heat from one place to anoth­er, instead of gen­er­at­ing it direct­ly. To heat water for homes, heat pump water heaters work like refrig­er­a­tors in reverse. Heat pump water heaters are more effi­cient than con­ven­tion­al elec­tric water heaters. Though a heat pump water heater may have a high ini­tial cost, it can save up to 50 per­cent on your water heat­ing bill.

TANKLESS WATER HEATERS

Tan­k­less units are small heaters that pro­vide hot water on demand. They are installed near demand points, such as under kitchen sinks. A tan­k­less heater typ­i­cal­ly pro­vides one to two gal­lons of water per minute. Before installing a tan­k­less water heater in your home, make sure its reduced capac­i­ty will be ade­quate for your needs.

SOLAR WATER HEATERS

A solar water heater typ­i­cal­ly incor­po­rates pumps and con­trols to move heat-trans­fer flu­ids from col­lec­tors to a stor­age tank. Often they have con­ven­tion­al water heaters as back­up, or the solar sys­tem func­tions as a pre-heater for the con­ven­tion­al unit. Solar water heaters can reduce the annu­al fuel cost of sup­ply­ing hot water to your home by more than half. Dur­ing the sum­mer, they may pro­vide all the required heat.