Using the purchase price, annual energy cost, and an estimated cost of installation, we calculated the payback time for both new and replacement installations. Payback time was longer for a tankless unit that replaced an existing storage tank but more reasonable with new construction. Check our gas and electric water heater ratings for more. Tank water heaters typically hold 40, 50, or 55 gallons or more. The size you buy depends on the number of people living in your home and your peak water usage.
A family of four, for instance, might take several showers, run the dishwasher, and wash a load or two of laundry in an average day, totaling gallons of hot water or more. For storage tank water heaters, it's important to consider the first-hour rating, which is the number of gallons a water heater can deliver in an hour starting with a full tank. As the result of recently updated efficiency standards, water heaters less than 55 gallons now have a 4 percent boost in efficiency and water heaters 55 gallons or more have efficiency gains of 25 to 50 percent, depending on the technology used—heat pump or condensing.
See water heater types, below. And don't assume that a new water heater will fit where your old one was. Tankless water heaters, of course, don't hold much water, so the number to look for is the gallons-per-minute rating GPM.
The higher the GPM, the more hot water the unit can deliver. If you have a big family and multiple bathrooms, you'll need a tankless water heater with a higher GPM. A typical shower, for example, uses up to 2.
Newer washers use from 7 gallons front-loader to 19 gallons agitator top-loader per wash, but older models can use up to 32 gallons per load, as indicated below. Calculate your needs accordingly. For more, you can check our water heater ratings.
Some types are claimed to cut energy costs by up to half that of regular storage models. But their added up-front costs mean payback time might be longer. Storage tanks are the most common type of water heater. As the name suggests, these consist of an insulated tank in which water is heated and stored until needed, then emerges from a pipe on top of the water heater.
There is also a temperature- and pressure-relief valve, which opens if either exceeds a preset level. Natural-gas water heaters typically use less energy and cost less to run by about half than electric water heaters, although you should note that gas models cost more at the time of purchase.
Rather than storing water, tankless water heaters use heating coils to heat the water as you need it. Shop Tankless Water Heaters on Amazon. These capture heat from the air and transfer it to the water. They use about 60 percent less energy than standard electric water heaters.
And while they cost more than electric-only models, installation is similar and payback time is short. And because the heat pump is on top, a hybrid water heater needs as much as 7 feet of clearance from floor to ceiling. The best deliver stellar savings in summer, making them attractive for warm, sunny regions.
But savings suffer on cold and cloudy days. Most models employ a backup system that kicks in when needed. Shop Solar Water Heaters on Amazon. Condensing water heaters are an option if you heat with gas and need a unit with a capacity of more than 55 gallons.
In nearly all cases, the saving increases with increased household size. With that, you can determine if a notably larger purchase price is justified for your household. In some cases such as a leaking water tank — the water heat cannot be repaired, so replacement is your only option. However, if your water heater has stopped heating, there are several parts which have a modest replacement cost, making repairing the water heater perhaps the better option. Search Blog. Figure out the proper size for your household, not just in terms of gallon capacity, but first-hour rating as well.
This is particularly important with newer energy-efficient technologies. If possible, replace your existing water heater before it fails. Most water heaters have a lifespan of 10—15 years.
If yours is up there in age, have your plumber take a look at it and advise you on how much useful life it has left. Look for a water heater that satisfies your hot water needs and uses as little energy as possible. Storage water heaters are by far the most common type of water heater in use in the U.
Ranging in size from 20 to 80 gallons or larger and fueled by electricity, natural gas, propane, or oil, storage water heaters work by heating water in an insulated tank. When you turn on the hot water tap, hot water is pulled out of the top of the water heater and cold water flows into the bottom to replace it. The hot water is always there, ready for use. New energy-efficient storage water heaters contain higher levels of insulation around the tank to reduce this standby heat loss.
Efficiency and tank size. The energy efficiency of a storage water heater is indicated by its energy factor EF , an overall measure of efficiency based on the assumed use of 64 gallons of hot water per day, regardless of tank size. The first national appliance efficiency standards for water heaters took effect in Updated standards, effective in , are summarized in Table 6. All other things being equal, the smaller the water heater tank, the higher the efficiency rating.
Compared to small tanks, large tanks have a greater surface area, which increases heat loss from the tank and decreases the energy efficiency somewhat, as mentioned above. No residential-rated condensing water heaters energy factors 0. These have input capacity greater than 75, British thermal unit per hour Btuh. The minimum efficiency of electric resistance storage water heaters is about 0.
We do not recommend the use of electric resistance water heaters due to the high operating costs. A new electric water heater uses about 10 times more electricity than an average new refrigerator! Fortunately, heat pump water heaters using less than half as much electricity as conventional electric resistance water heaters are now available from several manufacturers—use the Enervee Score or check the ENERGY STAR lists for detailed information.
If you use electricity for water heating, consider installing a heat pump water heater. Sealed combustion. For safety concerns as well as energy efficiency, look for gas-fired water heater units with sealed combustion or power venting. This completely separates combustion air from house air. Power-vented units use a fan to pull or push air through the water heater — cooled combustion gases are vented to the outside, typically through a side-of-the-house vent.
Power-direct vent units combine a two-pipe system with a fan to assist in exhausting combustion gases. In very tight houses, drawing combustion air from the house and passively venting flue gases up the chimney can sometimes result in lower air pressure inside the house see Building Envelope. Demand or instantaneous water heaters do not have a storage tank. A gas burner or electric element heats water only when there is a demand.
Hot water never runs out, but the flow rate gallons of hot water per minute [gpm] may be limited. But if you have a couple of teenagers in the house, or if you need hot water for several tasks, a demand water heater might require staging some uses.
Newer instantaneous gas water heaters modulate their output over a broad range; typical outputs might range from 15, to , Btuh—a range in hot water output, depending on demand washing hands versus filling a clothes washer. This is an improvement over earlier models. However, there are still some significant issues with tankless water heaters.
First, they have a minimum water flow rate of 0. They also require regular maintenance, and performance in hard water areas is not well studied. Electric demand water heaters provide less hot water. Large units may require 40 to 60 amps at volts, beyond the wired capacity of conventional houses. If you want to consider an electric unit, make sure your electrical wiring can handle the job before you make a purchase. However, a small electric demand unit might make good sense in an addition or remote area of the house, thereby eliminating the heat losses through the hot water pipes to that area.
These losses often account for a large percentage of the energy wasted in water heating, regardless of the technology of the water heater. Demand water heaters make the most sense in homes with one or two occupants, and in households with small and easily coordinated hot water requirements.
Without modulating temperature control above , you and your family may find yourselves unhappy with fluctuating water temperatures — particularly if you have your own well water system with varying pressure. With gas-fired demand water heaters, keep in mind that a pilot light can waste a lot of energy.
In gas storage water heaters, energy from the pilot light is not all wasted because it heats the water in the tank. This is not the case with demand water heaters. A Btuh pilot light can consume 20 therms of gas per year, offsetting some of the savings you achieve by eliminating standby losses of a storage water heater.
To solve this problem, you can keep the pilot light off most of the time, and turn it on when you need hot water — a routine that should work fine in a vacation home, but not in a regular household. Among new demand water heaters sold in the United States, standing pilots have become very rare as almost all models use electronic ignition.
Manufacturers provide different specifications for demand water heaters: energy input Btuh for gas, kilowatts [kW] for electric ; temperature rise achievable at the rated flow; flow rate at the listed temperature rise; minimum flow rate required to fire the heating elements; availability of a modulating temperature control; and maximum water pressure.
Until there are industry-standard ratings for temperature rise and flow rates, it will be difficult to compare the performance of products from different companies. Many manufacturers now publish energy factor ratings for these products, and this information should make for easier comparisons. If you choose a tankless unit, look for one with EF 0.
Do not confuse a tankless coil with a tankless water heater or an indirect water heater. When hot water is drawn from the tap, the water circulates through a heat exchanger in the boiler. Tankless coils work great as long as the boiler is running regularly during the winter months , but during summer, spring, and fall, the boiler has to cycle on and off frequently, wasting a lot of energy.
Ready to Buy? Check out the Enervee Marketplace. The Air-Conditioning, Heating, and Refrigeration Institute lists high-efficiency water heaters on their website. Some of the most efficient water heaters find creative sources of heat— such as other heating equipment, outside air, or the sun — to provide hot water with less fuel.
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