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Can I replace my existing hot water tank with a tankless unit?

Absolutely! The installation of these water heaters is very similar to your existing unit. Water, gas, and electric connections are very similar to the tank units. You may need heavier wire or multiple circuits for the electric models because of the larger instant current draw required. Typically these units hang on a wall rather than sit on the floor.

Remember, you can also install small point-of-use units under a sink or in a closet near a site where it always seems difficult to get hot water to run because of the distance from the point of origination. Most of the time you'll install an electric unit for this purpose which can use a standard outlet.

When choosing a tankless water heating unit you will want to consider where you need the hot water, how many demands will be placed on it at any given time, the flow rate of the unit you're considering, the incoming water temperature, and the desired temperature at the point of use. If you live in a cold climate, your incoming water is going to be much colder, and you will need a unit that can provide a greater gallons/minute rating. Talk to your dealer about your specific needs prior to making your purchase.

Can it handle a large demand like three showers at once?

This will all depend on the size of the unit you install, the temperature of the water coming into your house and the resulting temperature you desire for your showers. During the winter, when the water entering the heater is between 40 and 50 degrees, you may have difficulty with serving three showers at the same time. Similarly, you may have trouble providing multiple showers when a clothes washer or dishwasher are running simultaneously. For these situations, you may consider installing a smaller unit that is used only for your appliances and a separate unit for your bathing purposes. You may also install one at distant point of use sites. Generally speaking, gas-fired heaters can produce a higher flow rate than an electric unit.

Costs of installation?

This will vary according to the size of unit you select, the type of fuel required, and the amount of retrofitting that needs to be done to hook up to existing gas lines. The initial installation costs for a tankless water heater will be from 2 to 4 times as expensive than your traditional water heating tank. They can range in price from $200 for small under-sink units to over $1200 for a full-house gas-fired unit. The more hot water you require, the more you'll be paying for the unit.

How are they powered?

Tankless water heaters are powered by gas, propane, or electricity. There is some debate about the benefits of gas over electricity. Gas-fired heaters can usually provide a lot more hot water than the electrically powered ones. However, you may be losing your energy savings if your gas-fired unit has a pilot light that is constantly on. This cost varies for different models, so be sure to ask your manufacturer about this issue. There are models that use an intermittent ignition device (IID) that is similar to the spark ignition device that your gas stove uses to light the burner rather than relying on a pilot light.

How does it work?

Demand water heaters work by instantly heating water when a hot water tap is turned on. The cold water that comes into your house travels through a pipe inside the heater. The water is heated either by gas or by electricity, depending on the type of unit you select. There is no limit to the amount of hot water you can create in this manner. You will, however, be limited by the size of your unit and the rate at which it is able to heat water. Most can provide hot water at the rate of 2 to five gallons per minute.

How long do they last?

You can expect your tankless water to run for over 20 years. When you consider that most water heater tanks have to be replaced every ten years, this is a real bargain. These devices also come with easily replaceable parts allowing you to extend their functioning life by many years. Their warranties are also longer than a tank system.

How much does it save?

For homes that use about 40 gallons of hot water a day, you can expect to save between 25% and 34% in your energy costs than when you use a conventional hot water tank. For homes that use a great deal more hot water on a daily basis, this savings drops to around 10% - 15%. For these homes, you may wish to consider installing an on-demand water heater at each hot water outlet in your home that would provide a 27% - 50% energy savings overall. Talk to your installer about the best choice for your situation. Remember, when you are not using them, they cost you nothing in terms of energy!

What about installation and maintenance?

You will want to have a qualified plumbing and heating contractor do the installation for you. There is a lot to take into consideration, and they are the experts. They will take into account your fuel type, the climate where you live, any local building codes, and all safety issues. When hiring a contractor, get all estimate costs in writing and ask for references. You will have to perform some necessary maintenance from time to time, and the instructions for this are included in your owner's manual.

What is a tankless water heater?

A tankless water heater is an on-demand water heating system that immediately heats water when you turn on a hot water spout somewhere in your home. They are much smaller than a water heater tank and can be mounted outside for whole-house application, or near distant areas in your home where it takes a long time for hot water to reach that site.

What is the benefit over a tank water heater?

The U.S. is about the only country that uses water heating tanks. This results in a great deal of energy waste by keeping water hot in a tank while you're sleeping or away from your home for work or vacation. The rest of the world uses on-demand, tankless water heaters. When you are not using hot water, you are not consuming energy.

Where are they used?

They are used in homes and businesses throughout the world. Most installations are done outside unless you experience very low temperatures in the winter. In this case, you can have the unit installed inside your home. You can use a tankless water heater as the primary water heating source in your home or as a supplemental heating source for your solar hot water system on especially cold or cloudy days.