Thinking of Switching to a Tankless Water Heater?

Traditional water heaters in American households, the round storage tank models, have been around for years and years. This has been slowly changing as the old tanks die out and homeowners try to find more eco-friendly, reliable and affordable ways to provide an unending supply of hot water to their families. I recently started shopping for a replacement for my 25 year old tank and put together some notes I though I'd share with you.

Solar hot water systems were (and still are) a very popular solution to powering water heaters. Having had one in a house years ago, I can say they saved a lot of money and it was a big plus to the buyers of our home when we sold. We are in a condo now, so that is not an option. with solar systems however, you still need to keep a holding tank, with about 40 to 80 gallons of water, supplied with a constant flow of energy, via the solar panels, to store the hot water. The problem with hot water tanks is that there is a significant amount of wasted energy when it is not being used. Also referred to as “standby heat loss” – it is the energy lost from having to keep the water in the holding tank hot until ready to use. The other problem is when the hot water runs out - you have to wait for the tank to refill and heat. Also, there's that big tank taking up valuable space in your home. Tankless hot water heaters solve both of those problems by heating water continuously, as needed – thus eliminating the need to keep a water tank hot, along with never running out of water.

The tankless method of heating water has been in use throughout Europe for many years, but it has only recently caught on in the United States. Also known as “instant water heaters,” “instantaneous,” or “on demand,” these water heaters do not use a tank. Instead, the water is heated when the hot-water tap is turned on and the water travels through a pipe, which runs through a heating element in the unit. This type of water heater might run on electric, gas, or propane, depending on the method of power used in the home.

As with any choice, there are benefits and always a few pitfalls that we don't find out sometimes until it is too late. So what are the benefits and pitfalls of switching to a tankless water heater? Basically two words - supply and cost.

Before you rush to buy a tankless heater, you need to understand their capabilities, so that you do not find yourself short of hot water. How could that happen? While the supply of hot water may be advertised as being "endless" tankless water heaters can only put out a certain volume of hot water at once, based on their size and flow rate.

Flow rate is the measure of water in gallons per minute (gpm) that the unit is capable of putting out. In order to determine the size and type of you need, the household size and estimated demands on appliances such as the dishwasher, washing machine and number of hot showers that might be taken while any or all of those appliances may be running. If you exceed the limits of any system’s flow rate, you will not have enough hot water.  In some cases, all you may need to do is to modify your washing schedule, so that you do not run too many appliances at one time. There are other solutions to the problem if modifying your routine is not an option. Installing a point-of-use water heater at certain locations would be one solution. That type of water heater is installed right at the water line supplying a particular appliance, the dishwasher for example, and it will only heat the water flowing directly into the machine. They are much less expensive than whole-house water heaters and appropriate where demand is at its greatest. Expense is another factor to consider.

The initial purchase is more expensive than conventional style hot water heaters, however the overall energy savings after a few years will make up for the cost in the long run. Points to consider – How large is your family? How long you plan to live in the home (a factor in calculating energy savings)? How much resale value will it add to the home? The more popular they become, the more people will be looking for them when shopping for a new home - it really depends on your individual location and trends. There has not been a lot of information published to date on what the actual return on investment (ROI) you would see, so at this point I would say that if you plan to stay in your house and it suits your family's needs, then make the choice that is best for you, and not in terms of selling.

Tips for Getting the Right Size Tankless Water Heater

Before shopping and talking to the professionals, it is a good idea to get a handle on your actual usage requirements so that they can pair your demands with the appropriate size unit.

When you try to calculate your most demanding hot water consumption period, start by listing how many hot water appliances or fixtures you may have operating at one time during a typical day. Then you will need to add up their flow rates – this will be your desired flow rate for a  tankless hot water heater. You will want to select the unit based on the maximum amount of hot water needed to meet your demand during peak use times. Following are some generalizations to help you get a ballpark estimate the amount of hot water you may use – depending on the type of fixtures and age of your appliances these figures can vary, but at least you have a ballpark figure to work around.

Faucets can use between one gallon (3.784 liters) and 2.5 gallons (9.46 liters) per minute.

For showers, figure in at least two gallons of water per shower. If you have installed low-flow showerheads then you can estimate just over one gallon to 2 gallons (7.57 liters) per minute. The old style shower heads can use anywhere from 2.5 gallons to 3.5 gallons (13.25 liters) per minute.

For a dishwasher or washing machine, count on about 2 gallons per minute. The other factor you will need to consider is the temperature rise needed. In order to do this, you will need to know the ground water or incoming water temperature. To calculate the rise needed, subtract that incoming water temperature from the desired hot water output temperature and the result will equal the rise. For example, say your incoming water temperature is 50 degrees Fahrenheit (10 Celsius) and you want the incoming hot water to reach a temperature of 120 degrees Fahrenheit (49 Celsius). Subtracting those 50 degrees from 120, the result is 70 degrees, which is the temperature rise you need. This is another thing you will need to take into consideration one many people don’t even think about because your location and year round climate will figure in to the power to bring that temperature up.

This is not a do-it-yourself project! Proper installation and maintenance of your tankless hot water heater is necessary to gain optimal energy efficiency. Because of the various types of tankless water heaters (electric, natural gas and propane) available, knowledge local building code requirements and safety issues, installation of the unit is best left to qualified professionals.

It is important to do your research before hiring a qualified plumbing and heating contractor to install your tankless water heating system. Check out the company with your local Better Business Bureau first. Then ask the contractor for their estimate in writing and inquire as to whether they will obtain any necessary permits from the local municipality, if necessary. It wouldn’t hurt to ask for references from previous customers, however this is not necessarily a reliable as they will surely only give you references from happy customers. Be sure that the contractor is up to date on local building codes as well as water heater insulation codes. It would be a good idea for you to contact the building department of your city or town directly for code and permit information too. This way you will know the answer your potential contractor should be giving you ahead of time.

We were hoping it would be possible to free up some valuable space by getting rid of the hot water tank. Unfortunately, living in an old condominium where the only option is electric, the cost to bring the electric amp up, rewiring and changing some plumbing lines may outweigh the benefits in my case.