Aug 16, 2018

5 Things to Consider When Purchasing New Hot Water Heaters

In the last few years, the water heating industry has seen a few shakeups thanks in part to higher water heater efficiency mandates, new technology, and consumers moving away from tank-type water heaters. This has left many homeowners confused on what water heater to purchase. So if you’re in the market for a new hot water heater, here are five considerations will help you to make an informed decision.

While new storage water heaters are more efficient, they have had to grow in size.

If you have done any online research, you have probably come across the acronym “NAECA 3”. NAECA, or the National Appliance Energy Conservation Act, regulates the energy consumption of certain major household appliances. The latest revision, NAECA 3, went into effect in April 2015, calling for higher water heater energy efficiency ratings. Tanks now have to be better insulated to minimize heat loss (think same volume, with more insulation making the tank larger), and in some instances, supplemented by other water heating solutions.

What does NAECA 3 mean for homeowners?

If your existing tank was purchased prior to the NAECA 3 regulation revision, expect your next tank to grow in size by at least 2” in height and 2” in diameter.


This increase in size only allows more room for insulation, not usable hot water. Also, traditional tanks over 55+ gallons are no longer available.

If you are looking for a 55+ gallon electric tank water heater, you will have to purchase a hybrid or heat pump, or a condensate tank if your fuel type is natural gas. Heat pump and hybrid tanks start at almost double what you would typically pay for a traditional tank water heater. Further, some gas condensate tanks cost almost three times as much as a traditional gas storage tank. So, if your current tank is larger than 55 gallons you will need to think about a new solution before it is time to replace your hot water heater.

Prior to purchasing a new hot water heater, be sure your existing space will accommodate outfitting for a larger tank or check whether or not your hot water needs can be fulfilled by a smaller capacity tank. In many cases, the best long term solution is to replace the tank with a more energy-efficient tankless hot water heater. You can learn more about the NAECA 3 regulations on the Department of Energy’s website.

Should you heat water using propane, natural gas, or electricity?

When shopping for your next water heater, your fuel source will be the first variable to consider when sorting through options. In general, costs associated with heating water will be higher when using propane because the fuel is more expensive than natural gas. Electricity and natural gas are more common fuel sources, with the latter tending to be least expensive. 

After determining your fuel source, the next step is to decide if you are going to heat your water with electricity or natural gas. Almost every home has electricity, but not all homes have access to natural gas. If you only have electricity at your home, it is often cheaper to continue using that fuel source for water heating over paying to bury a propane tank or run a new natural gas line (if that is even a possibility). Keep in mind, there is always a direct relationship between the amount of power in and the output temperature of your hot water. Always. So, it is important to determine how much power you have in your home. This is typically referred to as the service load for the dwelling and is either marked on your main breaker panel or can be calculated by an electrician.

More power means more hot water (at a constant flow rate). Heatworks, and other tankless electric water heater companies have sizing resources available to help you determine how much power is needed in order to meet your hot water demand. Most standard tank-type electric water heaters are wired for 30 amps and 220 volts, yet, most tankless units require more than 30 amps in order to get your water hot enough.

However, since the Heatworks and other tankless systems only draw power when hot water is being drawn, you will not be wasting energy heating a tank for 20-24 hours per day when the average home uses just over one hour of hot water per day. This difference in usage is where savings in operational costs can be made up with tankless. Depending on the service load of your home, you may need an electrician to install a larger breaker to provide you with enough power. Check out Heatworks’ sizing resources here.

One notable consideration when dealing with natural gas is making the jump from tank to tankless. Tank-type natural gas hot water heaters use ½” gas lines, while tankless hot water heaters require ¾” gas lines. Though some tankless companies have started making tankless water heaters at a lower BTU rating to accommodate an existing gas line, you will want to look at the cost of outfitting the space and reworking the piping if you are moving from tank-type to tankless. (In addition to the gas line piping, proper ventilation is extremely important when dealing with natural gas water heaters.) Although Heatworks' tankless electric water heaters cannot be powered using natural gas, they can be installed at the point-of-use or as a booster to supplement the existing hot water source. Tankless electric water heater installation costs are not much different than the cost of installing an electric tank-type water heater.

Where is your hot water heater located?

We have already discussed how the NAECA 3 requirements may mean that installing a new, same sized water heater as the existing unit is not possible. We have heard horror stories of people trying to outfit their existing utility or water heater closet to fit their larger tank, only to find out that it would not fit in the existing space and required them to build-out the space to accommodate the larger tank. If replacing your current tank with a larger NAECA 3 tank is not an option, consider downsizing to a tankless unit in order to solve your problem without sacrificing available hot waterRemember, most tanks are wired for 30 amp service, so be aware of the power requirements for the tankless unit prior to buying. You may need to upgrade your wiring and/or breaker size for sufficient hot water output.

While you're at it, you may want to consider changing the placement of your hot water heater as well. Why? Perhaps you have to wait a long time for the hot water to arrive at your master bath. Or, you are a family of five and find you’re running out of hot water too fast before everyone showers at night. You may want to consider placing your new hot water heater closer to the point(s)-of-use, or, in a more centralized location to help alleviate these pain points as well. To see how the MODEL 3 Water Heater can be configured in your home or business, click here.

What is your starting groundwater temperature? 

With tankless electric water heaters, you need to be sure your home is sized properly. This means calculating how much power is needed to achieve the desired temperature. Groundwater temperature is important because that is your starting point. If you live in a colder climate, it is going to take more power to heat your water to 104° F, which is the average shower temperature, than if you lived in a warmer climate. Groundwater temperature maps should be used to determine the groundwater temperature in your area.

Measuring the temperature of the water coming from an outdoor spigot may not be accurate and often leads to undersizing as groundwater temperatures fluctuate between winter and summer months. In the world of tankless electric water heaters, Joe from New York is going to need more power to achieve the same temperature of hot water as Jane from Florida. This is simply because Joe is starting with groundwater ~47° F and Jane’s groundwater is ~75° F. In most cases, a larger breaker can be installed in the existing panel to provide more power, inexpensively. Remember, with tankless, there is no preheated reservoir of water. This means you won’t run out of hot water, but you need enough power to heat the water to your desired output temperature on demand.

How much hot water do you use at any one given time? 

Flow rate refers to the rate water flows from the installed hot water fixtures. With tankless electric water heaters, there is a direct relationship between the flow rate of a fixture (demand), the power supplied to the tankless electric water heater, and the output temperature of the hot water. The higher the flow rate, the lower the temperature (if power in remains constant).

Many tankless units cannot keep up with the demands of high-flow fixtures, such as rain shower heads and spa tubs.


Often, tanks run out of hot water when supplying to these high-flow fixtures as well. Because of this, as well as many green initiatives, it is often recommended to use low flow fixtures when possible. Some states, like California, even have laws governing the use of high- and low-flow fixtures. 

So, purchasing a hot water heater is a big deal — there is a lot more to it than just the sticker price. Keep in mind compliance with new energy efficient standards, powering the unit, where the unit lives in your home, your groundwater temperature, and the types of fixtures you are comfortable using. Use sizing resources available and ask your local appliance store associate for guidance. Enjoy your next hot shower with piece of mind that you made the best choice for you and your family’s hot water needs.


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