Gas vs Electric tankless water heater
A tankless water heater is a type of water heater that heats up a flow of cold water only as the hot water is used. There’s no need to wait for a tank to fill up with enough hot water. It is capable of delivering an endless flow of hot water, and this type of system is very convenient in terms of saving energy and money.
This article will compare two types of tankless heaters: gas vs electric. In order to help consumers, many websites have published comparisons between various models from different companies. This article is based on those studies as well as our own research.
How does a gas tankless water heater work?
To understand how a gas tankless water heater works, it is important to know the working principle of a tankless water heater. In addition, you need to be familiar with the different parts of gas tankless water heaters and how they work together.
The most essential part of a gas tankless water heater is the element, which has a long life expectancy and requires little maintenance beyond replacing its anode rod every three to five years. It heats up cold tap water going inside it with electric resistance heating.
The heat exchanger cools down this hot water and sends it back to the faucet for use in the shower, bathroom, or kitchen sink. However, when there’s no need for hot water, such as in the middle of the night or when no one is home, this system will not waste any resources by keeping all parts working at maximum capacity.
Features of gas tankless water heater:
- Can be mounted to the wall
- More power than an electric tankless water heater
- Does not need an electric outlet nearby, provided gas line is already there
- Customizable output for different styles of homes (large or small household)
- Higher initial cost, but the lower overall cost to own. Performance has been known to last longer with less maintenance & repairs over the life of the unit.
- Higher flow rates – can service multiple appliances at once without sacrificing performance or energy efficiency
- Gas units require no auxiliary power/standby heat source due to its internal design allowing it to function w/o being connected to a separate tank for stored heated water
- Gas units require no electricity – therefore it is not affected by power outages or disconnections unlike electric units
- Many models are available for mobile homes, travel trailers, etc. to be able to install one at any residence/property were providing an electrical outlet is difficult or impractical. Those with RV’s can take their tanks with them anywhere within range of an LPG (propane) delivery point and connect the unit to their existing LP supply
How does an electric tankless water heater work?
The most common type of electric tankless water heater is a non-condensing unit. This type of system heats up cold tap water using an electric element located inside the tankless water heater and sends this hot water out to the faucet. In order to get hot water, consumers have to wait for enough cold water to go into it for heating.
Compared with gas units, they require a nearby electrical outlet and need electricity or a standby heat source which means that they are sensitive to power outages.
Electric tankless models consume a lot less energy compared with traditional storage-type models since their heating elements only turn on when there’s demand for hot water.
Features of electric tankless water heater:
- Can be wall or floor mounted
- Smaller than a gas unit
- Can be used as an addition to any existing tank heater within the home (tankless water heaters do not function as a primary source of hot water for your home) to supplement or maintain flow rates in situations where demand is high due to more people being present, taking long showers, frequent use of faucets, etc.
- Quieter than a water heater that uses natural gas due to its lower energy consumption
- Lower initial cost, but higher overall cost over the life of the unit
- Electricity required – therefore it is affected by power outages or disconnections unlike gas units
- Lower flow rates – can service only one appliance at a time without sacrificing performance or energy efficiency
- Requires an electrical outlet nearby, provided the line is already present for use of other equipment in the home. The electrical outlet should be within ~ 10 feet of the water heater
- Most manufacturers do not provide mobile & off-grid options for electric water heaters. Some models are available for RVs, travel trailers, etc.
Which type is cheaper?
A heating element in a gas tankless water heater creates hot water on-demand, which means that you only pay for what you use. In homes where there is a high demand for hot water, it can help to reduce overall energy costs by using a smaller capacity unit.
Since the electric models only have one setting, you’re paying for maximum output regardless of how much hot water your household actually needs at any given time. The payback period may be longer, but over time the total savings from this type of system can be worth it since there is no minimum storage cost or surcharge fee associated with owning an electric unit.
Commonly installed prices for gas-powered tankless units are between $1,300 and $2,000 while electric water heaters can be purchased for about $700 to $3,000 depending on the capacity and manufacturer. Some higher-end electric models may include advanced features such as built-in controls or remote access via a smartphone app.
What tankless water heater is more efficient?
Both types of units are nearly equally efficient. Electricity is more cost-effective than gas, but since the price of gas fluctuates frequently based on supply and demand.
Is either one better for the environment?
Electric tankless water heaters produce less carbon dioxide emissions over their lifetime compared to gas models which can be used for longer periods of time without compromising efficiency. Electric water heaters also don’t require maintenance while gas models need annual systems checks recommended by qualified professionals.
Furthermore, if you have an electric unit that’s connected to a renewable energy source such as solar, then you’re not only getting environmentally friendly hot water but also reducing your home utility bills since most states offer rebates and tax credits when you use solar energy at home.
What about the installation?
Electric models are easier to install in a home with an existing water heater since they require an electrical outlet nearby and don’t need gas connections, venting, or running gas lines. They also avoid complicated safety concerns related to carbon monoxide poisoning.
For example, low oxygen conditions such as could occur in a house that has been flooded or is engulfed by smoke during a fire can cause dangerous levels of carbon monoxide to accumulate inside which can lead to suffocation and death. If there’s no ventilation system installed in the building you might also have similar issues due to gas heaters.
As for tankless units that use propane instead of natural gas, the fuel must be stored on-site and vented properly so there is no risk of carbon monoxide poisoning.
Do they need special maintenance?
Gas-powered systems require annual service by professionals who will conduct an inspection to ensure that all safety precautions are followed according to local regulations.
Electric units use high-quality elements which don’t require regular servicing aside from making sure that there is adequate ventilation in the surrounding area. If it becomes too hot and starts to malfunction, the built-in thermal cut-off feature will turn it off.
What about usage?
The average American family uses around 70 gallons of water per day with a hot water consumption rate of 5.2%. This means that in every home where there is someone using the shower or taking a bath for 10 minutes, washing hands and dishes, filling up a pot for cooking and running the dishwasher, there could be an extra 50 gallons or more users which may not be necessary if you have a tankless system.
The convenience of having unlimited amounts of hot water on demand can also help encourage conservation in households since people aren’t limited by their past habits when it comes to how long they spend in the shower each day.
Usage of a gas tankless water heater is dependent on the outside temperature and the size of the water also affects how much gas is required. Your unit’s heating capacity is based on its Btu output which means that it will be able to heat a certain amount of water per hour for each degree below 212 degrees Fahrenheit.
If you want to calculate your system’s heating rate just use this formula: BTU/HR = 10 x SHF where SHF stands for shower head flow measured in gallons per minute. This can then be used with an indoor water supply temperature to determine your total hot water usage by dividing the result by 80% to account for low-flow fixtures, toilets, etc.
The usage of an electric tankless water heater is the same as a regular tank model since both of these types will provide you with unlimited amounts of hot water.
The only difference is that the energy used to power them must come from somewhere and your utility bills will depend on which source your home uses such as conventional natural gas or electricity. Electric units are more efficient in this aspect because there’s no additional fuel required beyond what’s already being used for heating and cooking purposes.
Other considerations when choosing between gas and electric water heaters
There are also other things that you should consider when researching what type will work best for your home.
One major consideration is the size of your household since larger homes with multiple bathrooms and sources of hot water usage may require bigger capacity ( gallons per minute ) tankless systems in order to provide enough heated water. You don’t want to make a purchase only to find out later on that it’s not powerful enough to meet your daily needs.
Another thing to think about is how much propane or electricity costs in your area, especially if you’re switching from conventional tank heaters which normally use natural gas. Electric rates vary depending on where you live but just remember that each gallon equivalent used by an electric system will cost more than one ignited with natural gas.
Finally, you should check to see what’s required in your area before the installation of a tankless system. There may be rules and regulations about permitting or inspection that must be met by homeowners who want to switch from conventional storage models because the additional power source needed for an electric unit may not be compatible with older buildings.
This is generally not an issue when upgrading to natural gas since its use is already common across homes and offices throughout the country.