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Current and future renewable energy topics explained and discussed.
Tankless Water Heater Buying Guide
Pros and Cons of Buying Tankless Water Heater
The advantages and disadvantages of tankless water heaters are not completely clear for every situation. Sometimes an advantage can be a disadvantage or vice versa depending on your needs and desires. So, I present a list of the functional differences between systems for you to make up your own mind if buying a tankless water heater is right for you.
Tankless Water Heater
* Unlimited supply of hot water since it’s heated while passing through the unit.
* Increased energy savings as water is only heated when used rather than constantly heated.
* Take up less physical space leaving you room for storage or other needs.
* No risk of ruptured or failed tank flooding your house with water causing damage.
* Water conservation when equipped with a pump system as a result of water flowing only when hot.
* No need for a gas line if you have no other gas appliances in your house.
* Limited flow of hot water from system. Meaning you couldn’t have hot water for 3 showers at same time.
* May qualify for a federal tax deduction of up to $300.
Conventional Water Heater
* Lower initial purchasing cost although energy costs long term will result in higher overall expenses.
* When located next to water output hot water is nearly immediately available.
* If planning to sell home soon lower initial cost will result in higher profits.
* Unlimited flow of hot water from tank although it will run out much sooner.
* Can fill bath tubs much faster although you will be waiting awhile for hot water again after filling.
Besides the differences between conventional and tankless water heaters you should also be aware of the advantages and disadvantages between gas tankless water heaters and electric tankless water heaters which are discussed in the choosing right type of tankless water heater section.
How Tankless Water Heater Works
Tankless water heaters are really very simple. There is a cold water input pipe that feeds into the tankless water heater. This pipe passes by a heating element which gets extremely hot when activated by flowing water. After passing by this heating element the water is heated and continues through the pipe out of the heater and to the output that needs hot water. For example, your sink or laundry machine, etc.
There are two different types of tankless water heater, electric and gas powered. The only difference between these is the heating source. In an electric tankless water heater an electricity powered heating coil is used to heat the water and in a gas tankless water heater a gas powered burner will heat the water.
Tankless water heaters will output between 2-5 gallons of hot water per minute for the average system. Typically gas powered tankless water heaters produce higher flow rates than their electric counterparts. However, take into account that you’ll need a gas line whereas electric systems only need a standard outlet making them much more practical to install.
Choosing Right When You Buy Tankless Water Heater
When purchasing a tankless water heater there are many decisions you’ll need to make that depend on your situational needs. If you make a mistake you won’t be happy with the results of your tankless water heater and might even think that tankless water heaters just don’t work as well as conventional heaters just because you didn’t get the right flow rate or temprature model. Below are the major considerations to make when you buy tankless water heaters.
1) Fuel Type
There are two different fuel types to consider when you buy a tankless water heater. Electric and gas which each have some different advantages/disadvantages and requiremnts. Read below for a list of these and make sure what you pick works for you.
Electric Tankless Water Heater
* Support standard voltages 110V, 120V, 208V, 220V, 240V, and 277V.
* Amperage draw varies and you’ll need to ensure the circuit/breaker you use will support it.
* Will probably require additional wiring in your home for a dedicated circuit.
* Installation is easier in the sense that wiring is easier and more adaptable to run through home.
Gas Tankless Water Heater
* Need to determine if you’ll use natural gas or propane.
* Requirments may exceed existing gas line capabilities, inspect line to ensure it meets requiremnts.
* Usually higher flow rate compared to an electric tankless water heater.
* Have to install venting for exhaust from the gas tankless water heater.
* Purchase category III stainless steel venting for the exhaust.
* May require a minimal electricial connection in addition to gas line.
2) Size and Demand
In addition to fuel type you’ll also need to consider flow rate, temperature rise, and location when you buy a tankless water heater. There are different types of tankless water heaters that are designed for different purposes. For example, do you want hot water for a single fixture (single point), an entire room (multipoint), or an entire building (whole house).
Flow rate will need to be identified for every fixture you want to have hot water. If you plan to supply hot water to more than one fixture then add their flow rates to get a total needed from your tankless water heater. Here are some example flow rates for various fixtures in gallons per minute.
Shower – 1.5-3gpm, Bathtub – 2-4gpm, Dishwasher – 1-3gpm, Kitchen Sink – 1-1.5gpm. So, for example, if you have a bathroom with a shower and sink you’ll need a 3gpm flow rate if you just want the shower to have hot water when used. If you want the shower and the sink to have hot water at the same time you’d need 4.5gpm flow rate.
Getting the flow rate right is important because the temperature rise rating of your tankless water heater will depend on you using the rated flow rate. Most tankless water heaters are rated for multiple flow rates with different temperature rises resulting from different flow rates. For example, it might be rated as 50° rise at 1.5gpm or 35° rise at 2.5gpm, etc. You must know the incoming water temperature to know what the resulting temperature will be after heating. If you live where there is colder incoming water then you’ll need a higher temperature rise tankless water heater in order to meet your heating goals.
So, remember: Incoming Water Temperature, Flow Rate GPM, Temperature Rise Rating = Output Temperature