What’s tankless water heater?
Tankless water heater is a type of water heating system that heats the water directly without the use of storage tank. Different from conventional water heating system, such system provides hot water only as its needed and thus, avoid standby energy wastage. When the hot water tap is turned on, cold water travels thru a pipe into the tankless water heater, the heating system will then heats the water (electric/gas) and deliver hot water on the user’s end.
Shopping for tankless water heater
When selecting tankless water heater, you’ll need to consider two main points: the fuel type, and the application.
Tankless water heater: Electrical vs Gas
In general you have two choices for the tankless water heater fuel type: Gas (or propane) or electrical. Each of the system has their own pros/cons and it’s very dependant to the user’s preference. For the ease to choose, here are the the disadvantages and advantages of each system.
| Fuel type | Advantages | Disadvantages |
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| Gas/propane powered |
Better energy efficiency: save more in operating cost. Generally more powerful: able to supply more hot water in the same time. |
Need special air ventilation: Extra installation or costs for renovation or venting accessories. Expensive: Higher unit cost as it’s usually meant for multiple bath room (or whole house) hot water supply |
| Electric powered |
Cheap: Cheaper unit cost as it’s usually meant for single bathroom hot water supply. |
Lower energy efficiency when compare with gas or propane powered water heater. |
Tankless water heater: Single vs multiple point
Number of supply point is another criteria for tankless water heater selection. Do you need single point of hot water supply (ie. just for shower) or multiple point (ie. shower and the sink)? Or move over, do you need hot water for single bathroom, or multiple bathrooms? In general, electric powered tankless water heater are normally used for single bathroom - multiple point or single point; while gas powered tankless water heater are normally used for larger scale of supply - the whole house, kitchen and bathroom, or multiple bathrooms.
Tankless water heater size
The size of tankless water heater is rated based on the maximum temperature rise possible at a given flow rate. Therefore, to size a demand water heater, you need to determine the flow rate and the temperature rise you’ll need for its application (whole house or a just a bathroom) in your home.
How to determine your flow rate demand?
It’s very simple to determine your house water flow rate demand. List the number of (hot)water devices you expect to use at any one time. By refering to table below, addup the flow rate of the water devices in your list - and that’s your demand of the tankless water heating system.
For example Joe’s family normally have two person taking shower in the same time, the demand flow rate is 3.0 + 3.0 = 6.0 gallon per minute (GPM). If Joe’s wife normally cooks while the rest are taking shower, then all we need to do is just add 1.5 GPM (kitchen sink) into 6.0, which make up to 7.5GPM. See! It’s really not that hard to get the numbers.
Choosing the right tankless water heater
Okay, we know you’re here for the shopping, not reading. Here’s some of our recommendation on tankless water heater according to different criteria.
Electrical tankless water heating system
For single bathroom, electrical powered tankless water heater (single point or multiple point) is recommended. Below are some of the choices you can look into. Specifically, we recommend Eemax EX65 for normal home usage.
| Single point (ie. just shower) | |
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The Eemax SP3512 "Single Point" Electric Tankless Water Heater to serve one commercial type sink as found in public hand washing areas, modular buildings and offices, strip malls, service stations and concession stands. Some of the example of Eemax SP3512 "Single Point" Electric Tankless Water Heater Applications are shopping malls, public hand washings, sink, office and Tenant Spaces, commercial buildings (restaurants, etc.), etc. |
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The Stiebel Eltron DHC 3-1 Electric Tankless Water Heater is designed for installation at the point of use. They heat water instantaneously as it flows through the unit. Stand-by losses are completely eliminated. The heating elements are controlled by a flow switch and by an exclusive scald-guard thermostat, which keeps the water temperature within safe limits at all times. |
| Multiple point (ie. shower and sink)/ Flow Controlled | |
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The Eemax EX65 "Flow Controlled" Electric Tankless Water Heater fits best for normal house used. Example of application include kitchen sinks, bar sinks, uitility sinks, dual handwash sinks, handset shower (0.7 - 2 GPM) etc. |
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Point-of-use hot water heaters can supply up to 2 sinks at a time and provide endless hot water and energy savings. These water heaters are easy to install and you will never have to worry about heat loss from long pipe runs. A point-of-use water heater is the perfect solution for home and office sinks… hot water without the wait. |
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Chronomite Tankless Electric Water Heaters is best used for lavatory, kitchen or Bar Sink. A good point about this model of tankless water heater is that no pressure & temperature relief valve needed unless required by local code. Chronomite S-23L product features and specification
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Gas/Propane tankless water heating system
With its high energy capacity and efficiency, gas or propane fueled fits the best for multiple bathroom usage. Check out these gas/propane tankless water heater for your references. Specifically, we think Rheem RTG-53 is a good buy and you should look on it in detail.
| Multiple bathrooms hot water supply | |
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Rheem is one of the major (award winnings!) players in the tankless water heater business. They have quite a lot of products in gas powered tankless water heating system. However, do not get confused by the oversized product list, the choice is simple when informed. If your home has 1-2 bathrooms, a Rheem RTG-53 series should provide an ample supply of continuous hot water. For up to 3 bathroom homes, the larger RTG-74 series water heater should be selected. Check out the product details for Rheem RTG-74, Rheem RTG-53. |
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Bosch GWH-635-ES-L Tankless Water Heater is ideal for households looking to maximize energy savings. The 635 ES requires no special tools to install or maintain. And its compact size and sealed combustion enables installation in small spaces. A built-in power vent makes both vertical and horizontal venting possible while the electronic ignition maximizes energy efficiency. This unit yields enough power to supply two showers simultaneously and features an adjustable temperature control for improved comfort. |
I want more choices!
Just in case you need more selections on the tankless water heater, you can get more shopping choices at PlumberSurplus.
