Tankless Water Buyer's Guide

At HotWaterSource.com we are focused on educating consumers about tankless water heaters and helping them find the right model to meet their water heating needs. We will provide you with Energy Savings Information, easy to use Comparison Charts, and a comprehensive Buyer's Guide, as well as detailed product information so that you can be sure you're getting the right unit for your home. Because we only sell tankless water heaters, we can offer you a level of service and expertise that nobody else can. We offer a LOW PRICE GUARANTEE so that you can be confident you are getting the best deal around. And we're so confident that we'll sell you the right tankless water heater we offer a 30 day return policy on the tankless water heater you buy from us. Feel free to call us and and talk to one of our knowledgeable tankless water heater experts.
Tankless Water Heaters : An Overview
Most people in North America currently use a storage tank water heater to provide hot water in their homes. A storage tank water heater constantly heats the water stored throughout the day even while you are at work or sleeping. A tankless water heater, on the other hand, does not store hot water. It heats the water as you use it. How does this work? When you open a faucet, the flow of the water triggers the heater to turn on. Whether you use gas or electricity, the powerful gas burners or electrical elements will turn on, rapidly heating the water as it passes through the unit. The water is heated instantly, and the time it takes to obtain hot water is directly related to the distance the hot water has to travel from the water heater to where hot water is being used. The burners or elements then shut down when you shut off the hot water. The energy that is consumed is only for the hot water that is being used which is why tankless water heater can save you a substantial amount of money off of your electricity bills. Depending on which model of tankless water heater you purchase, and what size storage tank you have now, and if it runs on gas or electricity, you could save anywhere from 5% to 69% off your hot water heating bill. How? Most homes use hot water for a cumulative total of about one hour per day, yet they typically keep 40 or 50 gallons (often times more) of water hot 24 hours a day. Having a system that eliminates the storage and heats water only as you use it can dramatically reduce your energy consumption. Click Here to see some example of energy savings.

Tankless Water Heater Buyer's Guide:
Our Buyer's Guide will give you a goof overview on how tankless water heaters work, why they will save you money, and general sizing and installation information. For more detailed information click on any of the section links listed below:

Section Links:
Tankless Water Heater Frequently Asked Questions
Tankless Water Heater Installation Guide
Tankless Water Heater Sizing Guide
Tankless Water Heater Energy Saving Information
Gas Tankless Water Heater Comparison Chart
Electric Tankless Water Heater Comparison Chart

I. Tankless Water Heaters: An Overview:
Most people in North America currently use a storage tank water heater to provide hot water in their homes. A storage tank water heater keeps water hot 24 hours a day, even while you are at work or sleeping. A tankless water heater, on the other hand, does not store hot water. It heats the water as you use it.

How does this work? When you open a faucet, the flow of the water triggers the heater to turn on. Whether you use gas or electricity, the powerful gas burners or electrical elements will turn on, rapidly heating the water as it passes through the unit. The water is heated instantly, and the time it takes to obtain hot water is directly related to the distance the hot water has to travel from the water heater to where hot water is being used. The burners or elements then shut down when you shut off the hot water. The energy that is consumed is only for the hot water that is being used which is why tankless water heater can save you a substantial amount of money off of yoru electricity bills.

Depending on which model of tankless water heater you purchase, and what size storage tank you have now, and if it runs on gas or electricity, you could save anywhere from 5% to 69% off your hot water heating bill. How? Most homes use hot water for a cumulative total of about one hour per day, yet they typically keep 40 or 50 gallons (often times more) of water hot 24 hours a day. Having a system that eliminates the storage and heats water only as you use it can dramatically reduce your energy consumption. Click Here to see some example of energy savings.



There are many advantages of having a tankless water heater in your home besides the money savings. A tankless water heater:
- Is very small and can hang on the wall, thereby saving you valuable floor space.
- Is designed with replaceable parts and is built with such materials as copper, stainless steel, and aluminum so as to last a lifetime. Energy savings is only one segment of savings?with proper care this could be the only water heater one needs in a lifetime.
- Is almost entirely recyclable, so if you ever decide to replace it, it doesn?t have to go to the landfill.
- Will not develop a corrosive leak like a storage tank water heater, saving you from expensive water damage in your home. Note: A tankless water heater can leak if it is exposed to freezing temperatures or has a manufacturing defect.
- Maintains its efficiency throughout the lifetime of the unit. Storage tank water heaters decrease in efficiency over time due to mineral build-up inside the tank. This is due to the fact that storage tank water heaters store hot water, giving those minerals a chance to settle out and bake from the heat onto the walls of the tank, and onto the heating element in electric models, thereby reducing heattransfer.

II. Sizing Your Tankless Water Heater
Tankless water heaters are rated by 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 remote application, such as just a bathroom) in your home. It is important to note that you should never try and save money by undersizing your tankless water heater.

Determine the maximum number of devices you want to run and their total flow rate. Then, add up their flow rates (gallons per minute). This is the desired flow rate you'll want for the demand water heater. For example, let's say you expect to simultaneously run a hot water faucet with a flow rate of 0.75 gallons per minute and a shower head with a flow rate of 2.6 gallons per minute. The flow rate through the demand water heater would need to be at least 3.26 gallons per minute. To reduce flow rates, install low-flow water fixtures.

Determine required temperature rise. To determine temperature rise, subtract the incoming water temperature from the desired output temperature. Unless you know otherwise, assume that the incoming water temperature is 50ºF (By using a low temperature assumption you ensure that you will not undersize your tankless unit. If you live in a warm climate your water temperature will likely be much higher.) For most uses, you'll want your water heated to around 105 - 115 degrees. In this example, you'd need a demand water heater that produces a temperature rise of 55 degrees.

Once you have determined what your GPM rate is (how many applications you want to run at once) and the desired temperature for each application you can then view our product listings to make sure you have a model that has ample power. Click Here to view a quick comparison chart comparing the power of each of the models we sell. Gas tankless water heaters are more efficient and more powerful on whole than their electric counterparts.

Flow Rates
How much hot water do you need at one time?   Do you need to run 2 showers at the same time or maybe a shower and a couple sinks?  The chart below shows the range of water usage range and average water temperatures for various fixtures.  We suggest using 2.5 gpm for a shower and 1.0 gpm for a bathroom as a reference point in determining your total simultaneous water needs.
 

Fixture Average Flow GPM Avg. Temp. Tub 4.0 102 F Shower 2.5 - 3.0 104 F Washing Machine 2.0 120 F Dishwasher 1.5 110 F Kitchen Sink 1.5 110 F

For example, if you are running 2 showers at the same time, you will need 5 gallons of hot water per minute from the tankless water heater.  If you were running a shower and the washing machine at the same time, you would need 4.5 gallons per minute from the water heater.  In either of these situations, you will want to size the unit that meets or exceeds how much hot water you need at the same time.

Note: tankless water heaters are intended to heat potable (drinking) water only and the inlet water to a tankless unit should not be pre-heated.

III. Installation - Gas, Electric, Outdoor, and Point Of Use Installation Overview

Gas Installation
Gas tankless water heaters require more installation than their electric counterparts. We have summarized some installation information for both types below. We always recommend that you provide your gas company or installation professional a copy of the installation manual before making your purchasing decision.

Do I have the correct gas connection coming into my house and do I have enough gas power to run the tankless water heater I purchase? If you contact your local gas company or installation professional they can determine whether you have enough gas coming into your house to power a tankless water heater. You should always refer to the Installation Guides we provide in order to ensure proper installation.

Ventilation: All Indoor gas tankless water heaters must vent the excess warm air they create. They can either vent horizonal up through a chimney or roof pitch or vertically through a side wall. Some units can only vent horizontally, some vertically, and some units can vent either way. You will want to know what options you have for venting before you make a decision on which gas tankless water heater may be right for you. We hav included pictures these venting methods below:

Combustion Air:
Tankless water heaters require combustion air. It's important to understand how combustion air will be delivered to your water heater and how much combustion air is needed. When placed in an unconfined area, combustion air can simply be the air within your home. Confined areas (such as a closet) may require air ducts or additional air inlets. Whenever possible, it is always better to pull combustion air in from outside the home - it is cleaner and will keep your tankless water heater operating at peak performance. Check the installation manual for more information about combustion air requirements.

Electric Tankless Water Heater Installation
Many people that do not have the power needs for a gas tankless water heater or who cannot vent a gas model will opt for an electric model because they do not require any type of venting. Electric models, do however, require substantial energy requirements. We have provided links to installation manuals for all Bosch whole house electric tankless water heaters we sell below:

The size of your breaker box and how many amps you have available is the most important thing to consider when purchasing an electric water heater. Depending on which electric tankless water heater best fits your home needs, the required amps will be 150 or 200 amps. If you don't meet the amperage requirements stated in the installation manual, how do you plan to adapt? Some home owners choose to add an additional breaker box to their existing wiring while others will replace their existing breaker boxes with bigger ones. Talk to an electrician or installer before taking the next step in buying an electric water heater to be sure you'll be ready to put it to use in your home.

Outdoor Model Installation
Outdoor tankless water heaters may be a good alternative for you if you are not able to vent a traditional gas model. You will need to consult the owner's manual of the outdoor model you are interested in to see what type of clearances are required for the outdoor installation. See the diagram below for an example of an outdoor installation