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What You Need to Know Before You Buy
How much hot water do you use in your home?
Our top models will handle up to two major applications at once, such as a dishwasher and washing machine or two showers running at the same time. The best tankless water heaters will pump out 5-6 gallons per minute, or over 300 gallons per hour - and you never run out. An extra-large capacity 80 gallon tank water heater runs dry in about 15 minutes by comparison.
The trouble with extra-large tank heaters is that whether or not you use the 80 gallons of water stored inside, you pay a high price to keep it hot 24 hours a day. Imagine leaving your car running 24 hours a day!
Once you’ve settled on a heater that will meet your hot water demands while saving you money, you’ll need to carefully consider how it will work within your home.
Gas Tankless Water Heaters
8 things you’ll need to consider before buying your tankless water heater:
8 things you’ll need to consider before buying your tankless water heater:
1.The appropriate size for your household needs
Above all, anyone buying a tankless unit needs to think about how they use the water in their home—during peak water usage times, how many faucets, shower heads, bath tubs, washing machines, dishwashers and jacuzzis will you be running at once? Tankless water heaters provide endless hot water for up to two major applications at a time and up to 3-4 sinks at a time.
Above all, anyone buying a tankless unit needs to think about how they use the water in their home—during peak water usage times, how many faucets, shower heads, bath tubs, washing machines, dishwashers and jacuzzis will you be running at once? Tankless water heaters provide endless hot water for up to two major applications at a time and up to 3-4 sinks at a time.
2.Minimum flow rate
Tankless water heaters require a minimum flow of water—typically around a half gallon per minute—through the heating system to heat water. To ensure your tankless water heater will deliver enough hot water, determine the flow rate and temperature rise you'll need. Make sure the unit you purchase can deliver the most common temperature rise of 70 degrees Fahrenheit (39 degrees Celsius) at the desired flow rate. To avoid problems associated with not meeting the minimum flow requirement, consult with a qualified plumber to make sure the flow rates at outlets you’ll connect to the heater exceed the unit’s minimum requirements.
Tankless water heaters require a minimum flow of water—typically around a half gallon per minute—through the heating system to heat water. To ensure your tankless water heater will deliver enough hot water, determine the flow rate and temperature rise you'll need. Make sure the unit you purchase can deliver the most common temperature rise of 70 degrees Fahrenheit (39 degrees Celsius) at the desired flow rate. To avoid problems associated with not meeting the minimum flow requirement, consult with a qualified plumber to make sure the flow rates at outlets you’ll connect to the heater exceed the unit’s minimum requirements.
3.Gas sizing information
Take a look at the installation manual of the product you’d like to purchase to see the gas sizing requirements. Tankless water heaters utilize three to four times the BTUs of a conventional tank water heater. Ask your plumber to verify that your current gas line, size and length can provide sufficient gas flow to the unit. Consult with your gas company to determine if your gas meter is adequately able to accommodate larger water heaters.
Take a look at the installation manual of the product you’d like to purchase to see the gas sizing requirements. Tankless water heaters utilize three to four times the BTUs of a conventional tank water heater. Ask your plumber to verify that your current gas line, size and length can provide sufficient gas flow to the unit. Consult with your gas company to determine if your gas meter is adequately able to accommodate larger water heaters.
4.Compatibility with water supplies
Local water quality should be considered in areas where the potential for scaling may be increased. Scale control in water heaters requires disconnecting the unit, connecting deliming hoses and recirculating special deliming agents.
Local water quality should be considered in areas where the potential for scaling may be increased. Scale control in water heaters requires disconnecting the unit, connecting deliming hoses and recirculating special deliming agents.
5.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.
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.
6.Clearances
Tankless water heater placement is another important factor to consider. Each tankless water heater will have different distance requirements between the heater and other parts of your home, as seen in the example above.
Some of the clearances you’ll need to consider are:
- Operable windows, doors and other fresh air openings
- Adjacent walls or tall bushes
- Below gutters, sanitary pipework, eaves or overhangs
- Distance above the ground
- From a gas meter, gas regulator, electrical box or another heater
Check the installation manual to see what your heater requires and whether it will work with your home layout.
Tankless water heater placement is another important factor to consider. Each tankless water heater will have different distance requirements between the heater and other parts of your home, as seen in the example above.
Some of the clearances you’ll need to consider are:
- Operable windows, doors and other fresh air openings
- Adjacent walls or tall bushes
- Below gutters, sanitary pipework, eaves or overhangs
- Distance above the ground
- From a gas meter, gas regulator, electrical box or another heater
Check the installation manual to see what your heater requires and whether it will work with your home layout.
7.Installation issues need to be considered
Special venting and/or the need for increased combustion air may require additional changes because of the unit’s higher input rates. You will also need 120 volt electric power, and in the event of an electrical power outage, the tankless water heater will not operate.
Special venting and/or the need for increased combustion air may require additional changes because of the unit’s higher input rates. You will also need 120 volt electric power, and in the event of an electrical power outage, the tankless water heater will not operate.
8.Venting
Tankless water heaters require gas exhaust venting to the outside. Some vent horizontally, others vent vertically. Check the installation manual for more information about venting options and for any accessories you’ll need to buy for your chosen venting configuration.
All manufacturers of stainless steel products state that the installer cannot mix and match venting. It is a liability issue. If you start with one brand of stainless steel venting, you must complete the job with the same brand. You cannot mix and match venting. If you do all matters of warranty will be voided.
Tankless water heaters require gas exhaust venting to the outside. Some vent horizontally, others vent vertically. Check the installation manual for more information about venting options and for any accessories you’ll need to buy for your chosen venting configuration.
All manufacturers of stainless steel products state that the installer cannot mix and match venting. It is a liability issue. If you start with one brand of stainless steel venting, you must complete the job with the same brand. You cannot mix and match venting. If you do all matters of warranty will be voided.
Electric Tankless Water Heaters
There are two things to consider before buying an electric tankless water heater.
There are two things to consider before buying an electric tankless water heater.
1.Power Requirements
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.
AE115 Minimum
150 Amp Service
Requires two independent 240V AC circuits protected by two separate and independent double pole breakers.
AE125 Minimum
200 Amp Service
Requires three independent 240V AC circuits protected by two separate and independent double pole breakers.
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.
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.
AE115 Minimum
150 Amp Service
Requires two independent 240V AC circuits protected by two separate and independent double pole breakers.
AE125 Minimum
200 Amp Service
Requires three independent 240V AC circuits protected by two separate and independent double pole breakers.
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.
2.Inlet Water Temperature
The inlet water temperature of your location will help to determine the correct model for you. The AE115 is recommended for no lower than 55 degree inlet water temperature year round while the AE125 is recommended at 45 degrees.
The inlet water temperature of your location will help to determine the correct model for you. The AE115 is recommended for no lower than 55 degree inlet water temperature year round while the AE125 is recommended at 45 degrees.
NOTE: CPO recommends that appliances be installed by a licensed professional.
