The type of water heater you select in your home impacts your comfort, energy bill, and the maintenance cost in the long term. Tankless water heaters have gained popularity throughout metro Atlanta for their efficiency and endless hot water supply. However, when you begin researching the tankless models, you soon come to two different models: condensing and non-condensing models.
The distinction between these systems can also assist you in making a sound decision that fits your home requirements, budget, and current infrastructure. The two kinds offer on-demand hot water, which does not require storage tanks, though they are different in operation and have their own pros and cons.
This guide breaks down everything you need to know about condensing and non-condensing tankless water heaters. You will understand the functionality of each system and its pros and cons, and which one would be the most reasonable to use in your case.
What Is a Tankless Water Heater?
Tankless water heaters, also called on-demand or instantaneous water heaters, heat water only when you need it. Tankless units turn on like a hot water tap, unlike the traditional tank systems that heat and hold 40 to 80 gallons of water throughout.
As you open up a hot water faucet, the cold water enters via a pipe to the tankless water heater. The water is passed through a heat exchanger where it is heated up by a gas burner or an electric element. The hot water is then passed straight to your tap, shower, or appliance. This process provides an unlimited supply of hot water as opposed to a storage tank.
Tankless water heaters offer several advantages over traditional tank systems. They also offer unlimited hot water, hence they never claim exhaustion when one is on a long shower or when more than one fixture runs at a time. They take little space and are placed on walls and leaving room. The power consumption is often energy saving on the fact that you do not waste power on standby heat loss to maintain a tank of water at a constant temperature.
How Does a Tankless Water Heater Work?
Knowing how tankless systems work in principle makes you thankful for the variations of condensing and non-condensing systems.
The process of heating starts once the flow sensor detects the water flow through the unit. This sensor alerts the control board to turn the gas burner on or the electric heating elements on. The heat exchanger is a series of coils or tubes of water, which is heated by the burner or elements.
Cold water is directed to the heat exchanger, where it takes on the heat and attains your desired temperature. A temperature sensor will be used to monitor outgoing water temperature to ensure the same output by adjusting the intensity of the burner. This modulation guarantees that you get water at the desired temperature, despite changes in the flow rate.
Gas tankless water heaters use powerful burners that can produce 150,000 to 200,000 BTUs or more. This is attributed to the high heat production, which allows the system to produce water quickly as it passes through. The process of combustion is accompanied by exhaust gases that need to be pumped out of your house.
The flow rate is what will dictate the amount of hot water that a tankless unit can provide. Both models have a maximum flow rate that is expressed in gallons per minute(GPM). An average shower consumes 2 to 2.5 GPM, and a washing machine may have 2 GPM. Your tankless heater should be able to supply enough flow to use at the same time in your home.
Temperature rise is the difference between the incoming cold water temperature and the necessary hot water temperature. The average temperature of incoming water in Georgia is 60 to 70. It would take a 50 to 60 degree temperature increase to heat it to 120 degrees. An increase in temperature decreases the maximum flow rate that a unit can give.
The method of water flow continues with exhaust gases escaping through the venting system after they have gone through the heat exchanger. This is where condensing and non-condensing tankless water heaters differ significantly in their operation and efficiency.
Non-Condensing Tankless Water Heaters
Non-condensing tankless water heaters represent the traditional design that has been used for decades. They are less efficient and simpler to construct compared to condensing models.
How Does a Non-Condensing Tankless Water Heater Work?
Non-condensing plants heat water using only one heat exchanger. The exchanger is heated using gas burners, and the heat is collected by the water passing through the absorber. The exhaust gases are given off at temperatures of approximately 300-500°F during the combustion process.
These hot exhaust gases leave the unit and flow directly outside using special venting materials. Due to the high exhaust temperatures, non-condensing units need to use stainless steel or other high-temperature venting materials. Normal PVC pipe is unable to sustain such temperatures, and it would melt/degrade.
High exhaust temperature signifies wastage of energy. The heat that leaves via the vent is the energy that you have paid for but never utilized in heating water. This renders non-condensing units inefficient as compared to condensing models, which are normally 80 to 85 percent efficient in energy.
Installation of the water heater vent in non-condensing units must be done with close attention to materials and clearances. The vent should have the right distances between the vent and combustible substances, windows, and air intakes. Professional water heater installation services ensure venting meets code requirements and operates safely.
What are the Benefits of Non-Condensing Water Heaters?
Non-condensing tankless water heaters offer several advantages that make them appropriate for certain situations.
Non-condensing units are less expensive in the initial investment. These systems incur lower prices of about 500-1000 dollars as compared to similar condensing systems. This is a big difference for homeowners with a tight budget.
A simple design translates to fewer parts that may go wrong. Simple units are non-condensing and are only constructed with one heat exchanger and simple controls. Such simplicity can be converted to simpler repairs and even reduced maintenance expenses.
The small size of the physical dimension enables it to be installed in smaller spaces. In non-condensing units, the secondary heat exchanger and condensate management system are not needed, and hence the unit remains smaller. This is important in houses with limited installation space.
Proven technology implies decades of experience and development in the field. Non-condensing tankless water heaters have been used successfully for many years. Technicians know how to operate and repair them.
There are no condensate drainage requirements that make installation complex. Condensing units generate acidic condensate, which has to be neutralized and evacuated. This complication is not encountered in non-condensing units, and therefore, the installation of tankless heaters could be slightly easier in houses with inappropriate drainage.
Condensing Tankless Water Heaters
Condensing tankless water heaters represent newer, more efficient technology that captures and uses the heat that non-condensing units waste.
How Does a Condensing Tankless Water Heater Work?
Condensing tankless water heaters use two heat exchangers instead of one. The main heat exchanger is similar to the exchanger in non-condensing units, where heat in burner flames is transferred to water in the system.
The secondary heat exchanger absorbs the heat of exhaust gases, and then they are vented out of the unit. These gases, which still have notable thermal energy, proceed to the secondary exchanger, where other cold water takes in this extra heat.
As the exhaust gases cool in the secondary heat exchanger, liquid is formed by condensing water vapor in the gases. The resultant condensation gives out latent heat that further increases the temperature of the starting water. This process of condensing to recover wasted energy is called condensing.
When exhaust gases leave a condensing unit, the temperature of the exhaust gases is approximately 100 to 120 degrees Fahrenheit. Such a drastic drop in temperature indicated that a lot more heat remained in your water and was not being wasted through the vent.
The reduced exhaust temperatures enable the use of PVC or CPVC venting material, which is cheaper than the stainless steel that is used in non-condensing units. This partially counterbalances the increased equipment price of condensing models.
The condensation process yields acidic water, which has to be taken care of. Drains. The unit empties into a special drain line. In selected jurisdictions, condensate neutralizers are required to increase the pH level of the condensate before it finds its way into the drainage systems. Correct installation of the hot water system involves proper management of the condensates.
What are The Benefits of Condensing Water Heaters?
Condensing tankless water heaters deliver advantages that often justify their higher initial cost.
Superior energy efficiency is 90 to 98% which is much higher than the non-condensing models. This efficiency has direct effects of decreasing natural gas use and decreasing utility bills. The additional initial cost can be surpassed by the energy savings over the 20-year life of the unit.
The decreased cost of operation is due to less consumption of fuel. Condensing units utilize about 10 percent to 15 percent of the amount of gas that is required by non-condensing units in the climate of Georgia, where the temperature of incoming water is moderate. This is a saving that accrues with years of operation.
Less energy consumption results in environmental benefits. Less natural gas will lead to decreased carbon emissions and fewer environmental effects. This is important to the eco-conscious householder.
Reduced vent temperatures enhance safety and minimize clearance. Less cooler exhaust would result in burns or ignition of nearby materials. Certain types of condensing units have shorter vent runs that run through sidewalls, and this offers flexibility in the installation.
Elastic venting systems based on PVC lower installation expenses. Compared to stainless steel, PVC venting is much cheaper and easier to operate within tankless water heater installation projects. This will save a number of hundreds of dollars in installation.
The possible rebates and incentives offset an increase in equipment prices. Rebates are available in most utility companies and government programs on high-efficiency condensing water heaters. These incentives are able to narrow the price difference between condensing and non-condensing models.
Condensing vs Non-Condensing Tankless Water Heaters
| Factor | Condensing Tankless Water Heaters | Non-Condensing Tankless Water Heaters |
| Efficiency | Very high (90–98%) | Lower (80–85%) |
| Energy Savings | Saves 10–15% more energy long-term | Higher energy use |
| Initial Cost | Higher unit cost, lower venting cost | $500–$1,500 cheaper upfront |
| Operating Cost | Lower; saves $50–$150 per year | Higher yearly energy cost |
| Lifetime Savings | $1,000–$3,000 over 20 years | Minimal long-term savings |
| Venting Requirements | Uses PVC; flexible and cheaper | Needs stainless/high-temp venting |
| Installation Complexity | Slightly complex (needs condensate drain) | Simpler installation |
| Maintenance | Similar, includes condensate system care | Similar routine maintenance |
| Size & Space | Slightly larger | More compact |
| Environmental Impact | More eco-friendly, lower emissions | Higher energy consumption |
What Is Better: Condensing or Non-Condensing Tankless Water Heater?
The more appropriate one is based on the circumstances, priorities, and home attributes.
Condensing tankless water heaters make the most sense for most homeowners. The high efficiency, reduced operating expenses, and a variety of venting choices are long-term value-added that supersede high initial costs. The extra investment will be recouped by the energy savings in case you intend to remain longer in your home.
Change to a condensing unit in case you are more concerned with energy consumption and environmental friendliness. The 10-15 percent energy saving is real and has an effect on the utility bills and energy usage. The value is further enhanced by the rebates and incentives that are frequently offered on models of high efficiency.
Condensing models are best implemented in cases where the venting alternatives are restricted. Installation problems in certain houses are solved by the capability to utilize PVC venting with reduced length of the runs and more adaptable routing. When the house does not have convenient exit vents to carry the hot exhaust, then the condensing units are probably the only viable choice.
Non-condensing tankless water heaters make sense in specific situations. Non-condensing units are cheaper with the benefits of tankless at a lower price, in case your main requirement is low initial investment, and you need to keep it at a low upfront cost. The technology is well-tested and trusted and provides decades of service.
Select non-condensing units in case of very little space to install. The smaller size can fit in smaller places where condensing models may not fit. This is important in little utility rooms or narrow mechanical rooms.
Non-condensing models are suitable in vacation houses or those houses that have low consumption of hot water. With less hot water usage, the performance benefit of condensing units generates reduced absolute savings. In such cases, the cheaper equipment cost can be more appropriate.
Take your local weather and the water temperature. The required temperature increase is moderate in Georgia, where incoming water is rather warm. This allows the two types to perform. In lower temperatures, when the incoming water is cold, the efficiency advantage of condensing units is further increased.
Check on the available rebates and incentives within your location. Federal tax rebates, utility company rebates, and state incentives have the ability to lower the effective cost of condensing units. Verify the existing programs prior to your decision-making.
Conclusion
Understanding the difference between condensing and non-condensing tankless water heaters empowers you to make the right choice for your home. At relatively high initial costs, condensing units are more efficient, less expensive to operate, and can be vented flexibly. Non-condensing models offer established performance and reduced initial capital expenditure at the expense of a little more energy.
For most homeowners in metro Atlanta, condensing tankless water heaters deliver the best long-term value. The extra investment will be justified by the imparted energy saving, environmental benefits, and installation flexibility. Non-condensing units, however, are also suitable where they are more convenient due to budget limitations or other installation conditions.
Whichever type of one you pick, they can be professionally installed and maintained to give maximum performance and life. Adequate installation of venting in water heaters, proper size, and proper installation are essential to safety and efficiency.
Top Tech Mechanical specializes in the installation service of tankless water heaters with over 15 years of experience in the same area within metro Atlanta. Our qualified technicians know about the condensing and non-condensing systems and will assist you in choosing the appropriate one based on the needs and financial possibilities of your house.
We provide comprehensive hot water system installation services, from initial assessment and equipment selection through professional tankless water heater installation and ongoing tankless water heater maintenance service. We address all details of the project, venting, gas lines, condensate drainage, and system commissioning.
Whether you need new tankless heater installation, commercial water heater repair, or routine maintenance, Top Tech Mechanical delivers the quality workmanship and customer service you deserve. Our HVAC and plumbing services are reliable and professional to serve the communities of Kennesaw, Woodstock, Acworth, and others.
Call Contact Top Tech Mechanical and talk about your water heating requirements, and book an appointment. And allow our experience and devotion to excellence to serve you up indefinite hot water, higher efficiency, and sure performance for many years to come.