Best GAS Tankless Water Heater for your Home

If you are considering a tankless GAS water heater, sometimes called an inline water heater, in your comparison shopping, we presume you have access to natural gas as an energy source to your home.

To evaluate which is the best gas tankless for you, you want to decide which demand-type you are looking for. Typically you want a high-demand (10 Gallons Per Minute) type if you want hot water for four bathrooms. If yow want hot water supply to two and a half bathrooms, a medium demand (6.6 GPM) is your demand type.

You guess it right – there isn’t one tankless that is best for all households. The best unit is the one that meets your on-demand water needs.

There are two types of indoor Tankless gas water heaters: condensing and non-condensing. Condensing models generally require lower temperature venting than non-condensing models.

Our top-rated condensing tankless gas condensing water heaters:

High Demand: Takagi T-H3-DV-N Condensing High Efficiency Natural Gas Indoor Tankless Water Heater

Model: Takagi T-H3-DV-N Condensing High Efficiency Natural Gas Indoor Tankless Water Heater (note: there is also a Takagi T-H3-DV-P model that utilizes propane and has the same specs).
Dimensions: H-22.5”, W- 17.75″, D-10.75”
Weight: 59 lb.
Flow rate: 10 GPM. It can produce sufficient hot water for a large house, including multiple bath rooms and other appliances
Demand type: High-demand, Condensing, most suitable for high-occupancy of 3-4 bathrooms household, or commercial application.
Application: Single point-of-use or multiple applications

With its 10 GPM flow, the T-H3-DV-N is especially well suited for higher demand residential of smaller commercial applications. It has sufficient capacity to be used for such applications as space heating or recirculating hot water systems. This unit complies with Ultra-Low NOx regulations now common in building codes, meaning it is low polluting and highly efficient.

This unit can typically supply 3-4 simultaneous showers, depending on inlet water temperature.

This natural gas tankless water heater is quality-built using commercial grade copper alloy for the primary heat exchanger tubing. The secondary heat exchanger utilizes 316L stainless steel for better corrosion resistance.

The T-H3 is also suitable for heavier residential usages such as space heating or domestic recirculation systems. Certified up to 10,100 ft. altitude.

PROs:

• Extremely low energy use, with two-stage heat exchanger, minimizes pollution and allows easy, low-temperature venting while minimizing operating expense.
• ENERGY STAR® qualified.
• Complies with Ultra-Low NOx regulations of less than 14 ng/J (<20ppm).
• High 10 GPM flow rate will provide hot water to almost any residence—up to 4 showers at once.
• Multiple units can be linked together for even higher flow-rate applications. Easy-Link up to four units or Multi-Link up to 20 units with a Multi-Unit Controller.
• Venting with Schedule 40 PVC, CPVC, PP, Category III stainless steel—easy to install and low temperature.
• Safety features include freeze, overheat, surge protection, and troubleshooting diagnostic codes.
• 15-year limited heat exchanger, 5 yrs limited parts Residential use.
• 5-year limited heat exchanger, 5 yrs limited parts Commercial use.
• NSF certified for commercial applications.

CON:

• For most residential uses, this is a centralized, single-point solution (as are most higher capacity gas tankless water heaters), so while it will provide “endless” hot water, there will still be a lag getting hot water to any given use point of use depending on the length of pipe between the water heater and, e.g., the shower.

Summary

This Takagi tankless water heater provides a very high flow rate sufficient for almost any house and smaller businesses. It is relatively inexpensive to operate because of being a condensing model, utilizing a two stage heat exchanger. The warrantees are very good on the product. With the high-quality materials, the Takagi T-H3-DV-N (or its propane sibling) should provide you with ample hot water for a long time.

High Demand: Rinnai RUC98iN Ultra Series Natural Gas Condensing Tankless Water Heater

Model: Rinnai RUC98iN Ultra Series Natural Gas Condensing Tankless Water Heater
Dimensions: 10 x 18.5 x 26 inches
Weight: 82 lb
Flow rate: 9.8 GPM. Allows this natural gas unit to produce a sufficient flow of hot water for a large house, including multiple bath rooms and other appliances
Demand type: High-demand, condensing, most suitable for high-occupancy with 3-4 bathroom households or commercial application.
Application: Single point-of-use or multiple applications

One of Rinnai’s most efficient indoor tankless water heaters, this model features condensing technology which yields an Energy Factor of .95 (Uniform Energy Factor of .92).

With a high rated flow of 9.8 GPM flow, the RUC98iN is very well suited for higher demand residential of smaller commercial applications. If you have a large house or family, this Rinnai tankless water heater is certainly a model you should consider. In addition to providing hot water for showers, laundry, and a dishwasher, it has sufficient capacity to be used for other applications as space heating or recirculating hot water systems.

This unit complies with Ultra-Low NOx regulations now common in building codes, indicating low pollution and high efficiency.

This unit can typically supply 3-4 simultaneous showers, depending on inlet water temperature.

The T-H3 is also suitable for heavier residential usages such as space heating or domestic recirculation systems. Certified up to 10,100 ft. altitude.

PROs:

• Extremely low energy use, condensing design with two-stage heat exchanger, minimizes pollution and allows easy, low-temperature venting while minimizing operating expense.
• ENERGY STAR® qualified.
• Complies with Ultra-Low NOx standards.
• High 9.8 GPM flow rate will provide hot water to almost any residence—up to 4 showers at once.
• MC-91-2US controller included.
• Accessories available for rack-mounting multiple units and for ganging the exhausts of multiple units.
• Warranty: Residential: Limited 12-year on heat exchanger, 5-year on parts, 1-year on labor (5-year optional on labor). Commercial: Limited 5-year on heat exchanger, 5-year on parts, 1-year on labor (2-year optional on labor)
• Top rated by Amazon based on customer reviews.

CON:

• For most residential uses, this would be used in a centralized, single-point solution (as are most high-capacity gas tankless water heaters. It would provide “endless” hot water to your house, but there would still be a lag getting hot water to any given use point of use depending on the length of pipe between the water heater and the point of us (e.g., shower).

Summary

This Rinnai tankless water heater provides a sufficiently high flow rate for almost any house or smaller business. As a high-efficiency condensing model, it is relatively inexpensive to operate. It utilizes a two stage heat exchanger. The warrantee on this Rinnai unit is very good. With the consistently excellent customer reviews, the Rinnai RUC98iN Ultra Series should provide you with satisfaction and ample hot water for a very long time.

Medium Demand: Noritz NRC661-DV-NG Indoor Condensing Direct Tankless gas water heater

Model: Noritz NRC661-DV-NG Indoor Condensing Direct Tankless gas water heater
Dimensions: 20.5” (H) x 13.8” (W) x 6.7” (D)
Weight: 39 pounds
Flow rate: 6.6 GPM.
Demand type: Medium-demand, condensing, most suitable for homes with 1-2 bathrooms.
Application: Single point-of-use or multiple point applications; medium sized residential usage.
Note: This same water heater, and many other Noritz water heaters, is also available as a propane gas tankless water heater and as an outdoor tankless water heater.

Noritz and introduced the first electronically controlled, modern tankless water heaters nearly 40 years ago, and Noritz has remained an innovator in the water heating solutions. Noritz has great products for both residential and commercial markets.

A number of Noritz tankless water heaters are specifically optimized as replacements for existing storage tank water heaters, so we strongly suggest you consider Noritz when your goal is to replace a storage tank water heater with a tankless unit.

This Noritz NRC661 gas tankless water heater is a high-efficiency condensing model, being that has both primary and secondary heat exchanger to recover the most possible energy to eat your water. As noted, this this unit comes in both natural gas and propane versions. Both are quite efficient (.93 EF for Propane and .91 EF for Natural Gas).

PROs:

• Noritz invented the category and has extensive experience in tankless water heaters
• Energy STAR rated
• Environmentally friendly, low NOx emissions
• Direct electronic ignitions—no pilot light to waste energy
• Controls include built in display able to set the output temperature to 120°F, 135°F, or 140°F
• Warranty: 12 years (heat exchanger), 5 years parts, 1 year labor
• Requires only ½” gas line
• Easy venting with PVC pipe
• Temperature Lockout, High Elevation Adjustment
• Key safety features- Flame Sensor, Overheat Prevention Device, Lighting Protection Device, Freeze Protection, Condensate Overfill, Fan Rotation Detector
• Supplied with a 120 volt power cord (indoor models only)

CON:

• Common to centralized water heaters, while providing endless hot water, this unit does not eliminate the “cold sandwich” of cold water between the heater and the point of use (e.g., shower) when the hot water is first turned on.

Tips for maintenance:

• Periodically check and clean the air intake filter
• Visually inspect the system for any signs of damage or leaks
• Periodically flush the heat exchanger to remove any scale

Summary

This Noritz NRC661 tankless gas water heater comes from one of the oldest and most experienced manufacturers of tankless water heaters. It is feature rich and high quality. It provides a moderate flow of hot water sufficient for medium-sized homes. Being tankless, it can provide and endless flow of hot water for moderately sized homes.

You should consider this model if it meets your flow requirements.

Best Seller: Rheem RTGH-95DVLN Indoor Condensing Direct Vent Gas Tankless water heater

Model: Rheem RTGH-95DVLN Indoor Condensing Direct Vent Gas Tankless water heater
Dimensions: H-27.5”, W-18.5”, D-9.75” (D)
Weight: 79 pounds
Flow rate: 9.5 GPM.
Demand type: High-demand, most suitable for larger homes up to 4 bathrooms.
Application: Single point-of-use or multiple point applications; residential and small commercial usage.

• Rheem is one of the most popular and well respected brands in the U.S. and Canada. This model is an Amazon Best Seller and is highly rated by purchasers.
• Top quality, reliable products with a 12 year limited warranty.
• Excellent customer support.

This Rheem RTGH-95DVLN gas tankless water heater is super high efficiency while having a flow rate of 9.5 GPM that should meet your whole house water needs. Because it is a tankless water heater, it provides an endless supply of hot water for up to four bathrooms at once. Because it combines high-efficiency with its tankless design, it can save you a lot of money on your natural gas bill. Its Best-Seller status speaks for itself as a reliable and cost-efficient solution to your water heating needs.

PROs:

• Digital display shows temperature setting and maintenance codes
• Two-pipe direct vent system designed for PVC pipe
• Built-in electric blower
• Self-diagnostic system for easy installation and service
• Digital remote control and 10 ft. of thermostat wire included
• Exclusive! Guardian overheat film wrap (OFW) helps ensure water heater will not overheat
• Can utilize multiple units at once for greater capacity using the EZ-Link cable (2 units) or with optional control units to manifold up to 20 units.
• High-altitude capability – works reliably up to 9,840 ft. elevation
• Freeze protection to -30°F
• Supplied with a 120 volt power cord (indoor models only)

CON:

• This Rheem tankless water heater may require you to move your water lines to accommodate connections at the bottom rather than at the top (as with most residential storage tank water heaters). This should not be difficult for your installer.

Tips for installations:

• You want to hire a licensed contractor to properly install this unit.

Tips for maintenance:

• Periodically check and clean the air intake filter
• Visually inspect the system for any signs of damage or leaks
• Periodically flush the heat exchanger to remove any scale. Here’s a service valve kit useful for your annual maintenance:
Sale

Rheem RTG20220AB Webstone Tankless Water Heater...
• Webstone service valves
• Includes relief valve
• These hot and cold water service valves simplify installation and service by combining multiple valves and connections...
• Clean brass for California low lead codes
$114.54 −$9.55 $104.99
View on Amazon

This Rheem service valve kit is designed to fit a variety of Rheem tankless water heaters, including the Rheem RTGH-95DVLN.

Generally, you will want to insert a service valve between the cold-water input line and your tankless water heater and, between the hot water output line and your tankless unit.

This kit serves several purposes, including allowing an annual flush of your tankless water heater to purge any scale that has built up inside your water heater. These multi-position valves allow you to open or close the water flow between your pipes and the water heater and allow you to drain remaining water from your heater for service.

This service valve also includes a pressure relief valve.

Summary

This Rheem tankless water heater is an Amazon best seller for a reason. It has sufficient flow rate to meet your hot water needs for your entire house. Rheem is a well-known and well-respected brand and this unit has a great warranty. You will appreciate the endless supply of hot water and the precise temperature control available. Not having to keep stored water hot will also provide you with important economic and environmental advantages. Many customers have recognized this unit as a great solution for a whole house gas tankless water heater.

Our top-rated non-condensing gas tankless water heaters:

High Demand: Rinnai RL94iN Natural Gas non-Condensing Indoor Tankless Water Heater

Model: Rinnai RL94iN Natural Gas non-Condensing Tankless Water Heater
Dimensions: 9.3” x 14” x 23”
Weight: 50 lb
Flow rate: 9.4 GPM.
Demand type: High-demand, most suitable for high-occupancy of 3 bathrooms household, or commercial application
Application: Single point-of-use or multiple applications; residential and commercial usage.

Rinnai has been the number one selling brand tankless gas heaters in North America for years. Rinnai brand is reputable for having:

• Top quality and reliable products. The life expectancy of a Rinnai tankless is up to 20 years.
• Excellent customer support. Rinnai has an in-house support 24/7 every day of the year, including holidays.
• Excellent product warranty. For the residential Installations, Rinnai provides 12-year warranty on heat exchanger, 5-year parts and 1 year labor.

This Rinnai RL94iN tankless gas water heater is in Rinnai’s high efficiency plus product line. It has a flow rate of 9.4 GPM, a maximum capacity up to four fixtures. It is recirculation capable and Wi-Fi capable. It comes standard with a MC-91-1US Digital Controller – which allows you to control the functions of the tankless and diagnose error conditions.

PROs:

• High-demand of flow rate 9.4 GPM. This Rinnai can provide tankless hot water for the whole house, up to five hot water outlet applications concurrently and continuously.
• An excellent temperature setting for residential use: 98°- 140°F. The standard setting for hot shower in residential home is 120°F.
• An excellent temperature setting for commercial usage: 98°- 185°F, operated with a Rinnai commercial controller (purchased separately).
• Energy saving. This non-condensing unit delivers up to 40% energy saving over a storage tank unit. And, this Rinnai uses a direct-spark electronic ignition, not the less energy efficient standing pilot.
• Space saving. At a dimension of 9.3” x 14” x 23”, this is a compact unit for a high-demand tankless.
• Excellent warranty. Rinnai provides 12-year warranty on heat exchanger, 5-year parts and 1 year labor for residential use.
• Concentric venting system. Rinnai was the pioneer manufacturer to use this unique direct venting system. The concentric venting system comprises of a single vent to process exhaust and fresh air. This interior-mount unit vents directly to the outside. It features an inner tube for exhaust, an outer tube for outdoors fresh air. The advantages of this unique system are direct vent and sealed combustion – key components for safety and performance.

CON:

• This Rinnai is an expensive high-end tankless gas water heater. The long term pay-back is totally worth the up-front purchase and installation costs.

Tips for installations:

• Size of gas line: either 1 3/4″ or 1/2″ gas line works, your gas technician can verify whether there is sufficient gas flow.
• You want to allocate budget to use a licensed contractor to install this unit properly, to fully qualify for the product warranty terms.

Tips for maintenance:

• Change the in-line screen filter periodically to maintain a debris-free filter.
• Flush your unit periodically to get rid of any scale and lime.

Summary

If you want to replace an existing hot water storage tank with a tankless water heater for your whole house, this Rinnai RL94iN with 9.4 GPM is worthy as a front runner for your consideration. Rinnai is a high-end and well-known brand. With its excellent warranty and its product durability, you can count on having continuous hot waters for decades. This model has an energy factor of 0.82 and it is WI-FI capable. A, an energy saving tankless brings more values to your property assessment and resale. Final verdict: quality product, excellent warranty, 24/7 customer service – Rinnai RL94iN is the winning choice for high-demand non-condensing option.

Medium Demand: Rinnai V75IN Low NOx Indoor gas Tankless Water Heater

Model: Rinnai V75IN Low NOx Indoor gas Tankless Water Heater
Dimensions: 17.5” D x 30” H x 13” W
Weight: 50 lb
Flow rate: 7.5 GPM.
Demand type: Medium-demand, most suitable for small to medium occupancy of 2-3 bedrooms household
Application: Single point-of-use or multiple applications; indoors and residential

Rinnai has been a top selling brand of tankless gas heaters in North America for years. Rinnai brand is reputable for having:

• Reliable and durable product. An average Rinnai lasts for 20 years.
• Excellent customer support. Rinnai has an in-house support 24/7 every day of the year, including holidays.
• Great product warranty. This Rinnai V75IN provides 10-year warranty on heat exchanger, 5-year parts and 1 year labor.

This Rinnai V75IN tankless gas water heater is in Rinnai’s value series. This medium demand tankless has many of the great features found in the more expensive models. It is also certified for installation in mobile homes. This Rinnai model has a flow rate of 7.5GPM, capable to run two showers and a dish washer the same time. It comes with a temperature controller – which allows you to control the temperature of the tankless and diagnose error conditions. The minimum and maximum temperature setting is 98°- 140°F. It has a temperature lock – so there is no accident in unintended temperature change.

PROs:

• Medium-demand of flow rate 7.5 GPM. This Rinnai can provide tankless hot water for two bathroom showers applications and a dishwasher concurrently and continuously.
• An excellent temperature setting for residential use: 98°- 140°F. It has a temperature lock to prevent accidental temperature change.
• Rinnai has certified this model for installation in mobile homes.
• Performance. 10,300 BTU/h 3.0 kWh (Minimum) / 180,000 BTU/h (Maximum)
• Environmental friendly – it is Low NOx emissions compliant, 20 ppm, doing our part for less pollution to the environment.
• Excellent safety features: leak detection shut off water. You have one less worry to limit potential water damage to your property.
• Energy saving. This non-condensing unit delivers up to 40% energy saving over a storage tank unit. And, this Rinnai uses a direct-spark electronic ignition, no need for the less energy efficient standing pilot light.
• Excellent warranty. Rinnai provides 10-year warranty on heat exchanger, 5-year parts and 1 year labor for residential use.

CON:

• It is hard to find disadvantages with this medium-demand unit at this price point. If you have a large four bathroom home, this medium-demand unit is not for you. Use a Rinnai vent in your installation.

Tips for installations:

• Check for terminal clearances. Avoid termination locations near a dryer vent.
• You want to allocate budget to use a licensed contractor to install this unit properly, to fully qualify for the product warranty terms..

Summary

This Rinnai V75IN Indoor Low NOx gas tankless is SCAQMD approved for ultra-low NOx emissions. It is a well-priced and reliable medium demand gas tankless water heater. Rinnai is a high-end and reputable manufacturer. We are happy that they added this more affordable model to their value series.

If you are looking for a medium demand, 7.5 GPM, gas tankless for a 2-3 bedroom homes, this Rinnai is a strong candidate for your consideration. You get performance (180,000 BTU/h), excellent safety features (leak detection and scale detection), environmental friendly Low NOx emissions compliant and excellent customer support and warranty from a top selling manufacturer Rinnai.

Best Seller: Takagi T-H3J-DV-N Indoor Natural Gas Condensing Tankless Water Heater

Model: Takagi T-H3J-DV-N Indoor Natural Gas Condensing Tankless Water Heater
Dimensions: 6.7” x 13.8” x 20.3”
Weight: 38 lbs.
Flow rate: 6.6 GPM.
Demand type: Medium-demand to low-demand, most suitable for low-to-medium occupancy of 2 bathrooms household.
Application: Single point-of-use or multiple applications.

This Takagi T-H3J-DV-N Indoor tankless is ideal for a medium-demand hot water usage household. Check out these notables: a 6.6 GPM flow rate, 140,000 BTU, and an energy factor of 0.81-0.83. This Takagi is also applicable for radiant heating system, for example supplying heat to the floor or panels in the walls of your house.

Takagi Corporation has been in the manufacturing business since 1952. They are highly reputable and being the “first” in many tankless innovations. Some of their notable successes including “direct vent convertible”, first to offer thermal efficiency of 95%, and first to offer an air-fuel ratio rod for safety.

PROs:

• Medium-demand of flow rate 6.6 GPM. This Takagi can provide tankless hot water for two bathroom household. For example, you can run two showers and a dishwasher concurrently and continuously.
• Excellent warranty. Takagi provides 15 years limited warranty on the heat exchanger, and a five years limited warranty on parts for residential use.
• It includes a remote controller, and a power cord in the packaging.
• Space saving. At a dimension of 6.7” x 13.8” x 20.3”, and weighs only 38 lbs., this Takagi unit has one of the smaller foot prints for a medium demand tankless heater.

CON:

• This Takagi has a good energy factor of 0.81-8.83 for a non-condensing tankless. It is less energy efficient than a condensing tankless.

Tips for installations:

• Vent pipe: use 4-Inch category III stainless steel venting.
• You want to hire a licensed contractor to install this unit to manufacturer spec and code, in accordance to the terms of product warranty.

Tips for maintenance:

• Have a licensed contractor checked your unit once a year, including venting system, pressure relief valve, and heat exchanger.

Summary

This Takagi T-H3J-DV-N is a best-seller for medium-demand gas tankless. It has received many excellent reviews from purchaser. It is cost-effective and environmentally friendly with an energy factor of 0.82 for a non-condensing model. Its safety design features are excellent – including freeze, overheat and surge protection.

Takagi T-H3J-DV-N is priced well for a medium-demand tankless, effective for light to medium residential and radiant heating applications. It is easy to maintain with trouble shooting diagnostic codes. And, Takagi provides one of the best warranty in the tankless business – this model carries 15 years limited warranty on the heat exchanger.

Key factors to consider before buying a tankless gas water heater:

To choose the best gas tankless unit for your home, here is a good check list to help you:

1. Centralized vs. point-of-use tankless water heater
   • A centralized tankless water heater is used when your best choice is to end up with a single water heater to meet all of the water heating needs of your house A centralized system is often cheapest and easiest to install, especially if replacing a centralized storage water heater.
   • Point of use tankless water heaters are primarily used in distributed systems intended to deliver hot water immediately at the point of use (for example, a shower or washing machine). This would typically imply your house or apartment would have several point of use heaters, although they can be used in combination with a centralized system to provide a local boost in temperature for a single point of use.
   • Read More about Centralized vs. point-of-use tankless water heater
2. Flow rate – How to size your hot water needs?
   • The single most important thing to understand in installing your new tankless system is what maximum flow rates you require to be able to take showers, washer close, etc.
   • You can use our guide to calculate your likely flow rates, although most people find it most beneficial to add an additional 50% or so in capacity to cover extreme loads or when the external water temperature is extremely cold.
   • Read More about how to size your hot water needs.
3. Types of tankless GAS water heaters: Condensing vs. Non-Condensing
   • Non-condensing: these gas tankless water heaters are typically 80 to 85% energy efficient and generally require high-temperature venting of exhaust gases with materials such as stainless steel.
   • Condensing: these gas tankless water heaters use a secondary cycle to recover even more heat from the exhaust gas to transfer to your water. Condensing gas tankless water heaters are typically 95% efficient or greater and generally require low temperature venting with plastic materials like PVC pipe.
   • As you might expect, noncondensing tankless heaters tend to have a lower initial purchase price but a somewhat higher ongoing operational cost. Installation costs can also differ because of venting requirements. These are all considerations in making your choice.
   • Read More about Condensing vs. Non-Condensing tankless gas water heaters
4. Benefits of Gas Tankless water heaters
   • Gas tankless water heaters produce hot water on demand and instantly.
   • Tankless water heaters are generally more energy efficient than their storage tank equivalents (condensing tankless water heaters are especially high in efficiency).
   • Because they are more energy efficient than storage tank water heaters, tankless water heaters are better for the environment.
   • Gas generally has lower operating cost than electricity (based on your local utility costs).
   • Gas tankless water heaters reach operating temperature more rapidly than electric tankless water heaters.
   • Gas tankless water heaters generally reduce or eliminate the “cold sandwich” problem where you may get a burst of cold water flowing into your shower first.
   • Read More about Benefits of Gas Tankless gas water heaters
5. On-demand water heater buying guide
   • Determine the size of tankless gas heater you need
   • Decide on condensing or non-condensing gas tankless
   • Indoor or outdoor use
   • Brands with excellent warranties
   • Buying and installation budget
   • Maintenance cost
   • Read More about Tankless water heater buying guide

Installation Tips for Gas Tankless Water Heaters:

• Always check with your local building code before you choose your installation location.
• For indoor gas tankless water heater, you want to make sure you have a direct vent piped to air outside.
• Inspect the venting system annually. Check all the venting sections are secure and airtight.
• Service Valve. Consider installing a service valve which makes it easy to purge any scale built up during your annual flush maintenance of your water heater.
• Pressure relief valve is required by building code in all states. It is used to relieve excess pressure that might build in your system due to overheating. Often a service value kit includes a relief valve.
• Burner. Inspect the burner in your annual maintenance. While the water heater is operating, inspect the main burner flames through the burner sight glass, the flames should be blue color when the main burner is firing.
• Termination vent. A termination vent is used where the vent passes through the wall of your house to the outside. In addition to being visually more attractive than a bare pipe passing through your wall, the termination will often provide a barrier to rodents or birds accessing that vent.

Want to consider an electric tankless model? Check out our top-rated list of electric on-demand water heaters.