10 Condensing Water Heater Vs Non Condensing of 2026 for Simpler Venting

1

Rheem RTG-84XLN-3 High Efficiency Non-Condensing Outdoor Tankless Natural Gas Water

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  9.7
• Brand
  Rheem

Key specs2

Venting design

Exterior wall mounting discharges exhaust directly into open air, eliminating the cost and layout disruption of running vent pipes through ceilings or walls.

Simultaneous shower capacity

8.4 GPM (3 to 4 showers at 35°F rise)

Pros & cons42

Pros

• Outdoor wall-mount design eliminates the need for indoor exhaust venting and wall penetrations
• Delivers 8.4 GPM at a 35 degree rise with 180,000 BTU per hour to run 3 to 4 showers at once
• Compact 39.25 lb metal cabinet saves indoor utility space and mounts directly to exterior walls
• Digital LED control panel enables precise temperature adjustments in 1 degree increments

Cons

• Lacks built-in WiFi connectivity for mobile temperature monitoring
• Outdoor installation requires a suitable exterior wall near an existing natural gas supply line

2

Rheem RTG-84DVLP-3 High Efficiency Non-Condensing Indoor Tankless Liquid Propane Water

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  9.6
• Brand
  Rheem

Key specs2

Fuel line requirement

Dedicated Liquid Propane (LP) only

Indoor venting setup

Requires a compatible direct-vent pipe system through an outside wall or ceiling to pull fresh air and vent exhaust safely.

Pros & cons42

Pros

• Dedicated liquid propane burner produces 180,000 BTU per hour for homes off the natural gas grid
• Supports 3 to 4 simultaneous showers with an 8.4 GPM flow rate at a 35 degree rise
• Direct-vent indoor setup brings in fresh combustion air without acidic condensate line routing
• Backed by a 15-year heat exchanger warranty and a 5-year parts warranty

Cons

• Requires dedicated direct-vent piping to route exhaust outside through an exterior wall or roof
• Liquid propane fuel requires an on-site storage tank and cannot run on standard natural gas lines

3

Rheem RTG-70DVLP-3 High Efficiency Non-Condensing Indoor Tankless Liquid Propane Water

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  9.5
• Brand
  Rheem

Key specs2

Fuel line requirement

Liquid Propane (LP) supply line

Flow rate rating

7.0 GPM at 35°F rise (160,000 BTU/hr)

Pros & cons42

Pros

• Sized for 2 to 3 simultaneous showers with 160,000 BTU per hour on liquid propane fuel
• Direct-vent indoor installation protects the unit from cold outdoor weather exposure
• Space-saving wall-mount profile frees up floor space previously occupied by tank water heaters
• Digital LED display allows simple water temperature adjustments by single-degree increments

Cons

• Flow rate of 7.0 GPM can restrict simultaneous shower use in large four-bathroom homes
• Requires running direct-vent pipes outdoors and connecting to a dedicated propane supply

4

Rheem RTG-70XLN-3 High Efficiency Non-Condensing Outdoor Tankless Natural Gas Water

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  9.3
• Brand
  Rheem

Key specs2

Venting design

Direct exterior exhaust venting removes the need to cut interior vent runs or add condensate drainage pipes.

Cabinet dimensions

9.4 x 13.5 x 20.75 inches (39.25 lb)

Pros & cons42

Pros

• Outdoor configuration completely bypasses the need for indoor venting and condensate drains
• Sized at 7.0 GPM and 160,000 BTU per hour to handle 2 to 3 showers running together
• Lightweight 39.25 lb metal cabinet hangs cleanly on exterior walls with included hardware
• Integrated freeze and flame failure protection safeguards outdoor components during cold snaps

Cons

• Unprotected exterior placement leaves the metal casing exposed to severe outdoor weather
• Operates exclusively on natural gas and cannot connect to liquid propane tanks

5

Rheem RTG-95DVELN-3 High Efficiency Non-Condensing Indoor Tankless Natural Gas Water

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  9.3
• Brand
  Rheem

Key specs2

Smart connectivity

Built-in WiFi enabled

Peak heating output

199,900 BTU/hr (9.5 GPM at 35°F rise)

Pros & cons42

Pros

• Delivers high output of 199,900 BTU per hour and 9.5 GPM for demanding multi-bathroom homes
• Integrated WiFi capability lets homeowners track water heating status and adjust settings remotely
• Direct-vent system pulls combustion air from outside without requiring acidic drain lines
• 15-year heat exchanger warranty provides long-term coverage for indoor residential use

Cons

• High 199,900 BTU per hour gas demand may require verifying existing gas supply line sizing
• Direct-vent indoor routing requires proper clearance and wall penetration hardware

6

Rheem RTG-70DVLN-3 High Efficiency Non-Condensing Indoor Tankless Natural Gas Water

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  8.9
• Brand
  Rheem

Key specs2

Water damage prevention

Built-in LeakGuard leak detection and prevention system actively detects internal moisture to safeguard indoor living areas.

Flow rate rating

7.0 GPM (2 to 3 simultaneous showers)

Pros & cons42

Pros

• Integrated LeakGuard detection monitors internally to spot water leaks before damage spreads
• Delivers 7.0 GPM at a 35 degree rise to supply hot water for 2 to 3 simultaneous showers
• Non-condensing direct-vent design avoids routing acidic condensate lines across basement floors
• Digital LED display offers precise single-degree temperature settings for steady water output

Cons

• Flow capacity is limited to 7.0 GPM compared to 8.4 and 9.5 GPM models in larger households
• Does not include wireless app connectivity for remote water heater management

7

Rheem RTG-70XLP-3 High Efficiency Non-Condensing Outdoor Tankless Liquid Propane Water

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  8.7
• Brand
  Rheem

Key specs2

Propane outdoor setup

Engineered specifically for exterior installation using a liquid propane fuel supply, avoiding indoor ductwork and venting penetrations.

Wall bracket footprint

39.25 lb exterior wall mount

Pros & cons42

Pros

• Outdoor propane setup requires zero indoor venting pipes, reducing retrofit installation complexity
• Supplies 7.0 GPM at 35 degree rise with 160,000 BTU per hour for 2 to 3 simultaneous fixtures
• Built-in freeze protection and durable metal cabinet protect internal components outside
• Wall-mount format weighs 39.25 lb to simplify exterior mounting on residential framing

Cons

• Must connect to a dedicated liquid propane tank rather than standard residential utility gas
• Lacks WiFi functionality for checking temperature or operation from inside the home

8

Rheem RTG-84DVLN-3 High Efficiency Non-Condensing Indoor Tankless Natural Gas Water

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  8.7
• Brand
  Rheem

Key specs2

Indoor venting setup

Connects to an indoor direct-vent system that draws outside air and exhausts combustion gases without producing acidic condensate.

Simultaneous shower capacity

8.4 GPM (3 to 4 simultaneous showers)

Pros & cons42

Pros

• Robust 180,000 BTU per hour rating supports 3 to 4 simultaneous showers via natural gas
• Direct-vent indoor installation protects the heater from outdoor temperature swings
• Digital LED control panel provides precise water temperature adjustments down to 1 degree
• Wall-mounted indoor cabinet replaces bulky tank heaters to recover floor space

Cons

• Does not offer built-in wireless smart controls found on WiFi-equipped models
• Requires dedicated direct-vent exhaust venting routed to an exterior wall or roof

9

Rheem High Efficiency Non-Condensing Outdoor Tankless Liquid Propane Water Heater,

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  8.6
• Brand
  Rheem

Key specs2

Propane outdoor setup

Outdoor liquid propane configuration eliminates indoor venting runs while supplying high flow for multiple bathrooms.

Exterior freeze protection

Built-in freeze and flame protection

Pros & cons42

Pros

• Generates 180,000 BTU per hour on propane to power 3 to 4 simultaneous showers outdoors
• Exterior mounting avoids cutting holes for indoor venting or managing condensate drainage
• Built-in freeze protection prevents outdoor pipe and burner damage in chilly conditions
• Compact 9.4-inch depth mounts unobtrusively on exterior home siding or masonry

Cons

• Demands a properly sized liquid propane storage tank and dedicated gas supply line
• No built-in WiFi connectivity for remote temperature adjustments or troubleshooting

10

Rheem RTG-95DVLN-3 High Efficiency Non-Condensing Indoor Tankless Natural Gas Water

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  7.3
• Brand
  Rheem

Key specs2

Peak heating output

199,900 BTU/hr (9.5 GPM at 35°F rise)

Wall space profile

10.27 x 13.5 x 24.2 inches (46.5 lb)

Pros & cons42

Pros

• Generates 199,900 BTU per hour to deliver 9.5 GPM for high-demand, 3 to 4 shower homes
• Direct-vent configuration exhausts safely outdoors without requiring acidic condensate drain lines
• Wall-mount format frees up utility room floor space while keeping the heater protected indoors
• Digital LED display enables exact 1 degree temperature settings for steady water output

Cons

• Standard configuration does not include WiFi connectivity for app-based controls
• The 199,900 BTU per hour natural gas demand requires verifying home gas meter and pipe sizing

Last update on 2026-10-17 / Affiliate links / Images, Product Titles, and Product Highlights from Amazon Product Advertising API

Do non-condensing tankless water heaters require a dedicated condensate drain line?

No, non-condensing gas tankless water heaters do not require a condensate drain line or an acid neutralizer. Condensing units extract exhaust heat until water vapor condenses into an acidic liquid that requires dedicated drainage pipes. Non-condensing units vent hot exhaust gases directly out of the system before condensation forms. This design avoids the need for condensate pumps, floor drains, or extra plumbing penetrations through floors and finished walls.

Can an outdoor non-condensing water heater eliminate indoor venting modifications?

Yes, choosing an outdoor non-condensing model eliminates indoor venting pipes and ceiling penetrations entirely. Outdoor units mount directly on an exterior wall and discharge combustion exhaust directly into open air from the cabinet. This setup bypasses the structural remodeling and wall alterations often required when routing metal vent pipes inside a home. If outdoor mounting is not practical for your layout, indoor units require dedicated direct venting to maintain safe indoor venting through an exterior wall or roof.

How do flow rates at a 35 degree temperature rise affect household hot water delivery?

Household hot water volume depends directly on your incoming groundwater temperature and fixture demand. Non-condensing units provide 7.0 GPM at 160,000 BTU, 8.4 GPM at 180,000 BTU, or 9.5 GPM at 199,900 BTU when operating at a 35 degree Fahrenheit temperature rise. When incoming cold water requires a steeper temperature rise during winter, the usable flow rate drops accordingly. Check the flow ratings of your showerheads and verify your regional incoming water temperature to confirm that your selected capacity prevents pressure drops during simultaneous use.

What should you verify when choosing between natural gas and liquid propane models?

You must confirm your fuel supply type before purchasing because non-condensing tankless heaters are built with dedicated factory gas configurations for either natural gas or liquid propane. Natural gas units connect to utility supply lines, while liquid propane models require dedicated propane storage tanks. These configurations cannot be swapped without specific manufacturer conversion procedures. Always check your fuel line diameter, supply pressure, and regulator setup against the appliance rating requirements to ensure proper combustion.

How does non-condensing tankless efficiency compare to a 50-gallon storage tank?

Non-condensing gas tankless water heaters deliver a 0.82 Uniform Energy Factor (UEF) and save up to 34% on energy costs compared to standard 50-gallon electric tank heaters. Traditional storage tanks consume energy continuously to keep standing water hot, resulting in ongoing standby losses. Non-condensing units heat water on demand only when a fixture opens, providing continuous hot water without maintaining a heated storage volume. If you prefer to avoid gas piping modifications altogether, you can also evaluate an electric tankless water heater that matches your home panel capacity.

What are the physical dimensions and weight differences between indoor and outdoor models?

Outdoor non-condensing units measure 9.4 x 13.5 x 20.75 inches and weigh 39.25 pounds. Indoor non-condensing models measure 10.27 x 13.5 x 24.2 inches and weigh 46.5 pounds, with WiFi-enabled configurations weighing 46.54 pounds. Indoor units are slightly taller and deeper to house direct-vent exhaust fittings and indoor combustion components. Measure your intended wall space, check structural stud spacing, and confirm side clearances before mounting either style.