Continuous Flow Hot Water Sizing: What Does a 26L Rating Mean?

If you are comparing continuous-flow heaters for your Illawarra home, the numbers can be confusing. A storage system might be listed as 250 litres, while a continuous-flow model is described as 26 litres. Those figures describe different things.

A storage rating refers to the tank. A continuous-flow rating describes how much water the heater can heat each minute under specified conditions. Understanding the difference helps you ask better questions before choosing a system.

A 26L unit does not contain a 26-litre tank

Continuous-flow heaters heat water as it passes through the appliance. They do not rely on a conventional storage tank.

For a specific example, Rinnai lists the Infinity Enviro 26 at 26 litres per minute for a 25°C temperature rise. Its published table lists 16 litres per minute at a 40°C rise. You can see those conditions in the manufacturer’s Infinity Enviro 26 specifications.

This is an example for that model, not a performance promise for every heater with “26” in its name.

Why temperature rise matters

Temperature rise is the difference between the incoming water temperature and the heated water leaving the appliance. Colder incoming water requires a greater rise to reach the same outlet temperature.

That is why a headline litre rating needs its test conditions alongside it. Ask your installer to assess the model against expected incoming water temperatures and the required delivery arrangement at your property.

For homes in Wollongong, Shellharbour, Kiama, Albion Park or Nowra, the useful question is how the selected system will perform at the actual home throughout the year.

Count outlets used together

The number of bathrooms is a starting point, but tell your installer which outlets are likely to run at the same time.

Consider two households with two bathrooms. One uses the showers separately. The other regularly runs both showers while someone uses hot water in the kitchen. Those routines should be discussed separately when selecting a heater.

If you know your showerhead flow rates, include them in the enquiry. The installer can assess the hot water portion of the combined demand; total mixed shower flow should not be treated as identical to heater outlet flow.

Check the installation as well as the rating

Ask whether the proposed heater is compatible with your gas type and whether the existing gas supply, pipework, water supply and installation position are suitable.

A model with a larger advertised output is not automatically a straightforward replacement. Confirm the exact product and installation requirements before ordering.

Browse Illawarra Hot Water’s continuous-flow gas systems to see available options, then compare the relevant manufacturer specifications.

Questions worth asking before you buy

• What output should I expect under the conditions assessed for my home?
• Can the system serve the outlets we regularly use together?
• Does the existing gas supply need any changes?
• What work is included in the installation price?

Contact Illawarra Hot Water with your current model details and household routine. Choosing from the full specifications gives you a stronger basis for the decision than relying on the litre number alone.