BUYING GUIDE
How Many GPM Does Your Home Need?
Your target GPM is the combined flow of hot-water fixtures that may run together—not every fixture in the home. Temperature rise must be checked at the same time.
KEY POINTS
What to understand first
Use simultaneous flow
Build the total around realistic overlap.
Use actual fixture data
Labels or measured flow are more useful than generic averages.
Check temperature rise
A colder inlet means the heater must add more heat.
Read the full chart
Match the total flow and rise to the exact model performance data.
PLAIN-LANGUAGE GUIDE
Turn household routines into a flow estimate
Think about the busiest repeatable period: perhaps two showers, or one shower plus a kitchen faucet. Add only those flows. A fixture that never overlaps does not belong in the peak total.
Then test that flow against a cold-season temperature rise. A model’s maximum GPM is meaningful only under its stated conditions.
PRACTICAL CHECKLIST
Build a practical GPM estimate
Use this list to organize the information needed for a model-specific decision.
Map the busy period
Write down which hot-water fixtures overlap.
Find each flow rate
Use the fixture specification or a measured value.
Add the overlapping flow
Keep non-overlapping fixtures out of the total.
Calculate temperature rise
Use a realistic local inlet temperature.
Check the exact model
Review output at both values.
Leave room for real use
Discuss reasonable variation with the installer without guessing an arbitrary buffer.
WORKED METHOD
Example method
If two fixtures may overlap, add their measured hot-water flows. Then calculate the rise from the cold-season inlet temperature to the intended outlet setting.
COMPARE VERIFIED OUTPUT
Use verified product data as the final check
These current NOVIEEX gas models show why both output and installation location belong in the comparison.
INDOOR 4.75 GPM EXAMPLE
NOVIEEX Tankless Gas Water Heater – Propane 4.75GPM
- Indoor
- Propane
- Up to 4.75 GPM
OUTDOOR 5.3 GPM EXAMPLE
NOVIEEX Tankless Gas Water Heater – Propane 5.3GPM
- Outdoor
- Propane
- Up to 5.3 GPM
COMMON QUESTIONS
Frequently asked questions
Is GPM the same as water pressure?
No. GPM is flow rate; pressure is the force moving water through the system.
Should I use summer inlet temperature?
Use a realistic cold-season value for conservative sizing.
Can I choose from GPM alone?
No. Fuel or electrical capacity, installation location and model requirements also matter.
NEXT STEP
Compare Water Heater Output
Continue with the current NOVIEEX product information and model-specific requirements.