Navisizer 4+


Designed for iPad

    • 2.3 • 25 Ratings
    • Free



NaviSizer is designed to assist with sizing of domestic hot water heating systems with Navien NPE Series tankless water heaters.

For residential applications, NaviSizer offers system sizing, calculation of operating cost and savings, and provides a comprehensive output to be used as a job spec.

For commercial applications, NaviSizer uses ASHREA Hunter Curve calculations to size a broad range of applications. Both tankless and tankless with storage solutions are offered along with a comprehensive system spec that can be saved, printed, or emailed.

What’s New

Version 2

We updated all the model lines and improved functionality.

Ratings and Reviews

2.3 out of 5
25 Ratings

25 Ratings

choir_boy ,


App is very buggy and does not have a well designed UI. When I came to the part of the app to enter number of people and number of bathrooms I would click on the field and the keyboard would open briefly and then close and I was not able to enter any of the information.

Jalapeño hvdjs ,

Ask a lot and explain nothing

I am a homeowner. I am interested in this product and was hoping this app could connect me to either a licensed retailer or someone qualified to install it. I found neither. When they ask you for different information about your use of water, flow rate, gas bills, etc, they use too many acronyms and don’t explain what they are or how a layman can calculate any of it. They don’t explain the different products either or what the differences are. They need to go back and rethink this app for people who aren’t plumbers or engineers.

rottenSalsa ,

Great APP, accurate results

This APP uses real conditions and the Hunter curve to accurately size tankless units for both my residential and commercial projects. I’m quite happy with the results.

App Privacy

The developer, Navien, indicated that the app’s privacy practices may include handling of data as described below. For more information, see the developer’s privacy policy.

Data Not Linked to You

The following data may be collected but it is not linked to your identity:

  • Contact Info

Privacy practices may vary, for example, based on the features you use or your age. Learn More

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