Comparison

Rinnai Central vs Optimal°

Price, ratings, monetisation and update history for both apps, side by side — with what reviewers say about each.

Head to head
About

Rinnai Central

This app connects Rinnai tankless water heater owners to their devices for temperature control and scheduling. Professional installers can use it to register appliances, perform service, access documentation, and order parts.

Highlights
  • Adjust water temperature
  • Schedule hot water
  • Activate recirculation
  • Register appliances
  • Perform remote service
  • Access documentation
  • Order replacement parts
Features
Read full description

Rinnai Central helps professionals support customers and gives homeowners convenient control of compatible Rinnai water heating systems from anywhere. For Rinnai PROs and installers, Rinnai Central makes it easier to register products, set up compatible customer devices, access service tools, and stay connected to Rinnai resources. For Rinnai tankless water heater owners, Rinnai Central provides convenient access to temperature control, recirculation settings, scheduling, system status, and maintenance alerts when supported by the connected product. PROFESSIONALS Use Rinnai Central to: ∙ Set parameters and perform service on compatible Rinnai tankless water heaters and boilers. ∙ Register eligible Rinnai products after installation. ∙ Set up and configure compatible customer Wi-Fi modules. ∙ Access product documentation, troubleshooting tools, training, rebates, news, and service resources. ∙ Find the right Rinnai product for your customer's needs. ∙ Access the Rinnai parts webstore. ∙ Manage your professional account and company relationship. ∙ Participate in eligible Rinnai PRO Tech programs when available. HOMEOWNERS Use Rinnai Central to: ∙ Adjust compatible water heating system temperature settings. ∙ Activate recirculation when supported by the product. ∙ Create daily schedules so hot water is ready when needed. ∙ Set vacation mode to help save energy when hot water is not needed. ∙ View real-time system status and maintenance alerts. ∙ Find experienced Rinnai PROs and installers near you. COMPATIBLE PRODUCTS Rinnai Central supports select Rinnai residential and commercial tankless water heaters and compatible accessories. Some features require a supported Rinnai Wi-Fi module or compatible connected product. Product availability, supported features, and access permissions may vary by model. - BLE setup is not available on all Rinnai products. Some products may require the RWM200 Wi-Fi Module accessory, sold separately. - For safety and product support reasons, some device setup and service permissions may be restricted to Rinnai professionals. Read our Data Use and Privacy Policy, Terms, and other important information in the legal section of our App Store description or at the web addresses below. TERMS OF SERVICE https://www.rinnai.us/terms-of-use PRIVACY POLICY https://www.rinnai.us/privacy-policy

About

Optimal°

This app provides remote control and monitoring for a specific brand of tankless water heaters. Users can adjust temperature, track performance metrics, and receive diagnostic information for efficient hot water management.

Highlights
  • Set water heater output temperature
  • Monitor unit activity state
  • Track flow rate and energy consumption
  • View inlet and outlet water temperatures
  • Access diagnostics and error codes
  • Enable Vacation Mode
Read full description

Control and Monitor your Optimal Opti Tankless Water Heater with the Optimal° connected app. Optimal° app allows you to control temperature, monitor performance and unit diagnostics, giving you full control of our hot water services. Optimal's patent pending ultrasonic flow sensors allow you to add your water heater to your smart home intelligence. Optimal° allows you to precisely customize how hot water is delivered to your faucets. Save money, be efficient and that's Optimal. Current App Version functionality. - Set water heater output temperature - Unit activity state (heating / not heating) - Gallons / min flow rate - Kilowatts per hour rate - Inlet Water Temperature - Outlet Water Temperature - Input Voltage - Available Flow Rate - Heater Capacity - Vacation Mode - Diagnostics / Error Code Reporting

Screenshots

Rinnai Central4 screens
Optimal°4 screens

Verdict

The call

The clearest difference is review sentiment: Optimal° at 60% against Rinnai Central's 9%. Optimal° also leads on rating (3.9 vs 1.6). Rinnai Central's advantage is update cadence (monthly vs every 5 months) and ratings volume (396 vs 9). On price, ads, in-app purchases and monetization model there is nothing between them.

Scored on Price · Rating · Positive reviews · Number of ratings · Update frequency · Ads · In-app purchases · Monetization · Best chart rank · Devices · Requires iOS

CostPrice · In-app purchases · Ads · Monetization

Both are free to download. Neither carries in-app purchases, so what you see is what you pay.

ReceptionRating · Positive reviews · Number of ratings

Optimal° holds the better App Store score, 3.9 against 1.6. That said, the two scores are not equally well evidenced: Rinnai Central has 396 ratings behind it against 9, so its average is the more settled of the two. Written reviews point the same way: 9% of Rinnai Central's written reviews are positive against 60% of Optimal°'s.

UpkeepUpdate frequency

Rinnai Central ships an update monthly, Optimal° every 5 months. The most recent releases landed on October 27, 2026 and October 24, 2026 respectively.

Scorecard4 real differences · 6 level
Rinnai Central versus Optimal°: the parameters behind the verdict, then further details
ParameterRinnai CentralOptimal°
PriceFreeFree
Rating1.6 (396 ratings)3.9 (9 ratings) — better
Positive reviews9.0% of reviews60.0% of reviews — better
Number of ratings396 — better9
Update frequencyMonthly — betterEvery 5 months
AdsNoNo
In-app purchasesNoNo
MonetizationFreeFree
DevicesiPhone, iPad, iPod — betteriPhone, iPod
Requires iOS15.4.115.1 — better
Further details — not scored
Size79 MB19 MB
Age rating4+17+
DeveloperRinnai America CorpIts Optimal LLC

Customer experience

Rinnai Central

All ratings341 ratings
Positive12.6%
Neutral3.5%
Negative83.9%
Written reviews223 reviews
Positive9.0%
Neutral4.5%
Negative86.5%

Optimal°

All ratings7 ratings
Positive100.0%
Neutral0.0%
Negative0.0%
Written reviews5 reviews
Positive60.0%
Neutral20.0%
Negative20.0%

Bugs and requests

Rinnai Central

Reported bugs

3 issues
  • Control failed is still happening in latest version
  • Login screen freezes
  • Incompatible with older devices

Requested features

3 requests
  • Add device through Bluetooth missing
  • Dark mode option
  • Advanced analytics dashboard

Optimal°

Not enough reviews yet to summarise bugs or requests.

In-app purchases

None

Rinnai Central

No in-app purchases

None

Optimal°

No in-app purchases

Questions

Is Rinnai Central free?
Rinnai Central is free to download, with no in-app purchases.
Is Optimal° free?
Optimal° is free to download, with no in-app purchases.
Which has better reviews, Rinnai Central or Optimal°?
Optimal° is rated higher. Rinnai Central averages 1.6 out of 5 from 396 ratings, while Optimal° averages 3.9 from 9 ratings.
Do Rinnai Central or Optimal° have ads?
Neither Rinnai Central nor Optimal° shows ads.
Which is updated more often, Rinnai Central or Optimal°?
Rinnai Central ships an update monthly, and Optimal° every 5 months. Most recently, Rinnai Central was updated on October 27, 2026 and Optimal° on October 24, 2026.

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