Cloud Dependency

Many device APIs only work via cloud services, causing latency issues and failing during grid outages when local coordination is needed most.

The Problem

HEI devices desire and require connection to the Internet and cloud services. Typically this is for connection to the manufacturer's cloud, firmware updates, and to enable smartphone apps for homeowner monitoring and control.

However, some manufacturers provide only cloud-based APIs for device integration. This architectural choice has serious consequences for home energy management.

Latency Issues

Even in the best case, cloud-based APIs suffer from latency issues. A simple request to read a device's current state must travel:

sequenceDiagram
    participant HEMS as Your HEMS
    participant Cloud as Manufacturer Cloud
    participant Device as Device

    HEMS->>Cloud: API Request (via Internet)
    Note over Cloud: Processing
    Cloud->>Device: Forward to device (via Internet)
    Device-->>Cloud: Device response
    Cloud-->>HEMS: API Response

Round-trip time: 100-500ms+ (vs. <10ms for local communication)

For real-time energy management decisions - like responding to rapid changes in solar production or managing power during a grid event - this latency is unacceptable.

Failure During Grid Outages

The most critical time for HEI device coordination is during a grid outage. Your battery, solar, EV charger, and transfer switch need to coordinate to keep your home powered safely. Yet this is precisely when cloud APIs are most likely to fail.

Grid Outage Scenario

When the grid goes down:

Your internet connection may also fail (cable modem needs power, ISP infrastructure affected)
Even if your home network stays up, the manufacturer's cloud may be unreachable
Cloud services themselves may be affected by widespread outages
High demand on cloud services during regional events causes slowdowns

Result: Your devices can't coordinate at exactly the moment when coordination is most critical. Your battery doesn't know to start discharging. Your solar doesn't know it needs to curtail. Your EV charger doesn't know it can provide backup power.

The Irony

Cloud-dependent devices are least reliable exactly when reliability matters most. Grid outages are when you need your home energy system to work perfectly - and when cloud connectivity is least certain.

Privacy and Security Concerns

Cloud-only APIs also raise significant privacy and security concerns:

Data exposure: Detailed energy usage patterns reveal when you're home, your daily routines, and what appliances you use
Third-party access: Your data passes through manufacturer servers, potentially accessible to employees or breaches
Service discontinuation: If the manufacturer shuts down cloud services, your device integration stops working
Account requirements: You must create accounts and agree to terms of service just to control devices you own

Impact on Homeowners

Energy management fails during outages when it's needed most
Latency prevents real-time optimization
Privacy-sensitive data leaves your home
Dependency on manufacturer's continued cloud operation
Internet outage = loss of device control

Why Manufacturers Choose Cloud

Easier development: Cloud APIs are simpler to secure and update than local APIs
Data collection: Usage data has business value for product improvement and monetization
Recurring revenue: Cloud services can enable subscription features
Support simplicity: All traffic flows through controlled infrastructure

How eBus Solves This

eBus mandates that all API access MUST be local, not via a cloud. Devices communicate directly on your home network using standard protocols (MQTT over IP).

This means your home energy system continues to work during internet outages, responds in milliseconds instead of hundreds of milliseconds, and keeps your data on your network.

Devices can still connect to manufacturer clouds for firmware updates and smartphone apps - but local integration doesn't depend on it.

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