My smart meter is on the home network. Home Assistant is on the home network. So why can’t Home Assistant simply ask the meter how much power the house is using?
That question came up while I was trying to understand what a roughly 3.6 kW hot-water element would do to household consumption. At 240 V, that element is around 15 A. A live whole-home meter should make the change easy to spot. Instead, the Tuya meter and two other Tuya devices had all gone unavailable in Home Assistant.
Being on Wi-Fi does not mean Home Assistant can talk to it locally
“It’s on the network” sounds like the hard part is solved. The device has joined the wireless network, received an address and can probably reach the internet. But that does not tell Home Assistant which local protocol to use, whether the device exposes one, or whether the integration is using it.
In this setup, Home Assistant uses its Tuya integration to connect through Tuya’s cloud service. The meter can be connected to Wi-Fi and still depend on a working Tuya account session before Home Assistant receives its readings. The built-in integration is cloud based; it does not automatically discover and control every Tuya device directly over the LAN. Home Assistant’s Tuya integration documentation describes the account and QR-code setup.
What failed in this case
After an internet outage, I checked the Home Assistant entities and the integration state. The Tuya integration was in an error state, and the meter’s phase-power reading was unavailable. Two Tuya smart plugs on the same account were unavailable as well. Home Assistant could reach Tuya’s cloud gateway, but the integration’s saved authentication was being rejected.
That distinction matters. The outage was a reasonable first suspect, but the evidence pointed to an authentication problem in the shared cloud integration, not proof that the meter had fallen off Wi-Fi. When several devices behind one integration fail together, the shared account session is an important place to look.
The recovery path is to reauthenticate the existing Tuya integration by scanning a QR code with the Tuya Smart or Smart Life app. Home Assistant’s troubleshooting notes also warn that changed Tuya IoT terms can lead to repeated reauthentication until the terms are accepted. That can restore service, but it does not answer the bigger question: why does a local power reading need a cloud login at all?
The cloud becomes a single point of failure
A cloud connection can make onboarding easy. It can also put the vendor’s account service between a device and the home automation system. A lost internet connection, expired session, changed terms, regional service problem or vendor outage can interrupt a feature that seems local from the user’s point of view.
In my case, losing the meter means losing the information needed to compare household load before and during hot-water heating. The heater’s nominal 3.6 kW draw should be visible as a substantial change, but I cannot use an unavailable sensor to prove that. A smart-home dashboard can look complete while its underlying data path is broken.
What I want from a smart device
I do not expect every cheap Wi-Fi device to support every feature locally. I do expect the connection method to be clear before I buy it. For anything important, I want a documented local API or a well-supported local protocol, useful diagnostics, and basic operation that continues when the internet is down. Cloud access can be an extra; it should not be the only door.
- Check whether Home Assistant communicates with the device locally or through the vendor’s cloud.
- Look for a documented local API and confirm the exact model and firmware are supported.
- Check what still works when the internet or vendor account is unavailable.
- Keep essential control on a local device, and treat cloud-dependent readings as optional until their failure modes are understood.
- When several devices disappear together, check the shared integration and authentication before changing Wi-Fi settings.
A device should not need permission from the internet to report local power
I can restore the Tuya login and get the meter back into Home Assistant. That is the immediate fix. The longer-term lesson is to choose devices whose local behaviour is documented and testable. If a device is already on the home network, it is fair to ask why its basic data cannot stay on that network too.
Until the meter is reporting again, I cannot confirm the household consumption change from the hot-water element. When it does return, the next useful check is simple: compare a stable baseline with the reading while the element is actually heating. That will tell me whether the measurement is plausible, and whether this smart meter is earning its place in the system.
Related: How to keep hot water running when Home Assistant goes down.