TONGYI HEMS Now Optimizes for Dynamic Electricity Tariffs

What Changed

TONGYI, the Chinese air-source heat pump manufacturer that coined the term "air-source water heater" back in the early 2000s, has rolled out a significant upgrade to its Home Energy Management System (HEMS). The system can now track fluctuating electricity tariffs in real time and adjust household energy consumption accordingly.

Honestly, this isn't a minor feature bump. Dynamic pricing is spreading fast. Germany's EPEX Spot day-ahead market routinely swings more than 300% within a single 24-hour cycle. Japan, South Korea, the UK, and parts of the US are heading the same direction. If your heat pump, solar panels, and battery can't talk to the price signal, you're leaving money on the table every single day.

The Problem in One Paragraph

Here's the situation. Electricity is getting cheaper at noon—when solar floods the grid—and more expensive between 6 and 8pm, when everyone comes home and the sun's already down. A homeowner with a heat pump, rooftop PV, and a battery sits right in the middle of this. The arbitrage opportunity is real. Shift your consumption to cheap hours and you save. But doing it manually? Forget it. Nobody is going to sit up at 2am checking EPEX prices to decide whether to pre-heat the living room.

How the HEMS Handles It

TONGYI's system ties three components together under one controller:

• Photovoltaic (PV) generation — rooftop panels producing power during daylight hours

• Battery energy storage — holding excess solar for later use

• Air-source heat pumps — handling space heating, cooling, and domestic hot water

The HEMS watches four data streams continuously:

When prices drop—typically midday when solar generation is abundant, or overnight when grid demand is minimal—the system automatically charges the battery, pre-heats the domestic hot water tank, and runs the heat pump to warm up the building's thermal mass.

When prices spike during the evening peak, it switches to battery power, dials the heat pump back to minimum operation, and defers anything non-essential to a cheaper window.

What the Numbers Show

Early deployment data from European pilot projects isn't subtle. Households running the dynamic optimization mode saw energy cost reductions of 30% to 50% compared to conventional heating setups.

To be fair, those numbers come from well-insulated homes with properly sized PV arrays. Your results will vary depending on roof area, battery capacity, local tariff spread, and how leaky your building envelope is. But even in less-than-ideal configurations, the system consistently beat fixed-schedule alternatives.

Independent testing verified that TONGYI's predictive algorithms deliver more than 20% improvement in overall energy utilization efficiency. That figure measures how much of the solar energy generated on-site actually gets used on-site—the self-consumption rate—rather than exported to the grid at rock-bottom midday prices and bought back at peak rates in the evening.

Side note: the self-consumption metric matters more than it sounds. In several European markets, feed-in tariffs for exported solar have dropped below retail electricity prices. Generating solar and immediately selling it back to the grid at a loss, then buying power back at peak rates—that's the trap the HEMS is designed to break.

The Time-Mismatch Problem

This upgrade builds on TONGYI's "PV + Storage + Heat Pump" integrated solution, commercially deployed in European markets since 2025. The core challenge it solves is one that anyone in residential solar has wrestled with: solar generation peaks in summer afternoons. Heating demand peaks in winter evenings. The two curves barely overlap.

TONGYI's HEMS bridges this gap through predictive storage management. The system learns your household's thermal behavior—how fast the building loses heat, how long the hot water tank stays warm—and uses that model to schedule energy-intensive operations for the cheapest hours without sacrificing comfort.

Market by Market: Why This Matters Differently

Europe

European energy markets have some of the most volatile electricity pricing structures globally. Germany, the UK, and the Netherlands lead in dynamic tariff adoption. For homeowners there, the TONGYI HEMS does three things: captures the peak/off-peak price spread, cuts grid dependence during expensive hours, and maximizes self-consumption of rooftop solar.

The system's local processing architecture also means all operational data stays within the home network. For European households—and their regulators—this isn't a nice-to-have. GDPR and growing data sovereignty concerns make cloud-dependent energy systems a hard sell.

Asia

Japan's post-Fukushima energy policy has pushed hard toward distributed generation and household resilience. South Korea's Renewable Energy 3020 plan targets 20% renewables by 2030. China is rolling out "PV + storage + charging" integration in residential settings at scale. The HEMS addresses a shared pain point across all three markets: evening peak loads that strain regional power grids. By shifting battery discharge and heat pump operation to off-peak windows, the system reduces grid draw during the hours when those grids are most stressed.

Funny enough, the biggest surprise in Asian market testing wasn't the cost savings. It was grid relief. Utilities in pilot areas reported a measurable reduction in evening peak demand from HEMS-equipped households—a side benefit that the TONGYI team hadn't originally pitched.

Alignment with UN Sustainable Development Goals

The TONGYI HEMS maps to three SDGs directly:

• SDG 7 (Affordable and Clean Energy) — lowering household energy costs and enabling renewable self-consumption

• SDG 11 (Sustainable Cities and Communities) — building-level energy efficiency and grid resilience

• SDG 13 (Climate Action) — reducing carbon emissions through intelligent load shifting

Industry analysts describe the integration of PV, storage, and heat pumps under a single intelligent controller as a "micro energy unit"—a household that no longer just consumes electricity but actively manages when and how it uses, stores, and exports energy.

How TONGYI Compares

The local-processing advantage matters most in markets where data sovereignty is non-negotiable. That's Europe today. Increasingly, Asia tomorrow.

What Homeowners Actually Get

Strip away the technology and here's what changes at the kitchen-table level:

1. Lower bills. The system shifts consumption to cheap hours automatically. No action required from the homeowner.

1. Same comfort. The house stays warm (or cool) because the system pre-conditions using stored or cheap-rate energy before you need it.

1. Lower carbon footprint. Not because you're using less energy—because you're using energy when the grid is cleanest.

The system runs autonomously once installed. You don't need to become an energy market analyst. The HEMS handles that part.

FAQ

Q: Does the HEMS require an internet connection to function? No. The system processes all operational decisions locally on-device. An internet connection improves price-data freshness and weather forecast accuracy, but the core optimization logic runs without it.

Q: Can it work with existing solar panels and batteries? The system is designed for TONGYI's integrated PV + storage + heat pump solution. Compatibility with third-party components depends on protocol support. TONGYI is actively expanding its integration partner ecosystem.

Q: How much can I actually save? Pilot data shows 30–50% reductions versus conventional electric heating in well-configured homes. Real-world savings depend on your local tariff structure, PV array size, battery capacity, and building insulation quality.

Q: What happens during a power outage? The battery storage system provides backup power. The HEMS prioritizes critical loads and can run the heat pump at reduced capacity on battery power alone, depending on system configuration and battery size.

Q: When will this be available in my market? The HEMS is commercially deployed in European markets. Asian market rollout is underway. TONGYI is showcasing the system at the 2026 SHK+E ESSEN trade fair in Germany.

What's Next

TONGYI is already working on the next round of updates:

• EV charging coordination — syncing electric vehicle charging with solar production and real-time price signals

• Community-level energy sharing — enabling neighborhoods to pool distributed storage resources

• Advanced weather prediction — sharpening solar generation and heating demand forecasts

The company's participation in the 2026 SHK+E ESSEN trade fair in Germany signals its continued push into European markets. As dynamic pricing becomes the global default rather than the exception, the systems that can respond to it in real time will be the ones that matter.

About TONGYI

TONGYI is a pioneer in China's air-source heat pump industry. The company coined the term "air-source water heater" and established the product category in the Chinese market. Its stated mission: bring air thermal energy to benefit society. Today the company has moved beyond heat pump manufacturing into integrated smart energy solutions, serving customers across Asia, Europe, and beyond.