From solar to EVs: How HEMS delivers up to over €1000/year in household energy savings

Rising costs, shifting tariffs, tougher rules – sounds like chaos. But with the right technology, it’s a goldmine. In this article, we break down exactly where those savings come from: maximization of solar power, optimized electric vehicle (EV) charging, dynamic tariffs, §14a compliance and more.

HEMS is what turns all that complexity into real, hands-off value. It syncs solar, heat pumps, EVs and batteries, so your customers save more without lifting a finger – and you deliver more than just hardware.

Welcome to energy, evolved.

Save up to €340/year by syncing with sunshine

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Let’s be honest: just installing solar panels isn’t enough anymore. The real question is what are you doing with that power? With a home energy management system (HEMS), homeowners don’t just produce solar  –  they use it more intelligently to slash their bills and keep their energy local.

Instead of blindly filling the home battery the moment the sun rises (like most basic setups do), a smart HEMS thinks ahead. It might feed energy into the grid when demand is high in the morning, then charge the battery during peak midday production  –  when solar penetration is high and grid strain is real. This kind of timing matters. It avoids curtailment, supports grid stability and yes, keeps your energy bill lower.

And while it’s silently working in the background, it’s also making sure your EV, battery or heat pump runs when solar’s peaking  –  not when the grid’s most expensive.

Take heat pumps, for example. A HEMS can tell them to preheat during sunny midday hours, storing cheap energy as heat. That simple shift? It can save households up to €340 a year  –  just by heating water when the sun’s doing its best work.

The bonus? It’s all automated. No micromanaging, no comfort compromises. Warm homes, hot showers, smaller bills.

Now let’s not forget the installers and energy partners. For them, this isn’t just about energy nerd points. It’s a real value proposition: customers stay compliant with the latest regulations, reduce their grid reliance and squeeze every drop of value from their photovoltaic (PV) investment  –  all without lifting a finger.

Smart, future-proof and easy to sell. What’s not to love?

Up to €430/year through smart compliance with §14a EnWG

With §14a EnWG, German homeowners can knock €100–150 off their annual energy bills – just by allowing energy-consuming devices to be dimmed in emergency situations. Got a heat pump or EV charger? Even better. High-consumption households that make their systems steerable can unlock reduced grid fees or qualify for special tariffs. For larger setups, the savings from energy can reach up to €430 per year. That’s certainly not nothing.

And while basic controllability is enough to meet the legal requirements, a smart system like a HEMS takes it further – automatically shifting loads while minimizing disruption and maximizing transparency and comfort.

But here’s the catch: most homeowners aren’t exactly thrilled about handing over control to grid operators. Fair enough. It sounds like a recipe for cold showers, half-charged cars and higher installation costs.

Enter HEMS – your buffer between grid rules and real-life comfort.

HEMS makes §14a compliance seamless. It connects assets to the DSO’s signals, reacts in real time and keeps everything running smoothly behind the scenes. Need to throttle down the heat pump? Fine – but HEMS makes sure the home stays toasty by leaning on solar, storage or clever scheduling. EV charging gets shifted, not shut off. Lights stay on, temp stays comfy and no one’s the wiser.

Better yet, HEMS provides the control and measurement platform that §14a demands – ensuring compliance, logging events and protecting your customer’s eligibility for those sweet, discounted grid tariffs.

So if you’re an installer, here’s the pitch:

“With a HEMS, your EV charger or heat pump is §14a-ready.”
That means homeowners qualify for the low-tariff perks without having to micromanage their energy use like it’s a second job.

Let’s go a bit deeper:
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– No smart meter? Module 1 gets you €142 flat per year for simply being controllable.
– Larger setup? Module 2 slashes 60% off grid fees – but you’ll need a separate meter.
– Got a smart meter? Module 3 is where it gets spicy: time-variable grid fees, perfectly managed by (you guessed it) HEMS.

But §14a is just the beginning. Sure, it’s about occasional power capping today – but smart load shifting is where the real potential lies. With a HEMS, you're not only ready for §14a but also prepped for what’s next: dynamic tariff optimization, intraday scheduling and upcoming rules like §9 EEG and §19 StromNEV. Grid operators aren’t out to take control – they’re pushing for a smarter system. And with HEMS, you’re always one step ahead, cutting costs and emissions without lifting a finger.

Bottom line? HEMS turns the need for grid compliance into an advantage. Lower bills, smarter control and a system that quietly works in your customer’s favor. It’s not just regulation  –  it’s opportunity. Wrapped up in one sleek, sellable solution.

€300–€550/year saved with dynamic tariffs

Dynamic tariffs are electricity prices that change based on time of day or market conditions. Think day-ahead hourly prices or simple peak vs off-peak rates. The idea? Use energy when it’s cheap, avoid it when it’s not. Simple – in theory.

But here’s the catch: without automation, most people miss the low-price windows. They charge the EV at dinner (expensive), use the heat pump when prices spike and basically pay more than they need to.

And then there's the big worry – what if you use energy when it’s at its most expensive? That’s exactly why a HEMS is key. It doesn’t just chase low prices – it uses intelligent forecasting and holistic optimization to actively avoid high ones. Like traditional flat-rate tariffs that cushioned wholesale market volatility, a HEMS automatically shifts loads to dodge price spikes. You stay flexible without getting burned.

HEMS makes it happen – 25% off your power bill (up to €250/year)

A HEMS knows when power is cheap and shifts your energy-hungry devices – heat pumps and EV chargers – to run at the right time. No micromanaging, no guesswork. Just automated energy savings.

And behind that magic? XENON’s dynamic tariff optimization. Every day, it grabs day-ahead electricity price signals, crunches the numbers in the cloud and builds a forecast-based plan tailored to your home’s energy habits – like when the EV needs charging or the heat pump should kick in. But it doesn’t stop there. The plan also factors in local constraints: PV production, fuse limits, §14a compliance – the whole picture. It’s then sent straight to the gridBox, which makes sure your devices steer clear of high-price hours and run when electricity’s cheap and clean.

Take this example: if power costs 20 €ct/kWh at 6 p.m. but drops to 10 €ct/kWh at 1 a.m., your EV charge doesn’t happen during the dinner rush – it waits until the low-cost window. Multiply that logic across your whole setup, and you’ve just turned time into money.

The result? Our simulations show that households using this setup slash their electricity costs by over 25%  –  that’s around €150–€200/year saved, just by letting HEMS do its thing.

And the best part? It’s all automated. No spreadsheets, no phone reminders – just smart tech making smart moves, day in and day out.

But wait  –  there’s more.

Time-variable grid fees = another up to €180/year

Grid fee structures are finally catching up. Starting April 1, 2025, time-variable grid fees kick in under §14a EnWG. In plain terms: it’s no longer just about how much electricity you use, but when you use it. Some utilities are already testing the waters with static peak/off-peak rates and many more are gearing up to follow.

Until now, even “dynamic” tariffs were more like half flexible. Sure, you could chase low wholesale prices, but grid fees – which make up the bulk of your bill – were set in stone. You couldn’t optimize them, no matter how clever your setup was. That changes with time-variable grid fees. Now we’re talking fully flexible – where “every” part of the bill can respond to smarter usage.

And here’s where HEMS really struts its stuff: it sidesteps the few expensive hours when grid fees spike and shifts your usage to the low-demand windows – even if that’s just a couple of hours during the night. Because with most DSOs, the difference between cheap and costly isn’t huge in volume, but it is enough to make a dent in your bill if you hit the timing right.

Stack that on top of what you’re already saving from dynamic tariffs and you’re looking at a nice little bonus – €150 to €350/year just from grid fee optimization. The upper numbers greatly depend on the additional EV charging use cases you use.  

And the bonus? This shift isn’t just cheaper – it’s cleaner. By nudging consumption to off-peak hours, you’re more likely tapping into renewables, like solar at lunchtime or wind overnight. You help balance the grid and cut your costs. As Christian Agustin, gridX’s Product Manager HEMS said, “Dynamic tariffs support grid stability while cutting costs for the broader customer base.” So yep, that lazy overnight EV charge? It’s low-key heroic.

Bottom line: full flex is here and with HEMS in the mix, it’s a no-brainer. Your customers get an energy sidekick that tracks prices, shifts loads and delivers big energy savings without the need for daily tinkering. Smart, seamless and seriously worth it.

How intraday optimization adds a few hundred euros to your savings

If dynamic tariffs are like checking the weather report the night before, intraday optimization is like stepping outside and adjusting your umbrella in real time. It’s next-level flexibility  –  and yes, it can start saving money today while setting your customers up to earn tomorrow.

It’s like this, while dynamic optimization plays with day-ahead prices, intraday optimization means reacting to real-time price swings, often just minutes before delivery. Think: charging your EV or battery when prices crash at 3 p.m. due to excess solar and holding off when things spike at 7 p.m. because everyone's cooking dinner and watching Netflix.

And with gridX’s tech? That kind of reaction is automated, accurate and market-ready.

Real-time solar smarts: Charge when prices crash, pause when they spike

Let’s say there’s a midday solar oversupply and market prices drop – from the end customer’s perspective, it just looks like the system “knows” to charge the battery or preheat water when electricity is cheap. But behind the scenes, the HEMS is analyzing price signals, available flexibility and system constraints to decide if and when to act.

Later, when prices spike in the evening, it either holds off or taps into stored energy instead. No manual planning needed, no guesswork. It’s not just smart automation – it’s real-time optimization that’s already saving money today.

Batteries aren’t just for backup – they’re a real savings driver

Think your battery’s just there for backup? Think again. With the right HEMS setup, it becomes a serious earner – and the best part? It doesn’t even have to send a single kilowatt back to the grid.

Here’s how it stacks up:

A typical home with solar and a battery already benefits from day-ahead optimization – it’s a decent starting point. But switch to intraday optimization and the savings potential gets noticeably better, just by reacting faster to market price swings.

Now here’s where it gets spicy: expected updates under §9EEG could make grid fee structures a lot more attractive. That same setup? It could suddenly become a solid source of extra savings. Why? Because feeding electricity back into the grid won’t be such a financial headache anymore.

Until now, high fees and bureaucracy made exporting to the grid barely worth it. But with those barriers dropping and incentives rising, smart battery behavior – like charging when prices dip, discharging when they spike and feeding back in strategically – starts to actually pay off.

Even EV charging becomes a business case  

Even EV charging becomes a business case. It’s no longer just another item on your energy bill. With intraday optimization, it shifts from expense to opportunity.

Instead of charging during peak prices (think early evening), the HEMS automatically moves it to off-peak windows – usually overnight or when renewables flood the grid midday. No effort, no disruption. Just smarter charging behind the scenes.

As Christian Augustin, Product Manager HEMS, puts it:

“A poorly timed EV charge can be significantly more expensive than a smart, scheduled one – with no added benefit for the driver. With dynamic electricity tariffs, time-based grid fees and evolving regulations like §14a EnWG, end-customers need more than just hardware – they need intelligent control. A Home Energy Management System ensures their assets operate when electricity is cheapest, boosts solar self-consumption and keeps them compliant with the latest incentives. Whether it’s shifting a heat pump to midday solar, charging an EV overnight or responding to grid signals to unlock savings, the message is clear: it’s no longer just about installing hardware – it’s about delivering long-term, automated energy savings.”

Here’s how it works

gridX’s XENON dynamic optimization doesn’t just look at one system – it works across a fleet. Batteries, EVs and flexible assets from multiple households are pooled together into a single, controllable unit. This aggregated flexibility is then traded on the intraday market via market access providers – buying when prices are low or selling when they spike.

Once the deal is done, the energy or revenue is disaggregated and distributed back to individual systems. The result? Your home still benefits – without needing to run complex forecasts or optimization locally. It’s fleet-level intelligence with household-level impact.

Why this matters for installers and partners

Let’s face it – most homeowners don’t want to dive into grid fee structures or tariff schemes. They just want to know, “How much do I save?” And with a HEMS powered by gridX, the answer is clear – and impressively high.

Plus, it all comes in an easy-to-install, future-proof package that doesn’t just tick the compliance boxes – it also delivers real comfort. Minimal effort, maximum payoff.

This isn’t about tiny optimizations or theoretical gains. It’s about delivering real, trackable savings, all while keeping things running smoothly behind the scenes. With gridX, your customers can:

• Save up to €340/year by optimizing self-sufficiency and making smarter use of their own solar power.
• Cut power bills by €300–€550/year through dynamic tariff optimization and smart avoidance of time-variable grid fees
• Unlock up to €430/year by complying with §14a EnWG – without the hassle
• Save hundreds from EV charging at the right time
• Earn a few hundred more through intelligent battery control

All of that, from a system that reduces complexity, runs automatically and works with the hardware your customers already have.

While others are still selling solar-plus-storage and calling it a day, you’re offering solar-plus-strategy – clear value, real transparency and a smarter energy future.

That’s how you stand out in a crowded market.

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