Selling a house with a home battery: EPC and handover

A home battery does not improve your EPC label, and no official Belgian figure says how much it adds to the price. What it does add is a house that keeps running in a power cut and uses more of its own solar power. A buyer only pays for that when the system is documented, inspected and readable. Prepare a handover file before the house goes on the market.

You are selling a large house with solar panels, a heat pump and a battery that keeps everything running in a power cut. The estate agent asks for the EPC, and you expect the battery to help. One Belgian owner put the common belief this way on Reddit. "A better EPC generally means a better price when selling." The battery, however, does not move the label.

On the other side of the table, a buyer reads the file. In one Belgian sale, the inspection report listed 8 solar panels while 12 were on the roof. "I am going to put it to my notary," the buyer wrote. That is the hidden cost of a poor file: a premium system turns into a question mark, and a question mark turns into a discount.

The systems we build are meant to be read. In Kortenberg, a three-phase house has 30.8 kWh of batteries with full back-up. In Wetteren, the whole three-phase house runs through the battery. Our home battery systems can be followed in the free VRM app and portal: exactly the data a buyer wants to see.

Does a home battery improve the EPC of your house?

No. In Flanders a home battery has no impact on the EPC or the energy score. The Flemish government explains why: the EPC already assumes that all locally produced energy is used on site.

Solar panels therefore count in full. Their production is deducted from the primary energy use in the calculation. A battery only raises how much of that solar power you use yourself, which the EPC already assumes is 100%. You can ask your energy expert to mention the battery in the remarks field of the EPC, so candidate buyers see it.

Sources: vlaanderen.be (EPC residential unit), energie.wallonie.be (certificat PEB, quoi, quand, comment), Bruxelles Environnement (info-fiche on the PEB certificate, April 2022). In Wallonia, putting a house on sale without a valid certificate carries a fixed fine of 1,000 euro.

Is a home battery worth more when you sell your house?

A home battery adds value only when the buyer can see what it does and trust that it still works. No official Belgian source puts a figure on it, and we do not either.

Owners feel this themselves. One wrote on Reddit that the installation is "certainly an added value when you sell, but that is harder to pin down". Another advised against solar for a sale within 3 to 5 years, because you never get the money back.

For a large, premium home, the value lies elsewhere than in the price tag:

Should you leave the home battery in the house or take it with you?

Both are allowed. In Flanders, Fluvius accepts that you move your home battery, and a battery that stays is transferred to the new owner. Agree in writing which option applies before the sales agreement.

Source: Fluvius, home battery page. The same page adds a condition for older subsidies. If you received the Flemish home battery premium, the battery must stay connected to the distribution grid for at least 10 years. If not, you repay the premium.

Taking a battery along only makes sense when the new house can use it. Check the inverter, the phases and the space first. In ORES and Sibelga areas, ask your grid operator how a change of owner or a moved battery is reported.

What does the electrical inspection at a sale mean for a house with a battery?

An electrical installation installed after 1 October 1981 is deemed compliant at a sale, but only with a complete file. A new inspection is needed when the file is incomplete, the report is older than 25 years, or the installation was changed or extended.

The complete file is the situation plan, the single-line diagram and the inspection report. A home battery is exactly the kind of extension that must appear in it. In Flanders, Fluvius only accepts a battery registration with a valid AREI inspection. Our article on registering a home battery explains that inspection.

For an installation from before 1 October 1981, the seller has the installation inspected. The buyer then has 18 months from the deed to bring it in order and have it inspected again.

Do the warranty and the battery data pass to the buyer?

Not automatically. A battery warranty is a contract with the maker, and some are written for the first owner only.

The European warranty of the BYD Battery-Box Premium HVS and HVM is a clear example. It is given to the "Original Buyer": the person who buys the product for their own use and first puts it into operation. The document does not mention a transfer to a later owner. A claim also asks for the installation date and the invoice number.

So ask the maker in writing whether the warranty follows the house, and hand over the invoice and serial numbers. How a home battery warranty is built, and what voids it, is explained in our article on home battery lifespan and warranty.

The data are better protected by law. Since 18 August 2024, the battery management system of a stationary storage system must hold up-to-date data on its state of health and expected lifetime. The person who legally purchased the battery gets read-only access. One of the purposes the regulation names is evaluating the residual value and remaining lifetime.

What goes into the handover file of a home battery?

A good handover file lets the buyer check the battery without calling you. Put it together before the house goes on the market.

Where the battery stands and how it is protected also matters to a buyer and their insurer. Our article on whether a large home battery is a fire risk covers placement and insurance.

In what order do you arrange everything when you sell?

Start with the certificate and the file, not with the advert. In Wallonia the certificate must exist before the house is put on sale, and in Flanders the label must be in every advert.

Selling an off-grid or semi-off-grid house: what does the buyer need to know?

A buyer of an off-grid house buys an energy system along with the house. Explain how it is sized, what backs it up in winter and what it would take to connect to the grid.

Take our off-grid project in Lokeren: a new build without connections, with solar panels and an LFP battery system. A generator covers periods of high consumption or little sun. The whole system can be expanded later. In As, a fully off-grid home runs on solar panels, 30.8 kWh of batteries and a propane generator. How such a new build scores in the EPB is in off-grid new build and the E-level.

A buyer of such a house will ask these questions, so answer them in the file:

• How was it sized? The consumption it was designed for, and how the winter is covered: the generator, its fuel and its running hours.
• What would a grid connection take? Some buyers want the grid as a safety net. The cost and the options are in our article on grid extension cost versus a battery.
• Who maintains it? The installer, the maintenance history and the monitoring access.
• What are the limits? Which appliances the system was not designed for, such as a second heat pump or fast EV charging.

An owner who weighed going off-grid saw the value of a connection for a future buyer. In his words, the grid "infrastructure is in place should you or a future buyer want to be back on the grid". A buyer of a house without any connection has to look at that separately. Our article on a building without a grid connection explains what that means. For what we build for off-grid homes, see our off-grid systems.

Buying a house with a home battery: what should you check?

Check the paperwork first and the hardware second. A battery without a file costs you time after the deed.

How do we help when a house with a home battery changes hands?

We revise the installed battery, make its data readable and set up the back-up for the next owner. Our team includes three certified battery experts.

1. Step 1: We revise installed batteries and carry out maintenance and repair work on battery systems that are already installed.
2. Step 2: You and the next owner follow production, consumption and the battery in the free VRM app and portal.
3. Step 3: We connect the main systems of the house separately to the battery. In a power cut, the household does not come to a standstill.
4. Step 4: For the new owner, we check which extension or new home battery with back-up fits their use. Think of a heat pump or a car charger.

Not every battery should stay. At the real end of its life, a lithium home battery goes to recycling. In our Battery Disassembly Center we take apart lithium batteries from cars, bicycles and home batteries. Second life or recycling: that choice is explained in what happens to a home battery at the end of its life.