Grand-Place
The UNESCO-listed market square at the centre of Brussels, three minutes on foot from the apartment.
Two kinds of people ask us about this, and they have opposite problems.
The first work remotely and are away most of the year. Their Brussels apartment is their home, and it sits empty for months at a time while they are somewhere else. The second bought in the centre as a second residence, use it a few weeks a year, and are wondering whether they should be renting it out the rest of the time.
Belgium taxes both of them on the same assumption: that a property you own is producing a benefit, whether or not anyone is in it.
I am not a tax adviser and this is not tax advice. Everything below is sourced, and the sources are linked, because the figures change and yours will depend on facts I do not have. Take the structure of the argument and check the numbers with an accountant.
The empty apartment is already taxed
If you own a Belgian property that is not your main residence and you do not rent it out, you declare its non-indexed cadastral income, and the taxable amount is the indexed cadastral income increased by 40%. Wikifin, the financial literacy service run by the FSMA, gives the worked example: a cadastral income of 1,000 euros, indexed at 2.3 and increased by 40%, gives 3,220 euros added to your other income. At a top marginal rate that is roughly 1,610 euros of tax, on an apartment that earned nothing.
That sits on top of the précompte immobilier, the annual property tax you pay regardless. And many communes levy their own tax on second residences that are neither occupied by the owner as a domicile nor rented, generally somewhere between 500 and 1,500 euros depending on where the property is.
So the baseline is not zero. An empty second home in Brussels has a running cost before you have decided anything.
Where the remote worker actually stands
If Brussels is your domicile and you are simply away a great deal, the picture is different and better than people assume. Your main residence is exempt from the cadastral income charge described above. Being absent does not by itself turn your home into a second residence.
What can change that is the domicile itself. If you deregister from your commune, or spend enough time elsewhere that another country claims you as a tax resident, the Brussels apartment stops being your main home and starts being taxed as the second kind. People who travel full time while working remotely tend to discover this the year after the fact.
The question worth asking before a long trip is not what your apartment costs while empty. It is where you are registered, and whether you intend to stay registered there. That answer drives everything else, and it is worth twenty minutes with an accountant before you go rather than a correction afterwards.
Why renting it out is heavier than it looks
The obvious answer to an empty apartment is to let people pay to stay in it. In the Brussels-Capital Region this is a regulated activity, and the regulation has been enforced with real energy over the last two years.
You need a registration number. Under the ordinance of 8 May 2014 on tourist accommodation, operating a tourist accommodation requires prior declaration to Brussels Economy and Employment, which issues a registration number. It applies from one night up to 90 consecutive days, whoever is staying, and it applies even if you only let for a few weeks a year. The number is tied to one operator and one address and cannot be moved to either another person or another property.
You owe the city tax, monthly. Brussels Fiscality levies a regional tax on tourist accommodation establishments. For 2026 the rate is 5 euros per unit per night for standard accommodation and 4 euros for accommodation at the host's home. You register the establishment on MyTax and file a declaration every month, within 31 days of the end of the month, including for the months when nobody came.
The income is split three ways. Belgian tax treats a furnished let as part property income and part income from the furniture. The default division is 60% immovable and 40% movable unless the contract says otherwise, with the movable share taxed at 30% after a 50% flat-rate deduction. Anything you charge for services, cleaning being the usual one, is treated separately again. Three categories, three treatments, one apartment.
And there is a line past which it becomes a business. Let enough, and regularly enough, and the tax authority can recharacterise the whole thing as professional income, which changes both the rate and your VAT position.
Enforcement is no longer theoretical. Brussels Fiscality recovered 2.8 million euros over the summer of 2025 and opened a regularisation campaign in 2026 aimed at several thousand undeclared operators. Airbnb can be required to remove listings that have no registration number.
Some of this is getting lighter. From 1 January 2027, owners letting their main residence will no longer need the town-planning conformity certificate, the safety check narrows to electricity, gas, heating and extinguishers with the cost capped at 150 euros and validity extended to eight years, and co-ownership is handled by informing the syndic. Registration and the monthly tax declaration both stay.
None of that makes short-term letting a bad decision. It makes it a decision with an administrative floor: a registration file, a monthly filing obligation that does not pause when the apartment is empty, and a tax computation in three parts. If you are letting sixty nights a year, that floor is a real share of what you earn.
What exchanging changes
A home exchange is not a let. Nobody pays you for the night, so there is no rental income, no tourist accommodation being operated for payment, and no city tax on a paid overnight stay. What you receive is GuestPoints, which you spend staying in someone else's home.
I want to be careful here, because this is the part where guides on other sites state things they cannot support. I have not found a published position from the Belgian tax authority on how GuestPoints are treated, and I am not going to invent one. What I can tell you is what we do: we exchange our own apartment, we take no money for it, and anyone whose situation is more complicated than that should put the question to their accountant in writing. If your exchange involves any cash changing hands, it is no longer the simple case and you should assume the letting rules are in play.
The shape of the argument is still easy to see.
For someone away most of the year, the apartment is going to be empty whether or not it earns anything. Exchanging turns those empty weeks into stays somewhere else, which is the thing they were going to spend money on anyway. The relevant comparison is not GuestPoints against rental income. It is GuestPoints against the accommodation budget for the trips they are already taking.
For a second-residence owner, the calculation is different and, I think, more interesting. You use the apartment a few weeks a year. Letting it the rest of the time means a registration file, a monthly declaration, a three-part tax computation, guests you have not met, and cleaning between each stay. It also means income, and for some people the income is worth all of that. But the empty-apartment tax described at the top of this article does not go away either way. It is a cost of owning, not a cost of leaving it empty.
So the question becomes what you want the property to produce. If the answer is money, let it, register properly, and price the administration in. If the answer is travel, points get you there with a much shorter list of obligations. The owners who are happiest with exchanging tend to be the ones who worked out that what they actually wanted from the second home was more time in other places.
The one thing worth checking first
If you own in a co-ownership, read the rules before you plan anything. Plenty of Brussels buildings restrict or forbid short-term letting outright, which settles the question before the tax treatment ever becomes relevant. Exchanges sit differently, since no commercial letting is happening, but building rules vary and the syndic is the person who knows.
Then check your domicile, then check your cadastral income. Those three facts decide most of this, and all three are things you can establish in an afternoon.
