Émile-Victor is a co-founder at Marker.io, a tech startup from Brussels. He’s reached an age where many of his friends have bought an apartment or are considering to buy one, and he’s wondering whether he should too. But he also knows about passive investing and he’s not quite sure what to do. Is he better off purchasing a home or using the money to invest in the markets? Which will be the best investment for him in the end? Let’s find out!

Two scenarios

Let’s compare two scenarios. In the first one, we purchase a house. We get a loan from the bank, make a down payment, pay our mortgage every month, and we have some maintenance and insurance expenses for the house. Because of inflation, house prices tend to rise over time. So we expect our house to be worth more than we paid for by the time we’ve fully paid off the mortgage.

In the second scenario, we opt to rent instead and use the remaining funds to passively invest. We invest all the costs that we make in the first scenario, i.e. the down payment, mortgage, and so on… in index funds. We calculated in “Why you should passively invest your savings” that we can expect a good yearly return when investing in index funds.

At the end of the mortgage period, we compare the value of our house from the first scenario to the value of our investments of the second scenario. Which one is higher?

The simulation

Before we start the simulation, we have to collect some data and fill in some numbers.

Scenario 1: buy a house

In the first scenario, we are buying a house. We make the following assumptions:

  • We are buying a 2-bedroom apartment in Brussels, Belgium that is being sold for €350,000.
  • The bank requires us to make a down payment of €70,000, which equals to 20% of the value of the house.
  • We have to take out a loan for the remaining €280,000. Based on our research, we can get a loan of 20 years at a fixed interest rate of 1.38%. This means that we have to make monthly payments of €1,336.
  • We pay a one-time registration tax at the purchase of the house (“droit d’enregistrement” in French or “registratierechten” in Dutch). The tax differs per region in Belgium but is set at 12.5% in Brussels, which equals to €43,750 for our apartment.
  • We spend about 1% per year on maintenance of the property, or €3,500. This is for renovations, fixing things around the house, and so on. This cost is subject to inflation and we use the Consumer Price Index to measure its yearly increase in price. In Belgium, the CPI has increased an average of 1.82% per year since 1994 [1].
  • Our home insurance costs €150 per year. This is also subject to inflation.
  • We pay a yearly property tax of €800, again subject to inflation.

Our costs of being a homeowner for the next 20 years, the duration of the mortgage, are regrouped in the table below.

Year Total yearly costs =
down payment +
mortgage +
registration tax +
maintenance +
insurance +
property tax
2021 €134,229
2022 €20,560
2023 €20,642
2024 €20,725
2025 €20,811
2026 €20,898
2027 €20,986
2028 €21,076
2029 €21,167
2030 €21,261
2031 €21,356
2032 €21,452
2033 €21,551
2034 €21,651
2035 €21,753
2036 €21,857
2037 €21,963
2038 €22,071
2039 €22,180
2040 €22,292
2041 €22,406

While we are paying back the mortgage, we expect that the value of the apartment will appreciate. We will then make a profit the day that we sell it.

In Belgium, changes in the price of houses are measured by the house price index. Following the numbers published by the Belgian government [2], we calculate that resell prices for apartments have increased an average of 4.22% per year since 2005. We project our €350,000 house to be worth €800,313 in 2041, 20 years from now.

Scenario 2: rent and invest

Now let’s look at the other scenario, where instead of buying a house, we rent for 20 years and passively invest what we would have spent on buying the house.

We estimate that the rent of a 2-bedroom apartment in Brussels is around €979 per month [3]. Due to inflation, rent prices are also expected to rise every year. In Belgium, the changes in rent prices are measured with the health index, which we calculate to have been growing annually by an average of 1.73% since 1994 [4].

We can now project how much our total costs will be for the next 20 years if we rent. Since we are not owners of the property, we don’t need to cover maintenance, insurance costs or property tax.

Year Monthly rent Total yearly costs = rent
2021 €979 €11,749
2022 €996 €11,952
2023 €1,013 €12,158
2024 €1,031 €12,368
2025 €1,048 €12,582
2026 €1,067 €12,799
2027 €1,085 €13,020
2028 €1,104 €13,245
2029 €1,123 €13,474
2030 €1,142 €13,706
2031 €1,162 €13,943
2032 €1,182 €14,184
2033 €1,202 €14,429
2034 €1,223 €14,678
2035 €1,244 €14,932
2036 €1,266 €15,190
2037 €1,288 €15,452
2038 €1,310 €15,719
2039 €1,333 €15,991
2040 €1,356 €16,267
2041 €1,379 €16,548

In this scenario, we are going to invest whatever we’re not spending. Every year, we are going to take the costs if we had bought a house, subtract the rent, and invest what is left. Let’s see how much that is.

Year Amount invested during year =
costs from scenario 1 -
costs from scenario 2
2021 €122,480
2022 €8,608
2023 €8,484
2024 €8,357
2025 €8,229
2026 €8,099
2027 €7,966
2028 €7,831
2029 €7,694
2030 €7,554
2031 €7,412
2032 €7,268
2033 €7,122
2034 €6,973
2035 €6,821
2036 €6,667
2037 €6,511
2038 €6,351
2039 €6,190
2040 €6,025
2041 €5,858

The first year, instead of making a down payment to the bank, we can invest a lump sum. During the following years, we invest whatever amount is left after rent. We invest in a globally diversified portfolio of index funds of 80% stocks and 20% bonds. A historical analysis tells us that this portfolio has earned an average annual return of 8.7% between 2005 and 2021.

We also need to take into account the transaction tax for every investment that we make. When investing in index funds, the transaction tax equals to 0.12% of the total amount invested.

The verdict

Finally, we have the data needed to answer the question. In 2041, 20 years from now, we estimate that:

  • the value of our house will be €800,313 (scenario 1)
  • the value of our investments will be €1,110,321 (scenario 2)

It looks like we end up in a better position if we rent and invest (scenario 2). Especially the downpayment and registration tax make a big difference, because an investment made early on compounds to spectacular sums of money over time. However, but the numbers are actually close enough that both scenarios are considered equally “good” investments. Indeed, a small change in one of the two most important parameters, the growth of house prices and the return of our index fund, can significantly change the result of the simulation. The most significant assumptions of our simulation are:

  • The resell prices of apartments keep rising at 4.22%. There are signs that Belgian houses are overvalued [6] because the average income of Belgians has not grown as much the house prices. If the increase in house prices slows down considerably, passive investing becomes a much better option.
  • The return on passive investing stays at around 8.7%. If the markets don’t do as well for the next 20 years, property will be a better investment.

There is too much uncertainty around these two parameters to make a confident prediction that you’ll be better off with one scenario or the other. However, the simulation has shown that you can’t go wrong with either investing in a house or investing in index funds.

Selling a house is harder than selling your investments

When viewing property as an investment, it’s important to consider that a house is much harder to sell than index funds. It usually takes several months from the moment you put the house up for sale to handing over the keys to the next owners. The process can even take years if the market is especially “cold”! It may also involve costs, for instance if you solicit the help of a real estate agent.

Furthermore, you cannot sell say 10% of your house. It’s all or nothing, you cannot sell part of your property.

Passive investing does not suffer from these constraints. Selling your investments is a matter of minutes instead of months. Also, the portion of the investments that you sell is completely up to you. In finance jargon, they say that index funds are more liquid than real estate.

The freedom that passive investing gives compared to investing in property is an additional consideration.

Run the simulation yourself

I did all the calculations on a Google Sheets spreadsheet. Feel free to make a copy and change the parameters according to your situation or country (go to “File” → “Make a copy”). The parameters that you can edit are indicated in green. Altering one of the parameters will instantly re-run the simulation.

Renting out our property

As a follow-up, we analysed treating our property as an investment by renting it out. We can then utilise the power of leverage to boost our return. Find out how it compares to passive investing.


Doing this exercise forced us to think about the important parameters underlying our decision. We saw that both the increase in house prices and returns from passive investing are the two main factors to take into account.

The simulation taught us that both passively investing and buying property are good investments. Because of the unpredictability of the future, it’s hard to predict at this point which one is really better for our wealth. The simulations show that the strategy of renting and investing is a better investment long term than buying a house as an investment. If you do decide to purchase a property then make sure you cover your mortgage payments and continue forming the habit of putting money away and passively investing it on the side to grow your nest egg and have diversification.

However, if we step away from viewing a house as an investment, having your own home provides a sense of independence and safety that passive investing cannot give you. Whatever happens in the world, you’ll have a place that is yours. This is an important criterion that cannot be reflected in a simulation.