IOS tool to model Swiss Buy vs. Rent math (Eigenmietwert, ETF opportunity cost, indirect amortization) – would love your feedback!

[deimos1969]

Hi everyone,

While running the numbers on whether to buy property or keep renting in Switzerland, I found it difficult to get a complete picture using standard bank calculators or generic spreadsheets. They often oversimplify or completely miss the specific Swiss tax and mortgage mechanics.

I wanted to model exactly how the math works out over 10-30 years, specifically accounting for: • Eigenmietwert & Tax Shifts: How the imputed rental value shifts your marginal tax bracket vs. the deductions from mortgage interest and maintenance. • True Opportunity Cost: Comparing tying up down-payment equity in bricks vs. compounding it in an ETF (like VT or MSCI World). • Swiss Amortization: Factoring in the 2nd mortgage repayment schedule (down to 66% LTV within 15 years) and comparing the net-worth impact of Direct vs. Indirect (Pillar 3a) amortization. • Actual Running Costs: Comprehensive maintenance rules (0.5% - 1%) and ancillary fees (Nebenkosten).

I ended up building a dedicated native iOS app called Buy vs Rent CH to handle these variables side-by-side and calculate the exact break-even point.

Since this community is incredibly knowledgeable about Swiss personal finance, I’d love to get your feedback to stress-test it. I want to make sure the underlying logic is rock solid. You can find it on the App Store by searching "Buy vs Rent CH".

I'm particularly curious:

1. How do you currently factor long-term ETF opportunity cost into your own homebuying calculations?
2. What obscure Swiss tax edge cases am I probably missing in my engine?

Thanks in advance for any feedback!

 

[Baptiste Wicht]

Since the imputed rental value is going away, you might want to model a hybrid model where it currently starts with the rental value and then it disappears.

How do you currently factor long-term ETF opportunity cost into your own homebuying calculations?

I took 25% of the house value as an opportunity cost. You should not forget to integrate all the fees as opportunity cost.

What obscure Swiss tax edge cases am I probably missing in my engine?

Did you take the property tax value (usually expressed in a per thousand of the value of the house)?

 

[thomasfrank]

Hi everyone,

While running the numbers on whether to buy property or keep renting in Switzerland, I found it difficult to get a complete picture using standard bank calculators or generic spreadsheets. They often oversimplify or completely miss the specific Swiss tax and mortgage mechanics.

I wanted to model exactly how the math works out over 10-30 years, specifically accounting for: • Eigenmietwert & Tax Shifts: How the imputed Basketball Bros rental value shifts your marginal tax bracket vs. the deductions from mortgage interest and maintenance. • True Opportunity Cost: Comparing tying up down-payment equity in bricks vs. compounding it in an ETF (like VT or MSCI World). • Swiss Amortization: Factoring in the 2nd mortgage repayment schedule (down to 66% LTV within 15 years) and comparing the net-worth impact of Direct vs. Indirect (Pillar 3a) amortization. • Actual Running Costs: Comprehensive maintenance rules (0.5% - 1%) and ancillary fees (Nebenkosten).

I ended up building a dedicated native iOS app called Buy vs Rent CH to handle these variables side-by-side and calculate the exact break-even point.

Since this community is incredibly knowledgeable about Swiss personal finance, I’d love to get your feedback to stress-test it. I want to make sure the underlying logic is rock solid. You can find it on the App Store by searching "Buy vs Rent CH".

I'm particularly curious:

1. How do you currently factor long-term ETF opportunity cost into your own homebuying calculations?
2. What obscure Swiss tax edge cases am I probably missing in my engine?

Thanks in advance for any feedback!

For me, the ETF opportunity cost is one of the biggest factors. I’d compare the expected net ETF return against the property’s realistic appreciation after maintenance, taxes, and transaction costs. I’d also pay close attention to how Pillar 3a amortization affects the tax calculation, since that can change the break-even point quite a bit.