What effects does a lack of energy efficiency have on Swiss mortgage?

Energy efficiency as a mortgage factor

Lack of energy efficiency has three direct effects on mortgage in Switzerland in 2026:

• Zins-Malus: Inefficient buildings (GEAK E-G) pay up to 0.25% to 0.50% higher interest rates as they do not receive “green mortgage” discounts.
• loan-to-value ratio: Banks subtract expected restructuring costs from market value, which massively increases equity requirements.
• Increased affordability: Higher imputed service charges reduce the scope for granting loans. Often, a mortgage is only granted against a contractually fixed restructuring obligation.

The interest rate difference: “Green Premium” vs. “Brown Discount”

In 2026, almost all major Swiss banks (cantonal banks, major banks and insurance companies) will differentiate their interest rates according to the energy quality of the property.

The eco-mortgage as a standard

While highly efficient buildings (GEAK A/B or Minergie) benefit from so-called “green mortgages” with interest discounts, owners of inefficient houses pay the standard rate or even a risk premium.

• Financial impact: With a mortgage of 1,000,000 CHF, an interest rate difference of just 0.3% means an additional burden of 3,000 CHF per year. Over a period of 10 years, we are talking about 30,000 CHF that will be “burned” simply because of the poor energy balance.
• risk premium: Banks argue that houses with fossil heating systems are more susceptible to future regulatory charges (CO2 taxes), which theoretically increases borrowers' probability of default.

Loan limits (LTV) and restructuring deduction

Loan-to-value (LTV) is the biggest hurdle for many buyers in 2026. Banks today no longer value an unrenovated house at the current market price, but apply an anticipated restructuring deduction.

The new evaluation logic

If a house is for sale for 1.5 million CHF but has a GEAK class G, the bank immediately calculates the necessary investments (heating replacement, façade insulation).

Example: The bank estimates restructuring costs at 200,000 CHF. Instead of paying the 1.5 million CHF, it bases its 80% ratio on an adjusted value:

As a result, the buyer must not only provide the usual 20% equity, but also cover the difference between the purchase price and the bank's (lower) loan value. This makes it impossible for many households to buy unrenovated properties.

The affordability calculation: service charges in focus

Imputed affordability is the bottleneck of every mortgage in Switzerland. It checks whether running costs account for a maximum of 33% of gross income.

Higher additional charges

Due to volatile energy prices and CO2 levies, banks adjusted their flat rates for service charges in the affordability calculation in 2026.

• standard houses: Here, 1% of the property value is often calculated for maintenance and service charges.
• Inefficient homes: Here, many institutes are now demanding 1.2% to 1.5% to reflect the high heating costs.
• The impact: A higher approach to service charges directly reduces the maximum loan amount that a family can cover with their income.

The risk of refinancing (end-of-term risk)

An often underestimated problem is the moment when a fixed-rate mortgage expires. In 2026, banks are required by law to reduce climate risks on their books.

No extension without GEAK

There are increasing cases in which banks refuse to extend a mortgage for class G buildings or impose strict conditions.

• Restructuring obligation: The bank only extends the mortgage if the owner simultaneously takes out a loan for a heating replacement or insulation.
• Increased amortization: Anyone who does not want to restructure is often forced to repay the mortgage more quickly in order to compensate for the falling value of the “brown asset.” This has a massive impact on monthly liquidity.

Stranded Assets: The creeping decline in value

Experts are increasingly talking about energy-deficient properties as “stranded assets.” These are assets that lose massively in value as a result of legal changes or market shifts.

Buyer psychology 2026

Since buyers know that they will have trouble with their mortgage if energy efficiency is poor, demand for such properties is falling.

• Market value discount: A poor GEAK rating now looks like a mortgage in the land register. It is a deferred liability that the buyer must assume.
• Future security: Anyone who restructs today secures access to tomorrow's capital market. A class A or B property is liquid in 2026 and can be refinanced at top conditions at any time.

Conclusion: Energy efficiency is a currency

What effects does a lack of energy efficiency have on mortgage? It makes them more expensive, smaller and riskier. In 2026, energy-efficient renovation is no longer a “nice-to-have” for idealists, but a hard prerequisite for healthy real estate financing.

In summary, anyone who owns or wants to buy an inefficient property must reckon with a “penalty interest rate” and higher equity requirements. The smartest owner due diligence today consists of investing the saved taxes from an energy-efficient renovation directly into optimising the building in order to secure its creditworthiness in the long term. The house of the future is not only warm, but above all financially viable.

glossary

• LTV (Loan-to-Value): The relationship between the mortgage amount and the market value (loan ratio) accepted by the bank.
• GEAK (cantonal building energy certificate): The standard for energy assessment in Switzerland.
• Climate Risk Scoring: Banks' internal assessment of how much a property could be devalued as a result of climate change or CO2 legislation.
• affordability: The calculation of whether a household can bear the costs of real estate (including imputed interest of usually 5%) in the long term.
• Owner due diligence: The proactive review of your own property for financial and regulatory risks.