01
Minergie
strict requirements for heat protection
but no temperature guarantee
UrbanHome · Living guide
Too hot despite Minergie? How to spot overheating risks before moving in
A Minergie label is a strong indicator of energy efficiency and comfort – but it does not guarantee that every apartment stays cool on every summer day. Window area, external blinds, orientation, night-time cooling, building services and the apartment’s position within the building also matter.
Author: Nikita von Niederhäuser, UrbanHome real estate expert Updated: · Reading time: approx. 17 minutes
02
Cross-ventilation
particularly effective at night
two façades are ideal
03
External blinds
stop solar energy before it reaches the glass
indoor curtains are less effective
04
Urban climate
more tropical nights expected
night-time cooling is becoming more important
Minergie & heat
Efficient.
Comfortable.
Not automatically cool.
The Swiss building standard sets high requirements for energy efficiency, the building envelope, air exchange and comfort.
Check summer comfort in detail
01
Minergie does not mean air conditioning
In 2026, Minergie explicitly states that its requirements for heat protection go well beyond legal standards and that, on hot days, Minergie buildings stay considerably cooler on average than conventional buildings. [1]
02
The individual apartment matters
The label does not promise a specific room temperature in every apartment. Summer comfort depends on building design and how occupants use the space.
03
Several systems must work together
External shading, night ventilation, cross-ventilation, ventilation bypass and, where appropriate, GeoCooling or active cooling work together. [1]
A better question during the viewing
Do not just ask “Is the building Minergie-certified?” Ask: “How exactly does summer heat protection work in this apartment?”
Why does it still get hot?
Good insulation alone does not prevent overheating
Even a very well-insulated apartment can absorb heat. The problem arises when a lot of solar energy enters during the day but not enough heat escapes at night.
01
Glazing
Large west- or east-facing windows
Especially problematic without effective external shading.
02
Floor
Penthouse and attic apartments
High solar exposure can be especially significant with large glazed areas.
03
Wind sensor
Blinds rise automatically
Automatic blinds may open in windy conditions exactly when shade is needed.
04
Ventilation
No cross-ventilation
Windows on only one side can make effective night-time cooling difficult.
05
Noise
Windows closed at night
Road or rail noise can make night ventilation impractical.
06
Building services
No effective night cooling
A ventilation system alone does not guarantee enough heat removal.
07
Indoor spaces
Internal heat gains
Appliances, lighting and many people generate additional heat.
08
Cooling
No passive or active cooling
In especially exposed apartments, lack of cooling can further reduce comfort.
Four key elements
SwissEnergy identifies optimised window areas, external sun protection, thermal mass and night-time cooling as key ways to prevent summer overheating. [2]
8 overheating risks
Warning signs to check before moving in
These eight points quickly show how well an apartment can withstand summer heat.
Favourable
Good conditions
What supports summer comfort
Working external Venetian blinds or shutters
Moderate window areas and structural shading
Windows in two directions and a quiet location at night
Middle floor
Summer bypass or night-cooling function clearly explained
GeoCooling, free cooling or an effective cooling system
Trees, shade, greenery and good airflow
North-/east-facing bedroom with windows that can open at night
Warning sign
Risky combinations
Take a closer look here
Only indoor curtains or blinds that constantly retract
Floor-to-ceiling west-facing glazing without shade
Just one façade or heavy night-time noise
Penthouse or top floor with extensive glazing
“Ventilation available” without an explanation of summer operation
No cooling despite high solar gains
Asphalt, airless courtyard or dark façades
West-facing bedroom with evening sun and a noisy street
Windows & orientation
West can be more critical than south
The simple rule “south = hot” is too simplistic. In summer, the sun is low in the morning and evening.
W
West-facing windows
Evening sun just before nightfall
Large west-facing windows can be problematic because low evening sun heats rooms just when they should be cooling down.
S
South-facing windows
Often easier to shade
Balconies, overhangs or horizontal sunshades can be relatively effective at blocking high summer sun.
Check bedrooms especially carefully
Evening sunshine in the bedroom is critical because it warms the room again just before bedtime.
External blinds
One of the most important points during a viewing
Minergie identifies movable external sun protection as a particularly effective measure. Ideally, it should be controlled according to sun position and temperature; wind resistance is also important for automated systems. [1]
01
Automatic wind control
Do the blinds automatically rise when it is windy?
02
Wind threshold
At what wind speed does automatic retraction activate?
03
Staying closed
Can they stay closed for long periods despite sunshine?
04
Manual override
Can residents override the automation?
05
Technical condition
Are the motors and slats fully functional?
Indoor curtains are not an equivalent substitute
They reduce glare, but only stop solar energy after it has already passed through the glass.
Night-time cooling
Can the apartment release heat at night?
According to Minergie, night-time cooling is one of the most efficient ways to remove heat stored in a building. [1]
01
Ideal
True cross-ventilation
Windows on opposite façades or façades facing different directions are most effective.
02
In practice
Is night-time ventilation really possible?
Road traffic, trains, restaurants, mosquitoes, burglary risks or high outdoor temperatures can severely restrict night ventilation.
Comfort ventilation
A ventilation system is not necessarily air conditioning
Comfort ventilation primarily provides fresh air and controlled air exchange. It is not necessarily air conditioning. [2]
01
Summer bypass
Is there a dedicated summer mode?
02
Cool night air
Can the system deliberately use cooler outside air at night?
03
Airflow rate
How much air is actually exchanged?
04
Night mode
Does the system automatically change operation at night?
05
Opening windows
Can windows be opened in addition to using the ventilation system?
Building cooling
Understanding GeoCooling, underfloor systems and active cooling
Cooling may be part of the design in newer Minergie projects. Minergie identifies GeoCooling via geothermal probes as a particularly efficient solution. [1]
01
GeoCooling
Use cooling from the ground
Geothermal probes can use the ground’s comparatively cool temperatures to provide gentle indoor cooling with little energy.
02
Surface cooling
Floor or ceiling
Some systems distribute cooling through floors or ceilings. They respond differently from conventional air conditioning.
Questions
Do not just ask about the heat pump
What you should know specifically
Is the apartment actually cooled?
Which surfaces provide cooling?
What target temperatures are planned?
Can cooling be controlled individually?
What additional costs arise?
Important
Not an air conditioner
Gentle cooling works differently
Floor cooling behaves differently from conventional air conditioning: it cools gently and usually cannot dehumidify the air.
Top floor & penthouse
Take a closer look at the top floor
A penthouse or attic apartment is not automatically a heat trap, even without conventional air conditioning. Good insulation, low solar gains, external shading and cooling can provide excellent comfort.
01
Glazing
Roof and west-facing windows
Check their size and orientation, and whether every heavily sun-exposed window has external shading.
02
In practice
Ask about actual summer temperatures
How hot did the bedroom get during the last heatwave lasting several days?
Urban climate
Heat.
Tropical nights.
Noise.
In cities, not just the apartment itself matters, but also the climate just outside its windows.
Night cooling is getting harder
01
More tropical nights
The CH2025 climate scenarios predict significantly more hot days and tropical nights.
02
About five times more for Zurich
In a world about 3 °C warmer globally, Zurich is expected to experience on average around five times as many tropical nights . [5]
03
Hottest day around 4.4 °C warmer
Across Switzerland, the hottest day of the year would be around 4.4 °C hotter on average than in 1991–2020.
Urban locations can limit night cooling
Buildings and sealed surfaces store heat and release it at night. At the same time, traffic and other noise sources may prevent opening windows.
Viewing
In
15
minutes: the heat test.
A few simple tests can substantially improve your assessment of an apartment’s summer heat risk.
Ideal
Warm late afternoon
01
Timing
View when it is warm and late
Ideally, on a sunny day between about 4 p.m. and 7 p.m.
02
Temperature
Bring your own thermometer
Measure the living room and bedroom, but not right next to the window.
03
Blinds
Test every blind
Close them completely, then reopen them.
04
Windows
Test airflow
Open the windows and check whether true cross-ventilation is possible.
05
Noise
Stay silent for one minute
With an open window, assess whether night ventilation would be realistic.
06
Bedroom
Assess this room first
Night-time temperature is especially important for comfort.
07
Technology
Ask for an explanation of the system
Ventilation bypass, cooling, heat pump and room controls.
08
Experience
Ask the previous tenant specific questions
“How hot did it get in July/August?” is often more informative than “Is the apartment pleasant in summer?”
One measurement is not enough
What matters is the temperature pattern over several warm days, especially cooling at night.
12 questions
Questions to ask property management or the previous tenant
01–06
Sun & ventilation
How does the apartment behave?
Which rooms receive direct evening sunshine?
Are external blinds installed on all highly exposed windows?
Are blinds automatically controlled by sun and wind?
Can the automatic controls be overridden manually?
Is cross-ventilation possible at night?
How noisy is it with open windows between 10 p.m. and 6 a.m.?
07–12
Technology & experience
What is known from actual operation?
Does the ventilation system have a summer bypass or night-cooling mode?
Is GeoCooling, free cooling or active cooling available?
Can cooling be controlled by apartment or by room?
What were the highest temperatures recorded last summer?
Have residents complained about overheating?
Have sun protection or cooling been retrofitted since construction?
Documents
Useful documents for a Minergie building
You can ask technical questions about a high-quality new apartment. Not every property manager will release all planning documents, but available records may provide valuable clues.
01
Minergie certificate
Certificate or building identification number.
02
Sun protection
Description of the existing sun protection system.
03
Operating instructions
Documentation for blinds and ventilation.
04
Summer bypass
Information about the ventilation system’s summer mode.
05
Free cooling
Description of GeoCooling or free cooling.
06
Summer comfort
Summer comfort or heat protection assessment for the project.
07
Windows
Information on orientation and glazing.
Swiss tenancy law
Too hot after moving in: what rights do tenants have?
For rented apartments in Switzerland, there is no generally applicable statutory maximum indoor temperature. However, significant overheating can constitute a defect in the rented property. [3]
01
Document
Measure temperatures over several days
Duration, severity, outdoor temperatures and the actual impact on the occupants all matter.
Record temperatures
Report overheating in writing
Record the time period and affected rooms
02
Measures
No general right to air conditioning
Where there is a relevant defect, the landlord must consider suitable and proportionate remedies, such as external blinds, roller shutters or heat-protection window films.
Do not generalise from a Federal Supreme Court case
The Federal Supreme Court case 4A_581/2016 cited by the tenants’ association concerned persistent overheating even outside heatwave days. A rent reduction of 7.5% was upheld for temperatures 3–5 °C too high. This is an individual case, not a general percentage for summer heat. [3]
UrbanHome search
Find Minergie and rental apartments on UrbanHome
When viewing new-build and Minergie properties, look beyond the construction year and energy efficiency: explicitly assess summer heat protection.
01
Apartment search
Search rental apartments →
Compare current rental apartments
Use UrbanHome’s rental apartment search and assess summer comfort when viewing properties of interest.
02
Summer check
Five checks before saving a listing
Check the floor, window orientation, external sun protection, cross-ventilation and available cooling.
Checklist
Spot overheating risks before signing a lease
Try to check these twelve points before signing, especially if the apartment is exposed to summer heat.
01–06
Building & windows
Basics checked
Minergie standard and building systems clarified
Living room and bedroom orientation checked
External blinds tested on all critical windows
Automatic wind controls and manual operation understood
Cross-ventilation tested in practice
Night-time noise assessed with windows open
07–12
Technology & experience
Summer operation understood
Summer bypass of ventilation explained
GeoCooling, free cooling or active cooling clarified
Penthouse or attic location specifically assessed
Previous tenants asked about actual summer temperatures
Viewing carried out on a warm late afternoon where possible
Bedroom assessed separately
Sources
Sources and reference dates
The technical information is based on Minergie, SwissEnergy and the CH2025 climate scenarios. The legal assessment follows current information from the Swiss Tenants’ Association.
Sources and legal status checked on .
- Minergie: heat protection – requirements, shading, night cooling and GeoCooling
- SwissEnergy: energy-efficient new buildings and preventing summer overheating
- Swiss Tenants’ Association: Too hot in the apartment? Tenants’ rights (18 June 2026)
- MeteoSwiss: Urban heat and future tropical nights
- NCCS: Climate CH2025 – Heat and tropical nights
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04
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Answered directly
Frequently asked questions about Minergie and summer heat
The most important answers, explained concisely.
10
Questions & answers
Yes. Minergie has high heat-protection requirements, but actual comfort also depends on window area, shading, night ventilation, location, occupancy and available cooling.
No. Comfort ventilation primarily provides controlled air exchange and fresh air. Whether and how it cools at night depends on the specific system.
Large, unshaded west-facing windows can be critical because low evening sunshine heats rooms substantially just before nightfall.
Yes. External shading blocks much of the sun’s energy before it passes through the glass and is significantly more effective against overheating.
GeoCooling uses the ground’s comparatively cool temperatures, often via geothermal probes, to cool rooms gently with little energy.
Ideally, on a sunny, warm late afternoon. A second check in the evening shows whether the rooms cool down again.
There is no generally fixed maximum for summer heat. However, serious and persistent overheating may constitute a rental defect in individual cases.
No, there is no general entitlement. However, if there is a relevant defect, the landlord must consider suitable and proportionate measures.
No type is guaranteed. Good external shading, limited solar gains, cross-ventilation, quiet nights and a well-designed cooling option for highly exposed new builds are generally favourable.
Use UrbanHome’s rental search to compare current apartments and check heat protection specifically during viewings.
UrbanHome guides
View more guides about living →
Key takeaways
Conclusion: Minergie is an advantage, but the individual apartment still matters
Minergie significantly reduces the risk of summer overheating, but does not replace checking the specific apartment.
Five points are particularly revealing for prospective tenants: effective external blinds, limited solar gains, true night-time and cross-ventilation, bedroom orientation and a clearly explained summer mode for the building systems.
Testing these points on a warm late afternoon and asking about actual temperatures during the last heatwave helps identify many risks before signing.
Apartment search & summer comfort
Find an apartment with good summer comfort
Compare current rental apartments on UrbanHome. Before applying, check the orientation, floor, external blinds, ventilation and possible cooling of properties that interest you.
Compare rental apartments
Check summer comfort
Avoid overheating risks