Passive House / Performance
Passive House
design.
With Alexandru Zorlescu, Certified Passive House Designer. Comfort and energy performance, considered alongside architecture from the first sketch.
Discuss your project ↗Your brief. A clear scope.
We work from Corbeanca on house projects in Bucharest, Ilfov and across Romania. The starting point is your site and the comfort you want: daylight, summer shading, fresh air and how the rooms will be used.
The proposal defines the architectural stages, coordination with structural and building-services designers, energy assessments and agreed site investigations. If building certification is an objective, we clarify the assessment process, the evidence required and each participant’s role.
Discuss your Passive House project ↗Before we start.
When should we discuss the energy target?
At the brief stage, before fixing the building form and window sizes. Orientation, shading, the envelope and ventilation need to work together.
What should I send for an initial conversation?
The site location, available drawings, photographs, the approximate floor area and your budget and programme. For an existing house, include the problems you have noticed and any available energy or investigation reports.
Does the designer’s qualification certify my house?
No. Alexandru Zorlescu’s Certified Passive House Designer qualification concerns the designer. Certification of a particular building requires a separate assessment and project-specific evidence. We agree the intended outcome and responsibilities at the outset.
From design to measurement
Performance, checked on site.
How does the building behave beyond its drawings? On-site investigations connect the design to what we observe and measure.
Thermography, temperature and moisture measurements, thermal transmittance assessment and airtightness testing help investigate the envelope — from windows and walls to roofs and plinths.
Photographs from investigations carried out by Alexandru Zorlescu.
01 / Field notes
Airtightness · Blower Door
A fan mounted in the doorway creates a pressure difference to assess air leakage through the building envelope.
02 / Field notes
Thermography · surface temperatures
The thermal image helps locate temperature differences and areas that need closer investigation.
03 / Field notes
Thermal transmittance · dedicated probes
Contact probes on the wall support a U-value assessment, together with indoor and outdoor temperature readings and the measurement method.
04 / Field notes
Reading the test parameters
The instrument display during a Blower Door test. Readings are interpreted within the complete test record and its conditions.
From observations to decisions
Locate. Understand. Check again.
We investigate possible thermal bridges, material moisture and air infiltration paths. Anemometer readings can help locate air movement at critical junctions. We choose the instruments and method for the question being investigated.
We correlate the readings with the drawings, the construction stage and the test conditions to discuss the next steps.
Discuss your building ↗Energy assessment / Three stages
From measurements to an intervention plan.
A process that connects field evidence, energy calculations and your investment decisions.
01 / Field investigations
We measure to understand the building.
Depending on the building and the assessment objective, we combine thermal imaging, temperature and material moisture measurements, and thermal transmittance evaluation using dedicated sensors. Blower Door testing assesses airtightness; anemometer readings help locate air movement at critical points. CO₂ monitoring provides further information about ventilation and occupancy.
For you: You gain a documented picture of the areas that need attention.
02 / Energy modelling
Measurements inform the analysis.
We relate the available measurements to the building geometry, materials and systems. designPH supports 3D modelling and preliminary energy evaluation; relevant data is exported to PHPP to develop the calculation and compare improvement scenarios.
For you: You can compare the estimated effects of different measures before investing.
03 / Intervention plan
Clear priorities, matched to your budget.
Based on the investigations and calculations, we propose an intervention plan suited to the building, your objectives and the available budget. We prioritise measures and discuss their sequence, so work can be phased coherently.
For you: You understand what to address first, what can follow and how the measures work together.
01 / The building as a whole
Comfort starts with the envelope.
Five principles, considered together from the first sketch. Explore their place in a simple building section.
01Continuous insulation
A thermal layer around conditioned spaces limits heat transfer.
02High-performance windows
Glazing, frames and installation work together. External shading helps control summer solar gains.
03Airtightness
Carefully detailed joints limit uncontrolled airflow through the envelope.
04Reduced thermal bridges
Thermal continuity also matters at corners and wall-to-floor junctions.
05Heat recovery ventilation
Controlled ventilation renews indoor air while recovering part of the outgoing air’s heat.
Principles: Passive House Institute · PHI — how a Passive House works
Inside the system
Fresh air. Recovered heat.
In a plate heat exchanger, incoming and extracted air travel through separate channels. Heat passes through the exchanger surface, prewarming the incoming air in winter.
The drawing shows heat transfer between the streams, not the recirculation of extracted air. System sizing, filtration and maintenance are part of the design and operation.
Passipedia — ventilation principles ↗Original diagrams by Zorlescu Architecture. Explanations informed by educational resources from the Passive House Institute and Passipedia.
An objective. A calculation. A result.
The design objective guides the project. A calculation or test provides evidence associated with a method, a stage and specific conditions. Building certification is a separate assessment against the applicable criteria.
Alexandru Zorlescu is a certified Passive House designer. This professional qualification does not certify an individual building. M22 is presented through architecture and photographs; it is not presented as a certified Passive House.
About the architect ↗Services and investigation
Understand. Measure. Refine.
New buildings and renovation
We develop architectural projects with energy performance objectives for both new buildings and existing homes. The envelope, thermal bridges, airtightness and building services are considered together with comfort and the quality of space.
Energy modelling · designPH and PHPP
designPH supports three-dimensional modelling and preliminary energy evaluation. Its data can be exported to PHPP for further calculation. The quality of the assessment depends on the input data, the method and the verification of the model.
Thermal imaging
Thermography helps locate surface temperature differences and investigate possible discontinuities in the envelope. Results are interpreted in relation to weather, temperature difference, surface properties and the inspection conditions. A thermogram alone does not establish the cause of an anomaly.
Temperature, humidity and material moisture
Measurements help document the conditions in a space and the behaviour of materials. Evaluating thermal transmittance requires suitable sensors and a defined method; a general temperature and humidity reading is insufficient.
Airtightness testing · Blower Door
A pressure test evaluates air leakage through the building envelope. The report identifies the method, building volume, test conditions and results. Testing can inform work during construction and the final performance assessment.
CO₂ monitoring and operation
Monitoring CO₂ concentration, temperature and humidity can help assess ventilation and patterns of use. Readings are interpreted with the occupancy, sensor location and measurement period in mind.
A defined scope of assessment
Energy analysis for design is distinct from a regulated energy audit or an energy performance certificate. Where those documents are required, the relevant authorised specialist is involved. Building certification is also a separate assessment.
The scope, sequence and deliverables are defined for each project. References reviewed on 9 September 2026: PHI — Planning tools · Passipedia — Blower Door · Legea 372/2005
M22 / From practice
Between house and garden.
The photographs follow the relationship between the house, its openings and the garden.
See the M22 photographs ↗