One engineering-led journey, from investigation to certification.
Retrofit IQ is a building performance consultancy, not a general contractor. Each of our services is a stage in a single, connected engineering process — measure, model, design and certify — led by a Certified Passive House Designer and grounded in building physics, PHPP calculations and engineering analysis.
Engineering decisions based on calculations, not assumptions
Most building work starts with a product recommendation. We start with evidence and physics. By investigating first, modelling the building and verifying the design before any work begins, we de-risk the whole project — so you invest with confidence rather than hope.
We start with measured evidence — heat loss, moisture, air leakage and fabric condition — never assumptions.
We turn that evidence into an engineered design using building physics and PHPP energy modelling.
We prepare the evidence and coordinate the independent Passive House Certifier through to certification.
How each service leads to the next
From investigation through engineering design to certification support — a clear path, with one point of responsibility.
The complete engineering toolkit
Measured diagnosis of heat loss, damp, mould, air leakage and ventilation — the evidence base for everything that follows.
Learn moreProfessional building physics modelling and engineering calculations to predict how your construction will perform before any work begins.
Learn moreIndependent assessment of whether your building fabric is ready for an efficient, low-running-cost heat pump.
Learn moreUltra-low-energy design to the Passive House standard, engineered from first principles.
Learn moreAccurate Passive House Planning Package modelling, built and interpreted by a Certified Passive House Designer.
Learn moreThe Passive House retrofit standard — a staged, engineering-led path to a high-performance existing home.
Learn moreEvidence preparation and coordination with your independent Passive House Certifier, end to end.
Learn moreEngineering & design partner — not the certifier
Retrofit IQ provides the engineering, modelling and design. The formal Passive House and EnerPHit certification is carried out by an independent, accredited Passive House Certifier. We coordinate with the appointed certifier on your behalf — so you get rigorous engineering and a smooth certification, with one point of responsibility.
Not sure where your project starts?
Tell us about your building and we'll point you to the right stage of the journey — no obligation.