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Interactive

See what damp is doing in a home like yours

Pick a property and a ventilation system, then watch the damp air leave and fresh air arrive. It is an illustration, not a survey — but it shows exactly how each system works.

  1. 1Your home
  2. 2What to fit
  3. 3Watch it work

1. What sort of home is it?

Tap the one that looks most like yours. It does not have to be exact.

2. What would you like it to do?

Four ways to fix it, smallest job first. If you are not sure, use the button underneath — we will pick a sensible starting point for your home.

2-Bed Terraced / Semi · with loft access · 78% humidity · mould forming on the cold-bridge areas

Pick a property type and a ventilation system first.

Tell us more about your home Optional — it makes the "before" match what you actually see
What is it actually like in the house?
Condensation on the windows in the morning?
Any black mould showing?
How many people live here?
Washing dried indoors?
73%

Condensation on windows and cold walls. Mould can take hold here.

Estimated from your answers, not measured. On a survey we take a real reading in each room.

I have a hygrometer and know the reading
Mould grows where warm, damp air meets a cold surface.

Illustrative only. This shows how each system moves air through a home of this shape — it is not a Part F calculation and not a system design. A site survey is the only way to size a system properly.

Not sure where to start?

Send us a message with what you have noticed at home. We will tell you honestly whether you need a survey, a system, or neither.

Trained on the systems we install

Certificated — and here they are

Most trade sites show you a row of logos. These are the actual certificates, both sat in August 2026. Tap either one to read it, or download the PDF.

  • Company no. 12092552 Registered in England & Wales. Trading as Cavalli Ventilation since July 2019, and in ventilation since 2003.
  • Airflow measured on every install A calibrated anemometer at the grille, recorded and handed over. The only figure that counts is the one measured in your room.