Ventilation that responds to what’s happening in the house, rather than running regardless.
Sensor-driven airflow that rises and falls with the moisture in the room.
Homes produce moisture constantly — cooking, showering, drying clothes, and simply breathing. In a house with poor ventilation that moisture has nowhere to go, and it shows up as condensation on windows, damp patches in corners and mould on cold surfaces.
Demand control ventilation deals with it intelligently. Fresh air enters through humidity-sensitive inlets, usually set into window frames or external walls in living rooms and bedrooms. These open further as indoor humidity rises and close down as it falls.
A central extract unit, ducted to the wet rooms, draws stale, moist air out continuously at a low rate and boosts when the sensors detect a spike. Because airflow is modulated rather than constant, DCV ventilates when it’s needed without over-ventilating the rest of the time — which is where the heat saving comes from compared with fixed-rate extract systems and permanently open wall vents.
The practical mechanical option for a house that is already finished.
DCV is the most practical mechanical ventilation option for existing homes, and the reason is ductwork.
MVHR needs supply and extract ducts running to every room. In a house with finished floors and ceilings, installing that is a major intervention. DCV only ducts the wet rooms, with the supply side handled by inlets in window frames or walls — so it can be installed in an occupied house without tearing it apart. It’s the right system when:
From insulation to heat pumps, ventilation and more. Improve comfort, lower bills and increase your BER rating.
New builds, extensions and deep retrofits, fully managed from design and planning through to construction and completion.
High-quality solar panel systems for homes, farms and businesses. Lower energy costs and gain energy independence.
Energy upgrades and construction solutions for commercial, agricultural and public sector projects.
This connection is worth being explicit about, because it catches people out.
An old, leaky house ventilates itself accidentally through gaps and draughts. It’s wasteful and uncomfortable, but the moisture goes somewhere. Insulate and draught-proof that house without addressing ventilation, and the moisture stays in — and condensation and mould appear in a home that never had them before.
That’s not a fault in the insulation. It’s a ventilation strategy that was never designed. Every insulation project we carry out includes a ventilation assessment for exactly this reason.
Installation is typically one to two days depending on the number of wet rooms and duct routes. The central unit goes in the attic or a utility space with access for servicing. Maintenance is minimal — periodic filter cleaning or replacement and a check of the extract terminals.
No. It modulates airflow to what’s needed, which is considerably less heat loss than permanently open wall vents or a constantly running extract fan.
Existing background vents are assessed as part of the design — in many cases they’re replaced by the controlled inlets. Don’t block anything until the system is designed and commissioned.
The central unit is remote from living spaces and runs at low speed most of the time. Correctly sized ductwork keeps it quiet.
DCV suits existing homes that aren’t being made airtight. MVHR suits airtight new builds and deep retrofits, and recovers heat, which DCV doesn’t. The building decides.
It will remove the conditions that cause it. Existing growth needs cleaning, and any underlying water ingress needs fixing separately.
Call 051 850722 for a ventilation assessment. We’ll find the cause before we specify the cure.
