Cooling upgrade
Planning cooling: controls, condensation & cost
Adding cooling well is mostly about getting three things right: managing condensation, setting up the controls, and budgeting realistically. Here is what to plan for.
Condensation and dew point
Cooling chills water, and chilled surfaces can fall below the dew point — the temperature at which moisture in the air condenses. Get this wrong and you get damp pipework, wet floors and, over time, mould.
A properly designed system avoids it in two ways: it never lets the cooling flow temperature drop too low for the room conditions, and it collects any condensation that does form at the fan coils, in trays plumbed to a drain. Condensation management is an engineering task, not an afterthought.
Controls and zoning
Vaillant’s system controls (such as sensoCOMFORT) include dew-point monitoring — they compare the target cooling flow temperature against the current dew point and hold it safely above. They also schedule cooling and can take an external cooling-demand signal.
On larger or mixed systems, Vaillant zoning modules let cooling be directed to some rooms and kept out of others. The right control setup is part of the design — confirm it with your installer rather than assuming default settings will suit your home.
The realistic cost
The cooling resistor itself is inexpensive. The cost of a cooling upgrade is in the system around it. The layers to budget for:
- Cooling resistor
- The coding plug that authorises cooling — £47.50.
- Fan coil units
- Typically several hundred pounds to ~£1,500+ per room unit, depending on size and type (indicative).
- Pipework, valves & drains
- New cooling-branch pipe runs, isolation valves and condensate drainage.
- Controls
- Vaillant system control and zoning modules where the system needs them.
- Installation & commissioning
- Design, fitting, balancing and commissioning by a competent installer.
These are indicative pointers, not a quote. The whole-project cost depends on the number of rooms, pipe routes, drainage and controls — a Vaillant-approved installer can price it for your home.
Use a Vaillant-approved installer
Cooling touches the electrical, refrigerant and hydronic sides of an appliance, and the condensation risk is real. Having the resistor fitted and cooling designed and commissioned by a Vaillant-approved installer keeps the work within warranty terms and makes sure the system is safe and comfortable.
Start with the genuine Vaillant cooling resistor — £47.50.