In depth
The cost of adding cooling to a heat pump
The realistic cost layers — from the plug to a full cooling circuit
Adding active cooling to a Vaillant heat pump has several cost layers. The cooling plug is the smallest of them — tens of pounds on eBay for the bagged 0020266328. The larger costs are the cooling-capable emitters, controls, drainage and installation. This page sets out the realistic layers so you can plan. All figures here are indicative ranges, not quotes — your actual cost depends on how many rooms you want cooled and your site.
Updated
Buy the Vaillant cooling plug on eBay
Same blue plug, two packs. Choose the boxed 0020269259, or get the identical 0020266328 for a fraction of the price.
Original Vaillant box, labelled “Coding plug, cooling function”
Buy on eBaySold by eBay seller boarder895 · 100% positive feedback · 600+ feedback · on eBay since 2003 · 20+ plugs sold
The plug is the small part of the bill
The Vaillant cooling plug costs tens of pounds on eBay as 0020266328. The boxed 0020269259 — the same plug, labelled “Coding plug, cooling function” — costs several times as much. Either way it is a small, fixed cost, and it is what authorises cooling.
Everything else is the system that actually delivers cooling. Those costs are larger and more variable, because they depend on your home rather than on a single component. It helps to think of the project in layers.
The cost layers explained
A cooling upgrade is usually made up of five layers: the cooling plug, the cooling-capable emitters, the controls, the drainage and pipework, and the installation labour. The table below sets out indicative ranges for each.
The emitter layer is normally the biggest. Hydronic fan coil units typically cost from several hundred pounds to £1,500 or more per room unit before installation, depending on size and type. Multiply that by the number of rooms you want cooled and the emitter layer alone can be substantial.
Why the total varies so much
There is no single price for "adding cooling" because two homes are rarely alike. The main variables are the number of rooms to be cooled, how easy it is to route the extra pipework and condensate drains, whether new controls or zoning modules are needed, and how much making-good and boxing-in the job involves.
A single-room cooling upgrade is a much smaller project than cooling a whole house. The only reliable figure is a written quote from a Vaillant-approved installer who has surveyed your property.
Treat figures as indicative, not quotes
The cost bands on this page are indicative ranges drawn from publicly visible component pricing. They are there to help you set expectations, not to price your job.
Component prices also move over time and vary by supplier and specification. Use the ranges to understand the shape of the cost — a small fixed cost for the plug, a larger variable cost for the system — and get a proper quote for the actual numbers.
Indicative cost layers for an active-cooling upgrade. These are typical ranges to aid planning — not quotes. Whole-project cost depends on room count and site.
| Cost layer | What it covers | Indicative cost |
|---|---|---|
| Cooling plug | Vaillant 0020266328, or the identical boxed 0020269259 | Tens of pounds on eBay; the boxed version costs several times more |
| Cooling emitters | Hydronic fan coil units, one or more per room cooled | Several hundred pounds to £1,500+ per room unit (indicative) |
| Controls | Vaillant system control such as sensoCOMFORT, plus zoning modules where needed | Varies with system — quote required |
| Drainage and pipework | Condensate trays and trapped drains, extra pipe runs, insulation | Site-dependent — quote required |
| Installation | Survey, fitting, commissioning and making-good | Site-dependent — quote required |
Frequently asked questions
How much does it cost to add cooling overall?
There is no single figure. The cooling plug is tens of pounds on eBay; the wider upgrade depends on how many rooms you cool and your site. Indicative emitter costs alone run from several hundred pounds to £1,500 or more per room unit before installation. Get a written quote for your home.
Are the figures on this page quotes?
No. They are indicative ranges to help you plan. Actual prices vary by supplier, specification, room count and the difficulty of the installation. Only a surveyed quote is reliable.
What is the cheapest way to add cooling?
Cooling fewer rooms costs less, because the emitter layer scales with the number of room units. On the plug itself, the bagged 0020266328 is the same plug as the boxed 0020269259 for a fraction of the price.
Can I budget for just the plug?
Only if your heat pump already has cooling-capable emitters, drainage and controls in place. For most homes the plug is one line on a larger bill, because the system also has to be able to deliver cooling.
What about running costs?
This page covers the cost of installing cooling, not running it. Active cooling uses the compressor, so it draws electricity when in use, though a heat pump remains an efficient way to move heat.
Related guides
Ready to buy? Both plugs are on eBay
The plug inside is the same — choose the pack. 0020266328 is the best value; 0020269259 comes boxed and labelled “Coding plug, cooling function”.
Original Vaillant box, labelled “Coding plug, cooling function”
Buy on eBaySold by eBay seller boarder895 · 100% positive feedback · 600+ feedback · on eBay since 2003 · 20+ plugs sold
provenance: sha256:e50a78fdc755c096… · machine-readable: claims.json · llms.txt