How to choose the right size
Combi “size” usually refers to domestic hot water power (kW), which affects hot-water flow at taps and showers. Heating output is modulating and is balanced during commissioning. A larger kW model generally delivers higher hot-water performance, useful for higher demand.
Find your size (quick tool)
Answer a few questions and we’ll suggest 25kW or 30kW.
Quick comparison: Main Eco Compact 25kW vs 30kW
| Feature | Eco Compact 25kW | Eco Compact 30kW |
|---|---|---|
| Best for | 1 bathroom, modest hot-water demand | Higher hot-water demand / faster delivery |
| Form factor | Compact cupboard-friendly design (installer must maintain service clearances) | |
| Hot-water performance | Solid for single shower/tap usage | Stronger for busy periods and higher flow |
| Efficiency | Modern condensing efficiency when correctly set up and serviced | |
| Controls | Compatible with a range of modern controls (installer to confirm specifics) | |
| Typical use cases | Flats, small homes, light usage | Family homes wanting quicker hot water |
| Link | Buy 25kW | Buy 30kW |
What people like about Eco Compact
- Compact footprint – tidy cupboard installs with proper clearances.
- Modern condensing efficiency when commissioned correctly.
- Choice of 25kW or 30kW for different hot-water needs.
- Works with a variety of modern heating controls (installer to confirm).
Things to consider
- Combi boilers heat water on demand; simultaneous showers reduce flow.
- Sizing should be done by a qualified Gas Safe installer.
- Annual servicing is required to maintain performance and warranty.
Frequently asked questions
Is 30kW always “better” than 25kW?
No — it depends on hot-water demand and mains pressure/flow. Bigger kW can deliver faster hot water, but correct sizing avoids overspecifying.
Will it fit inside a kitchen cupboard?
Eco Compact is designed for tight spaces. Your installer must follow the manufacturer’s fitting/clearance rules and ensure ventilation/service access.
Do I need new controls and a new flue?
Often recommended during a new install, but compatibility varies. Your installer will advise on approved flues, accessories and controls.
What about warranty?
Warranty length and terms depend on pack, registration and servicing. Keep your Benchmark logbook and receipts. Ask us for current offers before buying.
Ready to order or still unsure?
We’re happy to help you compare, check compatibility and arrange delivery or collection from our Reading trade counter.
Buy Eco Compact 25kW Buy Eco Compact 30kW
Prefer to talk? Call 0118 958 8882 or use live chat on getplumb.co.uk.