Grundfos SCALA2 Review: Cost, Install & Is It Worth It?
Whether you're dealing with a trickling upstairs shower or planning a multi-bathroom renovation, the Grundfos SCALA2 is the UK's go-to whole-house pressure booster. But it's a serious investment, so this guide covers what it actually does, what it costs to buy and install, whether you'll need a break tank, and a full step-by-step installation walkthrough — so you can decide if it's right for your home.
What Is the SCALA2 Used For?
The SCALA2 is a fully integrated, self-priming whole-house pressure booster. It packs the pump, motor, tank, sensor and non-return valve into one compact unit that adjusts automatically to demand:
- Constant pressure: Holds steady shower pressure even when someone opens a kitchen tap.
- Boosts weak mains: Lifts a feeble supply to a strong, usable pressure.
- Multi-storey: Designed for up to 3 floors and around 8 taps.
- Very quiet: Water-cooled, so around 44 dB(A) — about as quiet as a dishwasher.
First: Confirm Your Pressure Is Actually Low
Before spending £450+, check the problem is genuinely low mains pressure and not a blockage or a partly closed stopcock. Fit a mains pressure gauge and take a reading — if you're consistently below about 1 bar and your supplier isn't at fault, a booster like the SCALA2 is the right fix. If pressure is fine but flow is weak, check a flow measuring jug reading first; the cause may be a blockage a pump won't solve.
Is the SCALA2 Worth It?
For homes with genuinely low or fluctuating mains pressure affecting the whole house, the SCALA2 is one of the most effective and quietest fixes available. Its intelligent control holds constant pressure across multiple outlets and floors, and the water-cooled motor keeps noise down to dishwasher levels.
Where it's not the best value: if only one shower is weak, a smaller single-outlet shower pump may do the job for far less. The SCALA2 earns its price when the problem is system-wide.
SCALA2 Cost (UK)
| Item | Typical Cost |
|---|---|
| SCALA2 unit | £450 – £520 |
| Professional installation | £200 – £400+ (varies with pipework) |
| Break tank (if required) | Extra — depends on supply & regs |
Running costs are low — the permanent-magnet motor only runs when water is drawn and adjusts speed to demand.
How to Install the SCALA2: Step by Step
The SCALA2 is designed for "plug & pump" installation, with most electronics pre-configured. To keep your UK warranty valid, follow these steps — and use a qualified plumber for the mains connection.
🛠️ Tools & Parts Required
- ✅ Adjustable wrench
- ✅ Pipe cutter (copper or plastic)
- ✅ 2x full-bore isolation valves
- ✅ PTFE thread tape
- ✅ 1.7L water (for priming)
- ✅ Flexible braided hoses (optional)
Placement & Vibration Control
Place the pump on a solid, level surface like a concrete floor or sturdy wooden base. It's water-cooled so needs no noisy fan, but does need a little air around it.
Expert tip: Make sure the pump doesn't touch cupboard walls — even a tiny gap stops "vibration hum" echoing through the house.
Inlet & Outlet Pipes
The SCALA2 has 1-inch adjustable inlets/outlets. Use flexible braided hoses to connect to your 15mm or 22mm copper pipes — easier to fit and quieter.
Don't forget: Fit a full-bore isolation valve on both sides so you can service the pump without turning off water to the whole house.
Filling with Water
Never turn the pump on while it's dry — this burns out the internal seals. Prime it first:
- Unscrew the large priming plug on top.
- Slowly pour in 1.7 to 2 litres of clean water until it overflows.
- Hand-tighten the plug back on.
Turning It On
Plug into a standard 3-pin socket. It defaults to 3.0 bar. If your upstairs shower still feels weak, press the (+) button to increase pressure. Most UK homes settle at 3.0–3.5 bar.
Where to Buy the SCALA2 in the UK
Pricing typically runs £450–£520. Buy from established trade merchants for full warranty support.
| Retailer | Stock Status | Benefit | Link |
|---|---|---|---|
| City Plumbing | In Stock | Trade expertise & advice | View Price |
| Screwfix | Available | Next-day click & collect | Check Stock |
Frequently Asked Questions
Is the Grundfos SCALA2 worth it?
For homes with genuinely low or fluctuating mains pressure across the whole house, yes — it holds constant pressure over multiple taps and up to three floors and is very quiet. It's less cost-effective if only one shower is weak. Confirm your pressure is low with a gauge first.
How much does a SCALA2 cost?
The unit is typically £450–£520, plus a few hundred pounds for fitting depending on pipework and whether a break tank is needed.
Do I need a break tank with a SCALA2?
Possibly. UK regs generally cap direct mains draw at 12 litres/min. If the pump needs more than your supply allows, it must be fed from a break tank rather than straight off the mains. Your installer will confirm.
How many floors and taps can it supply?
Up to 3 floors and around 8 taps, holding steady pressure even with several outlets running at once.
Is the SCALA2 noisy?
No — being water-cooled, it's one of the quietest boosters at around 44 dB(A), roughly a modern dishwasher. Keeping it off cupboard walls keeps it quieter still.
Can I install a SCALA2 myself?
It's plug-and-pump, but the mains connection, water-regs compliance and any break tank are best left to a qualified plumber to keep the warranty valid. Always prime it before first use — running it dry ruins the seals.