Signal Booster or DAS: Which Does Your Building Need, and What Will It Cost?

If mobile signal dies at your front door, you have two realistic ways to fix it: a licence-exempt smart signal booster, or a distributed antenna system (DAS). They solve the same problem at very different scales and prices, and much of the advice online comes from companies with a product to sell. Seneca supplies and installs both — Nextivity boosters through our shop and engineered DAS as a service — so this guide compares them honestly: what each one is, which building sizes and user mixes each suits, what UK law allows, and what the numbers actually look like.

What a signal booster actually is (and what a DAS is)

A smart signal booster — Cel-Fi, made by Nextivity, is the best-known family — takes the mobile signal that exists outside your building, amplifies it intelligently, and rebroadcasts it inside. One donor antenna outside, one or more coverage units inside, no involvement from the mobile operator required. Repeaters come in single-operator units and multi-operator systems, and support both 4G/LTE and 5G — so the real question is not what the technology can do, but how many networks your building needs covered and at what scale. One thing a repeater never does is add capacity: it redistributes the operator’s existing cell indoors, so capacity and performance are whatever that cell can give.

A distributed antenna system (DAS) is about more than coverage: it is engineered for capacity and guaranteed performance. A designed network of antennas on dedicated cabling delivers specified signal levels in every area, with the capacity planned for your device count — so it is the answer when a building needs every UK mobile network working everywhere, high user or device density handled without degradation, and performance you can measure at acceptance and hold the system to. The engineering itself is well understood — at scale the cost gap between a large multi-operator repeater project and a DAS narrows — and the biggest practical difference is the operator coordination. The real difference is the operators: taking signal from their own equipment brings agreements, coordination (increasingly via the industry’s JOTS neutral-host framework) and their timescales — which is why a typical full DAS project runs around nine months or more end to end, where repeater-based systems go in over days to weeks. It is the right spend for large warehouses, hospitals, multi-tenant offices and basements. Between a single repeater and a full active DAS sits hybrid kit like the Nextivity QUATRA series: multi-operator, distributed over structured cabling, installed in days rather than months.

So the honest framing is not booster versus DAS as rivals. It is a scale: single-operator booster, multi-operator hybrid DAS, full active DAS. Your building size, user count and network mix decide where you sit on it.

The deciding question: one network or all of them?

Before you think about floor area, answer this: whose phones need to work? A company-issued fleet on one operator is the ideal booster scenario — one network, served by a single compliant repeater. A visitor-facing office, a multi-tenant building, or any site where staff use personal phones on whatever network they chose is a multi-operator problem, and a single-network booster will generate complaints from everyone it doesn’t cover.

Building size is the second filter. A single smart booster covers a defined area around each coverage unit; you can add units, but beyond a certain floorplate — multiple floors, dense internal walls, metal-clad construction — you are effectively building a distributed system anyway, and doing it properly with QUATRA or a designed DAS is cleaner and performs better. As a rule of thumb from our own installs: a small single-floor office is comfortably booster territory if one network suffices; the same building needing every UK network is a QUATRA job; and once you are into tens of thousands of square feet or public-access venues, you are specifying a DAS with a proper design survey behind it.

There is a third filter people forget: donor signal. A booster amplifies what is outside. If outdoor signal is genuinely poor on the network you need, there is little to amplify, and a survey should confirm the donor signal before anyone spends money — which is exactly why we measure first.

Is any of this legal? The Ofcom position in one paragraph

Compliant smart repeaters are legal to use in the UK without a licence, installed statically indoors — single-operator and multi-operator versions, 4G and 5G — because they are engineered to protect the operators’ networks; the Nextivity/Cel-Fi range is designed to meet Ofcom’s requirements. What is illegal is the cheap wideband amplifier sold on marketplace sites: those interfere with the mobile networks, and Ofcom can and does act on interference. Larger multi-operator and DAS-grade installations are delivered with the appropriate operator arrangements as part of the project.

What it costs: real numbers, not ‘request a quote’

Few UK providers publish installed pricing for these systems, so here are ours. Booster hardware is off-the-shelf: our current Nextivity pricing at https://shop.senecaenterprise.com runs from £639.60 inc VAT for the ROAM R41, £794.40 for the CONNECT C41, and £1,123.20 for the GO G41. For a small single-network site the hardware is the main cost; a professional survey and installation makes sure it is the right unit, pointed at the right donor signal.

For installed systems, the pricing that matters is per square metre. Covering every network on the same floorplate costs meaningfully more than covering one — that spread is the most useful single fact in this decision, and it is why the one-network-or-all question comes first.

On ‘DAS cost per square metre’: we would treat any published per-m² rate for a full carrier-grade DAS with caution, because the honest answer is that cost is driven more by building construction, cabling routes, operator mix and signal source than by raw floor area — two buildings of identical size can be quoted very differently. For a large venue requiring full active DAS, costs are project-specific and start well above the hybrid figures here — that is a design-and-quote conversation, not a price list.

For engineered multi-operator coverage at scale, the honest way to think about price is per square metre: around £3–£7 per m² for legal, good-quality repeater systems (installed, ex VAT, modelled from our current price book for buildings from roughly 5,000 m²; fewer networks and larger buildings sit at the lower end). A 10,000 m² warehouse therefore lands around £30,000 for two-operator coverage, with more networks pushing towards £51,000. Below that size, fixed costs dominate and projects are priced individually.

And because size and monthly cost decide most budgets: on indicative 60-month finance (8% flat, subject to status), a £30,000 two-operator warehouse system is around £540 a month, and a £51,000 all-networks system around £918 a month. Ask for a finance quote alongside any system quote.

The decision checklist

Work through these five questions and the answer usually falls out on its own.

• Whose phones must work? One operator (company fleet) points to a booster; personal phones, visitors or tenants point to QUATRA or DAS.
• How big and how built? Single floor, modest area: booster. Multiple floors, metal cladding, foil-backed insulation or deep floorplates: distributed system.
• What is the outdoor signal like? Weak donor signal undermines a booster; a survey should measure this before you buy anything.
• What is the budget reality? Hardware from £639.60; engineered repeater coverage around £3–£7 per m² installed from roughly 5,000 m²; smaller buildings priced per project.
• Is this safety-critical? If lone workers, alarms or emergency calls depend on it, specify the system from a measured survey, not a guess.

How Seneca helps — and the next step

We are one of the few UK companies on both sides of this decision: we sell Ofcom-compliant Nextivity boosters off the shelf, and we survey, design and install QUATRA and DAS systems as an engineering service. That means we have no incentive to upsell you a distributed system your building doesn’t need — a £794.40 booster that solves the problem is a better outcome for everyone than an oversized install.

If you already know a single-network booster fits, buy directly at https://shop.senecaenterprise.com. If your building is larger, your users are on mixed networks, or you want the coverage measured before you commit, request a quote at https://senecaenterprise.com/get-a-quote/ and we will start with a signal survey. For the wider picture on why buildings kill mobile signal and every fix available, see our full in-building coverage guide: https://senecaenterprise.com/in-building-mobile-coverage/.

Frequently asked questions

What is a distributed antenna system (DAS)?

A DAS is a network of antennas installed through a building on dedicated cabling, fed from a central signal source, so mobile coverage is delivered evenly across the whole floorplate rather than radiating from one point. Full active DAS uses operator-grade signal sources and covers all networks; hybrid systems like Nextivity QUATRA deliver multi-operator coverage DAS-style but install far faster and without operator base-station equipment.

Signal booster vs DAS — which do we need for an office building?

Two questions decide it: whose phones must work, and how much capacity you need. If everyone is on one network and usage is ordinary, a licence-exempt smart booster is the simple, cheaper fix; mixed networks point to a multi-operator system such as a Cel-Fi QUATRA. But remember a repeater shares the capacity and performance of the operator’s cell — for high device counts or guaranteed performance, an engineered DAS with its own signal sources is the answer.

How much does a DAS system cost in the UK?

Think in two brackets. Offices and smaller buildings are priced per project, because survey, design and head-end costs are fixed. At warehouse scale, engineered repeater coverage runs around £3–£7 per m² installed, ex VAT. A full operator-fed carrier-grade DAS starts around £50,000 and is not necessarily far dearer on hardware — the difference is the operator coordination, which is why those projects typically run nine months or more. On indicative 60-month finance, a £30,000 system is roughly £540 a month and a £50,000 system roughly £900 a month.

How much does a DAS cost per square metre?

At warehouse scale, as a guide: around £3–£7 per m² installed, ex VAT, for legal, good-quality repeater systems — fewer networks and bigger buildings at the lower end of the range. Below roughly 5,000 m², fixed costs (survey, design, head-end) dominate and per-m² rates mislead, so smaller buildings are priced per project. On indicative 60-month finance, a £30,000 system is roughly £540 a month and a £50,000 system roughly £900 a month.

Repeater vs DAS — is a booster always cheaper?

Keep it simple: booster hardware starts at £639.60; engineered repeater coverage runs around £3–£7 per square metre installed (ex VAT); a carrier-grade DAS starts around £50,000. For the same building needing one network only, a booster is always the cheaper buy; the premium for covering every network is the top of the £3–£7/m² band at warehouse scale, with smaller buildings priced per project. On 60-month finance a £30,000 system is roughly £540 a month.

Are signal boosters legal in the UK?

Yes, when they are compliant. Smart repeaters meeting Ofcom’s requirements — available single- or multi-operator, 4G and 5G in the bands the exemption covers, like the Nextivity/Cel-Fi range — are legal to use indoors without a licence to use. Non-compliant wideband boosters, common on marketplace sites, are illegal in the UK.

Know it’s a one-network fix? Buy a compliant booster at shop.senecaenterprise.com. Mixed networks or a bigger building? Get a surveyed DAS quote at senecaenterprise.com/get-a-quote/.