Slow office Wi-Fi usually comes down to one of five things: the broadband line, poor access point placement, too many devices, interference, or the network not being designed for calls and cloud apps. Start by testing the wired connection, then check the wireless setup. If the cable is fast but Wi-Fi is poor, the problem is inside the office, not with the broadband provider.
That sounds obvious, but it is where a lot of time gets wasted. Teams drops out, someone blames Microsoft 365, someone else blames the laptop, and the router has been sitting behind a filing cabinet next to a microwave since 2018.
Start with the line, not the Wi-Fi
Ofcom puts it plainly: a Wi-Fi connection will not outperform the broadband service underneath it.[1] Run a speed test from a device plugged directly into the router or firewall with an Ethernet cable. Do it during a quiet period and again when the office is busy.
If the wired test is poor, look at the internet service, router, firewall, cabling, or provider issue first. If the wired test is good but wireless users still struggle, the Wi-Fi design needs attention.
For businesses, upload speed matters more than people think. Cloud backups, Teams calls, SharePoint sync, hosted apps and VoIP can all suffer when the upload is saturated. A connection can look fine for browsing and still be awful for calls.
Check where the access points actually are
Router and access point placement matters. Ofcom says Wi-Fi signals weaken as they pass through objects, and materials such as water, metal and glass can block the signal.[1] That is bad news for access points hidden in cupboards, server cabinets, kitchens, stockrooms or behind reception desks.
A decent office Wi-Fi setup should place access points where people work, not where the broadband line happens to enter the building. Ceiling mounted access points usually beat a single router on a shelf, especially across meeting rooms, thick walls, workshops, warehouses or care settings.
If staff say, “it works near the router but not in the back office”, that is not a mystery. It is a coverage problem.
Count the devices, including the quiet ones
Wi-Fi slows down when too many devices compete for the same airtime. Ofcom notes that newer routers can handle more connected devices before performance noticeably drops.[1]
Do not count only laptops. Add mobiles, tablets, card machines, printers, door entry, CCTV, smart TVs, barcode scanners, guest devices and any IoT kit someone plugged in years ago. Many of those devices are quiet most of the day, then suddenly noisy when updates, sync jobs or cloud uploads kick in.
A business network should usually separate staff, guest and device traffic. Guest Wi-Fi should not be able to see the till, printer, NAS, server, CCTV recorder or admin devices. That is partly performance, partly basic hygiene.
Treat Teams calls as a network test
Microsoft says Teams can suffer when there is insufficient bandwidth, firewall or proxy blocking, jitter, packet loss, or poor Wi-Fi design.[2] It also says Teams can deliver HD video quality in under 1.5 Mbps, but actual usage changes with layout, video resolution and frame rate.[2]
That means a single call does not need a huge connection. Ten people on calls at the same time is different. Ten people on calls while OneDrive syncs, Windows updates run and someone uploads a design file is different again.
If Teams calls are the main complaint, check:
- whether users are on 2.4 GHz or 5 GHz;
- whether access points overlap on the same channels;
- whether Quality of Service or Wi-Fi Multimedia is enabled;
- whether Teams traffic is being dragged through a VPN;
- whether the firewall is allowing the right Microsoft 365 traffic.
Microsoft specifically recommends planning Wi-Fi bands and access point placement for real time media, and it notes that 5 GHz is better suited to real time media but needs enough access points for coverage.[2]
Do the boring security checks too
Performance problems and security problems often share the same root cause: old kit that nobody owns. The NCSC’s small organisations guide says there are 5.5 million small organisations in the UK with 0 to 49 employees, and that one in two small businesses suffer a cyber incident every year.[3]
That does not mean your slow Wi-Fi is a breach. It does mean the same review should check firmware updates, admin passwords, unsupported routers, guest isolation and who can change the network settings.
If the router password is still the one printed on the card, fix that. If staff and guests share the same Wi-Fi password, fix that too. If nobody knows when the firewall or access points were last updated, that is the answer.
A quick checklist before you replace anything
Before buying new broadband or another booster, work through this:
- Test the wired speed at the router or firewall.
- Test Wi-Fi speed in each work area.
- Note where calls drop, not just where the signal icon looks weak.
- Count business devices, guest devices and hidden devices.
- Check whether users are on 2.4 GHz, 5 GHz or 6 GHz.
- Look for interference from kitchens, cordless phones, screens, metal racking and thick walls.
- Check router, firewall and access point firmware.
- Review guest Wi-Fi separation.
- Check Teams call quality reports if Microsoft 365 is in use.
- Replace extenders with proper access points or mesh only when the survey supports it.
Boosters can help at home, but they are a poor fix for many offices. If the business depends on cloud systems, VoIP, card payments or video calls, treat Wi-Fi as infrastructure rather than a convenience.
When to speak to BMT
Speak to BMT if Wi-Fi problems are affecting calls, payments, cloud apps or customer service. We can check whether the issue is the broadband line, the internal network, wireless coverage, Microsoft 365 call quality, or old hardware that needs replacing.
The fix is not always expensive. Sometimes it is moving access points, splitting guest traffic, replacing an ageing router, or stopping everything from fighting on the same channel. The point is to test before spending.
Sources
[1] https://www.ofcom.org.uk/phones-and-broadband/coverage-and-speeds/improving-your-wifi-experience — Improving your wifi experience – Ofcom
[2] https://learn.microsoft.com/en-us/microsoftteams/prepare-network — Prepare your organization network for Microsoft Teams
[3] https://www.ncsc.gov.uk/collection/small-organisations-guide-to-cyber-security — Small organisations guide to cyber security – NCSC