If you live in a Marchmont tenement, you'll know the pattern. The Wi-Fi is fine all day — fast enough for a Teams call, a 4K stream and a download all at once. Then somewhere between half-past-six and seven o'clock, the same connection that ran perfectly an hour ago starts buffering, video calls go grainy, and pages take a beat too long to load. By eleven it's usually back to normal. Nothing on your router has actually broken — what's changed is the Wi-Fi airspace around you. This is one of the most common callouts we get from Marchmont and the surrounding tenement streets, and the fix is almost always the same.
If you'd rather skip the DIY and have someone sort it on-site, our networking and Wi-Fi team covers Marchmont, Bruntsfield, Newington and the wider south side of Edinburgh.
Why It Always Hits Around 7pm
Wi-Fi doesn't have unlimited room to operate. The 2.4 GHz band most older devices still use has only three non-overlapping channels in the UK — 1, 6 and 11 — and every router in every flat around you is fighting for one of them. During the day, most of those routers are quiet because their owners are at work. From around 7pm, everyone gets home, the Smart TVs wake up, the kids' tablets connect, and suddenly the band is saturated.
Your router doesn't slow down so much as it starts having to wait its turn. Wi-Fi works on a polite "listen first, then transmit" basis, so when twenty-plus networks are all on the same channel, every device spends a growing share of its time waiting for an opening rather than actually moving data.
The Tenement Geometry That Makes Marchmont Worse
Every dense residential area has this problem, but Marchmont has a particular shape of it. The flats are stacked tightly — typically four storeys with two flats per landing — and the internal walls are mostly stone or lath-and-plaster rather than the thin stud walls of newer builds. Stone walls block 5 GHz Wi-Fi much more than 2.4 GHz, so devices that could otherwise hop onto the quieter, faster 5 GHz band often refuse to and cling to the congested 2.4 GHz band instead.
The student-let density on streets like Warrender Park Road and Marchmont Crescent compounds it. A single tenement stair might have eight separate broadband contracts, eight routers, and another twenty or so smart-home devices — bulbs, doorbells, speakers — all broadcasting in the same airspace. From a Wi-Fi survey app on a Marchmont landing, it's normal to see 25 to 40 networks visible at once.
A Real Marchmont Bench Example
A customer in a top-floor flat off Marchmont Road called us in late spring because their evening video meetings had become unusable. They'd already tried the obvious — rebooted the router, moved it onto the bookshelf, even bought a new ISP-supplied router from a different provider. Nothing helped from about half-six onwards.
When we ran a Wi-Fi scan on the landing, the picture was immediately obvious: 27 visible networks, 21 of them sitting on 2.4 GHz channel 6. Their own router had "auto channel selection" enabled — which sounds clever, but in most consumer routers only chooses a channel at boot and then sticks with it. It had picked channel 6 at 3am, when the airspace was empty, and never re-evaluated.
The fix took about fifteen minutes. We logged into the router, manually moved 2.4 GHz to channel 1 (the quieter of the three on that stair), split the 2.4 GHz and 5 GHz networks into two separate SSIDs so the laptop would prefer 5 GHz, and moved the smart bulbs and the doorbell onto the slower 2.4 GHz SSID where they belong. The 7pm slowdown vanished that evening and hasn't come back.
What Actually Fixes It (In Order)
If you want to try this yourself before calling anyone out, this is roughly the order we work through on a Marchmont callout:
- Split your 2.4 GHz and 5 GHz networks into two SSIDs. Most ISP routers merge them by default ("BT-Whatever" covers both). Splitting them lets you force your laptop, phone and TV onto 5 GHz, which is much less congested in tenements because it doesn't carry through stone walls as well — ironically, that's what saves it.
- Manually pick a 2.4 GHz channel. Install a basic Wi-Fi scanning app on a phone, see which of channels 1, 6 and 11 is the quietest on your landing, and set your router to that channel manually rather than "auto".
- Move smart-home devices to 2.4 GHz only. Bulbs, plugs, doorbells and most thermostats can't use 5 GHz anyway. Putting them on a 2.4-only SSID keeps them from clogging the band your laptop also wants to use.
- Reposition the router. Out of the bottom of the TV unit, off the floor, away from the microwave, and ideally roughly central in the flat. In a Marchmont tenement that's usually the hallway, not the living room.
When the Router Itself Is the Problem
Sometimes the standard ISP-supplied router genuinely isn't up to a tenement environment, particularly if it's three or four years old and was built for a small modern semi rather than a busy stone-walled flat. A modern Wi-Fi 6 router handles congested airspace very differently — it can talk to multiple devices at once instead of one at a time — and is often the right upgrade for a heavy-use Marchmont household.
If you do replace the router, please don't put the old one in the wheelie bin. ISP routers contain a small lithium-backed clock battery, a fair amount of recoverable copper and a board that absolutely shouldn't end up in landfill. Bring the old kit to our IT recycling and e-waste service — we strip what's usable and recycle the rest properly.
Frequently Asked Questions
The questions we hear most often from Marchmont and Bruntsfield customers when evening Wi-Fi slowdowns come up.
- Why does it always start exactly around 7pm? That's when everyone gets home from work, Smart TVs wake up for streaming, and kids' devices come online. The 2.4 GHz airspace on your landing goes from quiet to saturated in about thirty minutes.
- Will a Wi-Fi extender fix it? Usually not — extenders typically rebroadcast on the same congested channel and can actually make things worse on a tenement landing. A proper mesh kit, or a better-placed single router on 5 GHz, almost always beats an extender.
- Is 5 GHz always better in a tenement? For the device you're actually using (laptop, phone, TV box) — yes, almost always. 5 GHz doesn't travel through neighbours' stone walls, which sounds bad but actually means it stays cleaner for you.
- Do I need to change ISP? Very rarely. Nine times out of ten the line into the flat is fine and the problem is the Wi-Fi airspace inside, not the broadband connection itself. A speed test plugged into the router by cable will confirm this in two minutes.
Want Someone to Sort the Wi-Fi For You?
If you'd rather skip the channel-scanning and have somebody walk through the flat, measure the airspace properly, separate the bands and place the router where it actually wants to live, we cover Marchmont, Bruntsfield, Morningside, Newington and the wider south side with our home and office callout service. We'll bring a survey laptop, test before-and-after speeds, and only recommend new hardware if the airspace genuinely needs it. Book a callout online and we'll get the evening Wi-Fi behaving again.
Last updated: 24 June 2026