Five Apartments, Three WiFi Generations, Zero Lab Conditions: What Concrete Walls Actually Do to Your Router

Every router box you've ever picked up at Best Buy has a number on it. A big, bold, impossibly optimistic number. WiFi 6: up to 9.6 Gbps. WiFi 6E: same claim, different band. WiFi 7: up to 46 Gbps if you believe the marketing copy. These figures are generated in anechoic chambers by engineers who have never, apparently, met a 1940s Manhattan apartment building.

We have.

Over the course of three weeks, our team dragged a standardized test kit — including routers representing each of the three current WiFi generations — into five distinct US apartment types. We ran identical throughput tests at the same distances, logged signal degradation, and compared what we measured against what the box promised. The results were, to put it charitably, humbling for the router industry.

The Five Battlegrounds

We didn't cherry-pick easy scenarios. Here's what we tested in:

Pre-War Walk-Up, Brooklyn, NY — Built in 1927. Plaster-over-brick walls, original cast-iron radiator pipes running through the interior, and roughly 14 inches of combined wall material between rooms. The kind of place where your signal goes to die.

Modern High-Rise, Chicago, IL — Post-2010 construction with poured concrete slabs between floors and metal-studded drywall partitions. Looks sleek, performs like a Faraday cage.

Basement Unit, Philadelphia, PA — Half the unit sits below grade. Concrete foundation walls on two sides, shared laundry room with commercial appliances next door, and a drop ceiling with metal framing throughout.

Corner Unit, Austin, TX — Mid-rise from the early 2000s. Two exterior walls, which sounds like a win until you realize one faces a parking garage full of interference sources. The layout also forces the router into a dead-center hallway position to reach all rooms.

Mid-Floor Unit, Seattle, WA — The most "average" scenario we could find. Standard drywall construction, neighbors above and below, moderate channel congestion from surrounding units.

The Test Setup

For each location, we placed the router in the spot a normal person would actually put it — near the modem, which is rarely in a geometrically ideal position. We then ran iPerf3 throughput tests from three distances: 10 feet (same room), 30 feet (one wall), and 60 feet (two walls or equivalent obstruction). Every test was repeated five times per distance, per router, and we averaged the results. We also logged signal strength in dBm and noted channel congestion using a WiFi analyzer.

The routers: a mid-range WiFi 6 unit, a WiFi 6E router at a similar price tier, and a current-generation WiFi 7 router. We're not naming specific models here because this is about generational behavior, not brand wars.

What the Numbers Actually Showed

Same Room: All Three Perform Well (With One Catch)

At 10 feet with line of sight, all three generations delivered strong throughput. WiFi 7 edged ahead in the modern high-rise and the Austin corner unit, where 6 GHz and the new 320 MHz channel width had room to breathe. WiFi 6E was close behind. WiFi 6 held its own on 5 GHz.

The catch? In the pre-war Brooklyn apartment, even at 10 feet, the 6 GHz band on both 6E and 7 routers took a hit. Higher frequencies attenuate faster through dense materials — and plaster-over-brick is about as dense as residential construction gets. The 6 GHz band lost nearly 30% more throughput than 5 GHz at the same distance in that building.

One Wall: The Gap Opens Up

This is where things got genuinely interesting. Pushing through a single wall — whether it's 1920s plaster or modern drywall — revealed a consistent pattern across all five locations: WiFi 7's 6 GHz performance degraded faster than WiFi 6's 5 GHz performance, but WiFi 7's multi-link operation (MLO) partially compensated by simultaneously using 5 GHz.

In practical terms, a standalone WiFi 6E router without MLO took the worst beating at this range. Its only high-performance band is 6 GHz, and that band genuinely struggles with wall penetration. We saw throughput drops of 40–55% from the same-room baseline in four out of five locations.

WiFi 6, running on 5 GHz, dropped 25–35% through the same walls. Less glamorous technology, more forgiving physics.

WiFi 7, thanks to MLO dynamically blending bands, landed somewhere in between — closer to WiFi 6's real-world resilience while still pulling higher peak numbers when conditions allowed.

Two Walls or 60 Feet: Where Generations Diverge Sharply

The pre-war Brooklyn apartment was the most punishing. At 60 feet through two plaster-brick walls, the WiFi 6E router delivered speeds that were, frankly, embarrassing relative to its price tag — we clocked throughput degradation of nearly 70% from the rated baseline. The 6 GHz band was essentially unusable; the router fell back to 2.4 GHz for most of the connection.

WiFi 6 dropped around 50% at this range in the same building — not great, but functional. You'd stream Netflix without crying.

WiFi 7 managed the best result here, primarily because MLO kept 5 GHz active as a fallback while opportunistically using 6 GHz when signal conditions briefly improved. Even so, we're talking 45–55% degradation from spec in the worst buildings. The basement Philadelphia unit was similarly brutal, with concrete foundation walls adding another variable that hurt all three generations roughly equally.

The Seattle mid-floor unit — the closest to a "normal" apartment — gave the most optimistic results. WiFi 7 genuinely pulled ahead here, and the premium over WiFi 6 started to feel justifiable.

The Part Nobody Puts on the Box

Here's what we kept coming back to throughout this whole test: the generational leap matters a lot less than your building's construction date.

If you live in a pre-war building, a basement unit, or anywhere with poured concrete walls, you are fighting physics that no router generation can fully overcome. Spending up for WiFi 7 will get you better performance than WiFi 6E in those environments — primarily because MLO gives it a smarter fallback strategy — but you will not come close to spec. Not even close.

If you're in a modern, standard drywall construction apartment, WiFi 7 starts to make a real case for itself, especially if you have high-bandwidth devices concentrated in a few rooms. WiFi 6 still performs respectably, though.

WiFi 6E occupies an awkward middle ground. Its sole premium feature — the 6 GHz band — is also its biggest liability in real-world residential environments. Unless your apartment is basically one open room, you're paying for capability that your walls will frequently take away from you.

What We'd Actually Recommend

Old building, lots of walls: WiFi 7 if budget allows (MLO helps), but don't rule out a mesh system over a single powerful router. Spreading nodes around beats throwing more GHz at the problem.

Modern construction, standard layout: WiFi 7 is worth the upgrade if you're buying new. WiFi 6 is still perfectly solid if you already own one.

Basement or below-grade unit: Honestly? Powerline adapters and a secondary access point might serve you better than any router upgrade. We said what we said.

The shootout lesson here is the same one we keep learning: real apartments don't care about theoretical maximums. Buy for your walls, not for the box.