You bought the house and inherited the wiring. Maybe it’s a 1995 rambler in Bountiful with a single phone line behind the couch. Maybe it’s a mid-2000s Daybreak home in South Jordan that was pre-wired for cable TV and nothing else. Now the basement home office needs a wired network drop, the upstairs Apple TV stutters on Wi-Fi, and pulling new Cat6 through finished walls quotes at four grand.
This is the retrofit problem. You don’t need a whole-house rewire; you need one or two solid wired links between rooms. The three options on the table are MoCA (Ethernet over coax), powerline (Ethernet over AC wiring), and actually pulling Ethernet. Here’s what each one really does, when each one works, and why one of them quietly wins almost every retrofit we take on.
The short answer
- Ethernet is always the best answer when you can get it. Nothing beats a properly terminated Cat6 run.
- MoCA (over the coax the builder already ran) is the surprisingly-good runner-up and our default recommendation when pulling cable would be invasive or cost-prohibitive.
- Powerline is the last resort. It works sometimes, in some houses, in some outlets, and it’s the retrofit option we least enjoy defending at the end of a support call.
Ethernet: still the gold standard
A proper Ethernet run gives you full gigabit (or 2.5 Gbps / 10 Gbps with the right cable and hardware), low latency, zero contention, and Power over Ethernet support for cameras and access points. It’s not a close race — it’s the reference standard that everything else is compared against.
The reason we’re even having the MoCA vs powerline conversation is that pulling new Ethernet through finished walls can be disruptive. If the room you need to reach is above an unfinished basement with accessible joist bays, or the wall has a direct line to the attic, we’ll almost always just pull the cable — it’s usually cheaper than the homeowner assumes and it’s the only option that permanently fixes the problem. We covered why the cable category itself matters in the Cat5e vs Cat6 vs Cat6A post.
When cable pulls are genuinely not feasible — finished basement ceilings with no access, two-story homes with no attic drop, rented or historic properties — that’s when the retrofit options earn their place.
MoCA: the retrofit sleeper hit
MoCA stands for Multimedia over Coax Alliance. It runs full-duplex Ethernet over the same RG-6 coax cable the builder probably ran to every TV location in your house during construction. If you can see a coax jack on the wall, you probably already have a MoCA-ready path to wherever the cable enters the house.
Modern MoCA 2.5 adapters deliver roughly 1 Gbps sustained in each direction with single-digit millisecond latency. MoCA 3.0 pushes that to 2.5 Gbps. In practice, a well-installed MoCA link is indistinguishable from a real Ethernet cable for streaming, video calls, gaming, and everyday file transfers.
How it works in a typical install:
- One MoCA adapter at the network rack or router, connected by coax to the house’s cable plant.
- A second MoCA adapter at the far room (the one with the existing coax jack behind the TV or in the home office).
- An Ethernet cable from the far adapter into a small switch or directly into the device.
- A MoCA PoE filter installed at the point-of-entry (where the ISP coax enters the house) to keep MoCA signal from leaking onto the neighborhood cable plant.
That last bullet is the one homeowners miss when they DIY this. Without the PoE filter (the name is unfortunate — it’s a point-of-entry filter, nothing to do with Power over Ethernet), your MoCA traffic can create interference for your cable modem and, in rare cases, leak onto the neighbor’s line. It’s a five-dollar part that every pro install includes.
Where MoCA shines
- Reaching a basement or upstairs room where coax already exists but Ethernet doesn’t.
- Adding a second access point location to extend Wi-Fi with a wired backhaul, which is exactly what the mesh Wi-Fi vs wired APs post is about — MoCA makes wired APs possible in a house that wasn’t wired for them.
- Feeding an office or game room in a home theater where the homeowner doesn’t want to open drywall.
Where MoCA doesn’t work
- Houses built without coax runs, or where coax was cut out during a remodel.
- Coax runs with splitters that aren’t MoCA-rated — most modern splitters (labeled 5–1675 MHz or “MoCA-compatible”) pass the signal. Older 5–900 MHz splitters block it and need replacing.
- Situations where you need PoE at the far end — MoCA carries data, not power, so cameras and access points still need a local PoE source.
Powerline: last resort, with receipts
Powerline adapters (HomePlug AV2, G.hn) claim speeds like “2000 Mbps” on the box. In practice, real-world throughput is highly dependent on the electrical wiring of your house, which breaker each outlet is on, the age of the wiring, and what else is drawing current at that moment.
The common failure modes we see when homeowners try powerline before calling us:
- Different breakers kill the link. If the two adapters are on different circuits, signal has to travel through the breaker panel and back down. Speeds drop from 900 Mbps to 40 Mbps, or the link fails entirely.
- GFCI and AFCI outlets filter the signal. Kitchens, bathrooms, and any outlet installed to 2014+ code often can’t carry powerline reliably.
- Appliances nuke it. A vacuum cleaner, microwave, or LED dimmer switch on the same circuit drops the link for 30–90 seconds at a time. Guess what’s running during a Zoom call.
- Surge protectors filter powerline out entirely. Plug a powerline adapter into a power strip and it will read as disconnected. It has to be in the wall outlet directly.
- Older wiring is hostile. Houses with aluminum wiring or 1960s knob-and-tube runs can see sub-20 Mbps throughput no matter how expensive the adapters.
When powerline works, it’s cheap and simple. When it doesn’t, it fails unpredictably and the homeowner blames the ISP, the router, or the devices rather than the powerline link. That’s the support burden we try to steer people away from.
Throughput and latency, head to head
Numbers are from installs we’ve measured across Utah homes — not marketing specs.
- Ethernet (Cat6): 940 Mbps sustained on a gigabit link, 1–2 ms latency.
- MoCA 2.5: 700–950 Mbps sustained in each direction, 3–7 ms latency.
- Powerline (HomePlug AV2, same circuit): 150–400 Mbps, 5–15 ms latency when idle, variable spikes under load.
- Powerline (different circuits): 20–100 Mbps, 10–40 ms latency, frequent drops.
- Wi-Fi mesh with wireless backhaul (for reference): 150–400 Mbps at two hops, highly variable latency. The reason wired backhaul exists in the first place.
What this means in a real retrofit
The decision tree we walk through with homeowners who can’t easily pull new cable:
- Can we pull Ethernet? Unfinished basement ceiling, accessible attic, or a chase we can fish? Do that. The cost is almost always worth it on a 20-year timeline.
- Is there coax at both endpoints? If yes — MoCA. Two adapters, a PoE filter, maybe a splitter upgrade. Done in an afternoon, performs like real Ethernet.
- No coax either? Consider whether a single Cat6 pull to a central second-floor location is feasible — you’d typically use that to mount an access point that covers the area wirelessly. A single-drop-plus-AP combination often solves more problems than three powerline adapters.
- Powerline as last resort. If the device is low-bandwidth and latency-tolerant (smart TV, smart speaker, light usage), and the two outlets are on the same circuit, and we’ve already exhausted everything above — then powerline. With the caveat that it might fail in six months when a new appliance joins the circuit.
Utah-specific note on older homes
Older homes along the Avenues, the Marmalade, and parts of Ogden frequently have partial coax, partial knob-and-tube, and plaster walls that are brutal to fish new cable through. MoCA is often the only non-destructive option, and it usually works because the coax was run in the last upgrade wave in the late 90s or early 2000s. We’ve had MoCA installs in 1910-built houses hit 900 Mbps because the coax itself was installed in 2002 and is in excellent shape.
Newer builds in Lehi, Herriman, and Saratoga Springs are often better served by going back to first principles — if the house is under construction or still in the remodel phase, it’s worth walking through our pre-wire checklist and pulling real Cat6 before drywall goes up.
Bottom line
Ethernet if you can, MoCA if you can’t, powerline only when the other two are truly off the table. For retrofit homeowners with finished walls and existing coax, MoCA is the answer far more often than people realize — it’s the technology that lets houses built twenty years ago participate in modern Wi-Fi 6E and 10-gig-fiber networks without rebuilding the walls. Powerline is a gamble. Ethernet is the reference. And the cheapest retrofit is the one you don’t have to redo eighteen months later.
Keystone Integration handles retrofit networking across Bountiful, Salt Lake City, Ogden, and the rest of the Wasatch Front — from MoCA installs in finished homes to full Cat6 pulls in new construction. See our full service list or reach out for a site survey to figure out which retrofit option fits your home.