Why putting your router on the window sill ruins your Wi‑Fi and what broadband engineers advise instead

Mine used to live there too, perched on the window sill like a little lighthouse, its lights winking at passing cars. It felt tidy and obvious: cable comes in by the window, router sits by the window, job done.

Then one winter, with everyone home streaming at once, the video calls turned into pixel soup. A visiting broadband engineer glanced at the sill and winced. “You’ve basically pointed your Wi‑Fi at the street,” he said, lifting the router like a plant that had been left in the wrong corner. We moved it one metre and the house felt different. Same kit, better thought.

This isn’t about buying a new router. It’s about giving the one you already own a fighting chance.

Why the window sill quietly sabotages your Wi‑Fi

On the window sill, your Wi‑Fi is doing two awkward things at once. It’s throwing half its signal out through the glass, and it’s trying to thread what’s left through walls and radiators behind it. From the pavement, your network looks powerful. From the back bedroom, not so much.

Glass and metal window frames reflect and scatter radio waves. Double or triple glazing can bounce certain Wi‑Fi frequencies back into the room in odd directions, leaving pockets of weak signal. Curtains, blinds and even the radiator under the sill soak up more of what’s left.

Most routers send their signal out in a rough doughnut shape, not a laser beam. Put the router against an outside wall and that doughnut is half outside your home. You’re paying for coverage you can’t use.

“Think of the router as a lamp,” one Openreach engineer put it. “If you shove it in the corner by the window, expect shadows.”

The science in the signal

Wi‑Fi is just radio, and radio has habits.

Routers typically use 2.4 GHz and 5 GHz bands. These frequencies travel through air easily but lose strength when they hit dense or reflective materials.

On a window sill, they meet:

• Glass and coatings – modern low‑E glass and metallic films reflect and absorb radio waves.
• Metal frames and radiators – act like mirrors and barriers, bouncing signal unpredictably or blocking it outright.
• Street noise – passing cars, neighbouring Wi‑Fi, and outdoor devices all add interference right where your router is sitting.

Inside the house, the signal then has to fight through:

• Brick or blockwork walls
• Chimney breasts and flues
• Wardrobes full of clothes
• Big metal appliances like fridges and ovens

Put the router at the edge of the space and every obstacle hurts more. Move it nearer the centre and the same obstacles affect a smaller proportion of the coverage.

Where broadband engineers actually put routers

When engineers are left to their own devices, they almost never choose the window sill.

They quietly look for three things:

• Height – about waist to chest height, not on the floor and not squashed on a skirting board. A shelf, sideboard, or sturdy bookcase works well.
• Centrality – somewhere roughly in the middle of the area where people actually use devices, not at the very front of the house.
• Breathing room – with some clear air around it, not buried in a cupboard or pressed against a TV.

They also keep an eye on what’s nearby:

• Away from microwaves, baby monitors, cordless phones and Bluetooth speakers.
• Not directly behind the TV or soundbar, where the electronics and casing block and confuse signal.
• Not on top of a Wi‑Fi printer, smart hub, or any other box full of radios.

“If you can see it from the spots you care about most, the signal usually can too,” as one Virgin Media installer told a customer.

A simple repositioning routine, step by step

You don’t need special tools, just a bit of time and a longer cable if the existing one is tight.

1. Walk your home with your phone
   Stand where you actually use Wi‑Fi: sofa, bed, home office chair. Note where it feels weak or drops out.

2. Pick a better spot
   Aim for:

   • Roughly central in the flat or on the main floor.
   • Off the floor on a solid surface.
   • At least 20–30 cm away from big metal objects or thick walls.

3. Free the cables
   If the broadband socket or fibre ONT is by the window, ask your provider about a longer cable or, if allowed, buy a decent‑quality replacement of the same type and spec. Keep bends gentle, avoid running it under doors that slam.

4. Position the router like a small radio mast

   • Stand it upright, the way the maker intended.
     
   • If it has visible antennas, start with them vertical.
     
   • Leave a hand’s width of space around it for airflow.

5. Test and tweak
   After moving it, repeat your walk with a phone or laptop.

   • Try a speed test in the furthest room.
     
   • Open a video call or stream something and see if it holds steady.
     Move the router by 30–50 cm at a time if one room still struggles; small shifts matter.

For larger homes, one router in a good spot still may not reach everything. In that case, engineers often recommend a proper mesh system or wired access point rather than more guesswork with window sills.

Mistakes to avoid

Some habits make a good router behave badly, even in the right room.

• Hiding it in a cupboard
  Wood, doors, and coats turn the cupboard into a muffler. Neat, yes; effective, no.
• Stacking boxes on top of it
  It needs air to keep cool. Heat shortens its life and can cause slowdowns.
• Balancing it on the TV unit behind the telly
  The screen and metal frame absorb and reflect signal. It’s a common instinct, and a common issue.
• Putting extenders on window sills too
  An extender repeating a poor, edge‑of‑house signal only multiplies the problem. They work best where the main signal is still strong.

Quick placement recipes for different homes

Home layout	Better router spot	Notes
Long terrace or flat	Central hallway shelf or sideboard	Keeps both front and back rooms in reach. Avoid the loft unless you live up there.
Two‑storey house	On the ground‑floor landing wall or stairway shelf	Height helps upstairs coverage without starving downstairs.
Studio flat	Open shelf away from the microwave and window	One good, open spot usually beats any “neat” hiding place.

What to do if you must use the window area

Sometimes the incoming cable simply doesn’t reach anywhere else and a visit from an engineer isn’t on the cards.

You can still make the best of a bad spot:

• Move the router off the sill itself onto a nearby table or shelf, even 50 cm away from the glass.
• Keep it clear of the radiator and at least a few inches from the wall.
• Open curtains during heavy use so fabric doesn’t swallow signal.
• Angle external antennas slightly inwards, not facing the street.

And if your provider offers a free or low‑cost relocation visit, it’s usually money and time well spent.

Old habits, smarter placement

Putting routers on window sills feels tidy, like parking shoes by the door. It made sense when we only cared about signal in one room. Now that Wi‑Fi runs work, school, games and calls, the placement matters more.

This isn’t about perfection. It’s about nudging a small plastic box into a spot where the whole house benefits. Same router, same bill, different behaviour.

Share the trick and you’ll often find someone whose broadband “suddenly improved” the day an engineer quietly lifted the router off the sill.

FAQ:

• Will moving my router really make more difference than upgrading my package? Often, yes. If your speeds are fine next to the router but poor in other rooms, placement is the bigger issue. A faster package won’t fix signal blocked by walls and windows.
• Is it bad to put the router on the floor instead of the window sill? The floor is usually better than the sill, but still not ideal. Furniture, pets and people block signal at low level. Waist‑height on an open surface nearly always wins.
• Should I use 2.4 GHz or 5 GHz after moving it? Use both if your router supports dual‑band. 2.4 GHz travels further and through walls better; 5 GHz is faster at shorter range. Many routers manage this automatically under one network name.
• Do plants on the window sill affect Wi‑Fi? A couple of small plants won’t matter, but big, leafy ones directly in front of the router can absorb and scatter signal, especially when the soil is damp. Keep a clear line of sight where you can.
• When is it time to replace the router instead of just moving it? If it’s more than five or six years old, only supports older Wi‑Fi standards, or struggles even when you’re in the same room, ask your provider about a newer model. Placement is still important, but old hardware has limits.