Key takeaways
- Read the signal in dBm rather than bars: on 4G, about −90 dBm or better is good indoors; −105 dBm or weaker means calls will struggle.
- Thick RCC walls, shear walls in high-rises and coated glass all block signal.
- Slow data only at 9 pm points to tower congestion rather than weak signal.
- A typical 2–3 BHK is covered by one kit, and larger homes add a splitter and second indoor antenna.
People check the water pressure, the parking and the view before signing for a flat, then discover after moving in that calls drop in the bedroom and the work laptop's hotspot crawls. Mobile signal is invisible on a site visit, and brokers rarely mention it. Spend ten minutes on the checklist below during your visit, and you will know whether the flat has a signal problem and how expensive it is to fix.
Quick answer
- Test the signal in every room you will actually use, not just the living room near the window, and do one call test from the bedroom.
- Read the signal in dBm rather than bars: on 4G, about −90 dBm or better is good indoors; −105 dBm or weaker means calls will struggle.
- Check your own operator and at least one other, and visit once in the evening if you can.
- Weak signal isn't a deal-breaker if the balcony or roof has 2+ bars. A signal booster can bring it indoors, but you need permission to fit an outdoor antenna.
Why does mobile signal vary so much between flats?
Two flats in the same society can have completely different signal. The differences come from:
- Floor level. Ground and lower floors are often shadowed by neighbouring buildings; very high floors can see too many towers at once, which hurts quality (see why upper floors get weak signal).
- Which side the flat faces. A flat facing the tower gets far more signal than one on the far side of the building.
- Construction. Thick RCC walls, shear walls in high-rises and coated glass all block signal.
- Basements, lift lobbies and inner rooms, where signal is weakest of all.
The 10-minute mobile network checklist
- Turn off Wi-Fi on your phone so you are testing the mobile network.
- Check your signal in dBm in each room: living room, bedrooms, kitchen, study, even the bathroom. Our signal strength checker shows where to find it on Android and iPhone.
- Make a two-minute call from the bedroom with the door closed. Ask the other person whether your voice breaks up.
- Run a speed test in the room you will work from.
- Repeat on the balcony or at the window. A big difference means the building is blocking the signal.
- Test a second operator. Bring a family member's phone, or ask the owner or a neighbour which operator works best.
- Check the lift, the stairwell and the parking if you will take calls there or need OTPs at the gate.
- Visit once in the evening if possible. Slow data only at 9 pm points to tower congestion rather than weak signal.
- Ask neighbours and the RWA whether people complain about network, and whether anyone has installed a booster.
- Note whether fibre broadband is available in the building, for Wi-Fi and Wi-Fi calling.
How to read your results
| Indoor 4G reading (RSRP) | What to expect | Verdict |
|---|---|---|
| −80 dBm or better | Excellent calls and fast data | No problem |
| −80 to −95 dBm | Good, reliable for most use | Fine |
| −95 to −105 dBm | Usable, but slow data and occasional drops in inner rooms | Borderline; check the bedroom carefully |
| −105 to −115 dBm | Frequent call drops, slow or no 4G | Plan a fix before moving in |
| Weaker than −115 dBm / no service | Calls fail indoors | Fixable only if there is signal on the balcony or roof |
Weak signal in a flat you love: deal-breaker or not?
Usually not. Ask yourself one question: is there decent signal on the balcony, terrace or roof? If there are 2 or more bars outside (around −95 dBm or better), a mobile signal booster can pick up that outdoor signal and spread it through the flat. A typical 2–3 BHK is covered by one kit, and larger homes add a splitter and second indoor antenna.
It becomes a real deal-breaker when there is no usable signal even outside for any operator. That is rare in cities but does happen in new projects on the edge of town, before towers come up.
Renting? Questions to ask the landlord
- Can I fix a small antenna on the balcony railing or the roof? The outdoor antenna is about the size of a hand or a small TV antenna, and the cable can run through a window gap or existing conduit.
- Is there a power socket near where the booster would sit?
- Will the society allow roof access for the antenna, if the balcony doesn't face a tower?
A booster isn't a permanent fixture: when you move out, you take it with you and reinstall it in the next home, as long as the operators and area are similar. That makes it a sensible choice for tenants.
Buying? Add it to your due diligence
For buyers, especially in under-construction or newly delivered projects, check signal in a finished sample flat or a neighbouring tower that is already occupied. Ask the builder whether the basement parking and lifts will have in-building coverage. If you work from home, weak signal is worth negotiating over, or at least budgeting for. Our network booster price guide explains what drives the cost.
Moved in already, and the signal is bad?
Run the same checks, note the readings, and send them to us. For most flats the fix takes an afternoon. See our page on network boosters for home, or use the Signal Booster Finder to get a model suggestion in a minute.
Frequently asked questions
How many bars is good enough for a home?
Bars aren't standardised between phones, so use the dBm reading. On 4G, about −95 dBm or better in the rooms you use most is comfortable; weaker than −105 dBm usually means dropped calls and slow data.
Is the signal better on higher floors?
Not always. Middle floors often do best. Low floors can be shadowed by other buildings, while very high floors may "see" several towers at once, which causes interference and poor call quality even with good bars.
Can I install a signal booster in a rented flat?
Yes, with the landlord's permission for the small outdoor antenna. Installation needs no civil work, and you can take the kit with you when you move.
Should I just rely on Wi-Fi calling instead?
Wi-Fi calling is a good backup if the building has reliable fibre, but it stops during power and broadband outages and doesn't help with mobile data, OTPs on the move or visitors' phones. Many households use both. Read our signal booster vs Wi-Fi calling comparison.
Found a weak spot in your new home? WhatsApp your readings to SIGLIFT at +91-9650237601 for a free recommendation. Free shipping across India, cash on delivery and a 10-day return window.
Written by the SIGLIFT technical team — mobile signal booster specialists for Indian networks. Last updated . Questions? Talk to us.
