A lock with a SIM card to open via Internet?

Swasterix

Bigphil1474 said:
They don't just take a few photos and show people round your house.

That’s the sum total of what they did when I sold my house a few years back. The exception being that I conducted the viewings too. 

In this scenario though, I’d get an agent. 

QQQ

I do know of padlocks that can be opened by SMS or telephone though - used for remote access on isolated substations and storage sites.  Something like https://www.esmeone.com/product/gl-2-gps-gprs-rfid-nfc-lock-padlock/

Thank you for the first technical answer in the thread. Is there anything similar in a sashlock form factor as opposed to padlock?

GDB2222

QQQ said:

I do know of padlocks that can be opened by SMS or telephone though - used for remote access on isolated substations and storage sites.  Something like https://www.esmeone.com/product/gl-2-gps-gprs-rfid-nfc-lock-padlock/

Thank you for the first technical answer in the thread. Is there anything similar in a sashlock form factor as opposed to padlock?

The term you want to search for is Smart Lock. Yale do one. 

FreeBear

GDB2222 said:

QQQ said:

I do know of padlocks that can be opened by SMS or telephone though - used for remote access on isolated substations and storage sites.  Something like https://www.esmeone.com/product/gl-2-gps-gprs-rfid-nfc-lock-padlock/

Thank you for the first technical answer in the thread. Is there anything similar in a sashlock form factor as opposed to padlock?

The term you want to search for is Smart Lock. Yale do one. 

Pretty sure Yale don't do a smart lock that uses 3g/4g connectivity. WiFi and Bluetooth only (I think).

Doing a search for "GSM door lock" turns up a few hits. Didn't find any that are battery operated, and none that are cheap.

GDB2222

FreeBear said:

GDB2222 said:

QQQ said:

I do know of padlocks that can be opened by SMS or telephone though - used for remote access on isolated substations and storage sites.  Something like https://www.esmeone.com/product/gl-2-gps-gprs-rfid-nfc-lock-padlock/

Thank you for the first technical answer in the thread. Is there anything similar in a sashlock form factor as opposed to padlock?

The term you want to search for is Smart Lock. Yale do one. 

Pretty sure Yale don't do a smart lock that uses 3g/4g connectivity. WiFi and Bluetooth only (I think).

Doing a search for "GSM door lock" turns up a few hits. Didn't find any that are battery operated, and none that are cheap.

There’s something called Yale Connect WiFi Bridge, which would work with a MiFi.

Grumpy_chap

QQQ said:

My friend moved abroad and wants to sell his house without spending money on agencies. For that he wants to install a smart lock which he will open remotely over Internet for unattended viewers.
What locks with a 3G SIM card are available on the market and which ones would you recommend? There will be no mains power, so WiFi is not an option.

For selling the house from a distance, the choice to not use an EA seems to me like knowing the price of everything and the value of nothing.  I realise others have commented in similar vein and that is not what the OP wishes to hear.

With regard to the technical options, why will there be no mains power?  I understand the property will be vacant and empty (clear of everything, I assume) but some power may still be required.  Any prospective buyer wishing to view the property may wish to switch lights etc., there may be a need for some background space heating (frost protection).

For smart locks, which is what the OP's friend appears to require, YALE seem to offer the broadest options and possibly the market leader:
https://yalehome.co.uk/smart-locks/
The locks themselves seem to be battery operated but the remote operation seems to require a WI-FI service.  This would not be available if there is no power at the property.  If mains power can be left on, a solution might be a mobile WIFI device permanently plugged in, for example:
https://www.argos.co.uk/product/3424999

Other brands of smart lock are available, but the devices still seem to need WIFI and "hub" to be powered?
https://www.toolstation.com/bold-sx-33-keyless-cylinder-smart-door-lock/p67035

Some of these locks offer good features, such as "door left open / ajar alerts" but what will your friend do if this is received?
Will your friend have someone visit the property periodically to do a check on things?

GDB2222

If the house is unoccupied, any insurance that the op can get would most likely require that the water is fully drained down. So, frost may not be much of an issue. 

victor2

Assuming there is power in the house - and I agree with @Grumpy_chap that there really has to be - as well as a suitable MiFi hub, a wireless camera would also be an option so that the owner can keep an eye on the house and if nothing else, reassure himself that the hub is functioning.