What to Know About Security Systems for Homes and Businesses

What should you decide before installing a security system?

When you buy a security system you are really making three decisions: what you need to see, how far back you need to be able to look, and what should happen when something occurs. Answer those three and the components choose themselves. Reverse the order and start with the hardware, and you end up with equipment that only partly fits the site.

A concrete example: to watch the till area of a shop closely enough to recognise faces, you need a narrower lens and the right mounting height. In the same shop’s stockroom the goal is not recognising faces but recording movement and time, and a wide angle is fine there. Using two different camera types in one building is both cheaper and more useful than hanging the same camera everywhere.

How many megapixels does a security camera need?

Resolution tells you how many pixels the image contains. It does not tell you how many of those pixels land on the area you actually care about. Point an 8 MP camera at an entire car park through a wide lens and fewer pixels land on a number plate than with a 4 MP camera aimed correctly at the entrance. What determines usable footage is pixel density across the width of the target.

• Lens and field of view: a wide angle covers more ground but kills detail; a narrow one gives detail but leaves blind spots.
• Night performance: real infrared range falls short of the figure on the box, and rain and light pollution shorten it further.
• Wide dynamic range (WDR): where a camera faces glass or a doorway, one without WDR records only a silhouette in daylight.
• Ingress rating: anything facing outdoors should be at least IP66 — Istanbul rain and wind find a weak seal within one winter.
• Cabling: the cross-section, screening and route of the cable determine the system’s life as much as the camera does.

IP or analogue (AHD/TVI)?

On an IP system each camera joins the network, recording goes to an NVR, and one cable carries both data and power (PoE). On an analogue system the picture travels over coaxial cable to a DVR and power is run separately. For most new installations IP makes more sense: the cabling serves devices beyond cameras later, the resolution ceiling is higher, and per-camera settings are more flexible.

But if a building already has sound coaxial cabling in place, upgrading over it with AHD/TVI cameras is usually far cheaper than opening the walls again. The right answer depends on the building, which is why we do not recommend a system type before surveying. We describe how we handle the network side on our network and cabling infrastructure page.

What are the most common camera installation mistakes?

In the overwhelming majority of installations the problem is not the hardware but where and how the camera was mounted. These are the mistakes we see again and again on systems we take over:

• Mounting too high: a camera looking down from four metres records the tops of heads, not faces. For entrance cameras, 2.5–3 metres is usually right.
• Pointing straight at the sun or a street light: the image washes out completely in the early morning, exactly when it is most needed.
• Mounting in front of a surface that reflects infrared: glass, a white wall or a soffit turns the night image into a foggy white.
• Putting the recorder somewhere visible: the first thing an intruder takes is the recorder. The NVR/DVR belongs in a locked cabinet, with off-site backup on critical sites.
• Skipping a UPS: when the power goes, so does the system. A small uninterruptible supply is the cheapest insurance the installation can carry.

How many days should a security camera keep recordings?

Most people do not notice an incident on the day it happens. Stock missing from a store room, damage in an apartment entrance, a scratch along a car — you usually find out days later. At that moment there is only one question: is the footage still there?

Retention depends on the number of cameras, resolution, frame rate, compression (H.265 fits roughly twice as much on the same disk as H.264) and whether you record continuously or on motion. As a rough guide, four 4 MP cameras recording on motion with H.265 will usually hold three to four weeks on a 2 TB disk. Thirty days is a sensible target for a business; fifteen covers most domestic needs. We work through the calculation for your own system step by step in how many days a security camera records.

One detail that gets overlooked: surveillance recording writes continuously. A desktop computer drive will not survive that load for long — the installation needs a disk built for surveillance duty.

Camera or alarm: which one solves what?

Treating cameras and alarms as alternatives is a common mistake. A camera hands you evidence after the event; an alarm intervenes during it. A siren and an instant notification usually end an attempted break-in within the first minute.

Today’s wireless alarm panels can be fitted without opening up the installation again, which is a real advantage in occupied homes and trading businesses. Magnetic contacts go on doors and windows, motion detectors cover interior spaces (pet-immune models exist for households with animals), and smoke and flood detectors can be added at critical points. Our alarm systems page sets out which detector suits which space.

What do intercoms, smart locks and access control do?

In homes and apartment buildings the weakest link is often the door itself. A video door entry system lets you see who is there without opening it — one of the most useful and least expensive improvements available in an apartment block. In a business the question is less about seeing who arrives than about managing who may go where: card or code-based access control separates areas such as stock rooms and offices, and answers who entered when from a log.

We cover both on our intercom and door entry and smart locks and access control pages.

What legal duties does recording CCTV footage create?

This barely comes up in installation quotes, yet it has real consequences for businesses and building management committees. Under Turkey’s personal data protection law (KVKK), recorded footage counts as personal data and whoever keeps it is the data controller.

• Visible signage stating that recording takes place must be displayed at the entrance to the monitored area.
• The frame must cover only the area you are entitled to protect. A camera capturing a neighbour’s door or window, or a whole street, invites complaints and claims.
• Cameras cannot be placed where privacy expectations are high, such as changing rooms, toilets and rest areas.
• Footage should be kept only as long as the purpose requires and deleted automatically when that period ends; an unlimited archive is a liability, not an asset.
• Access to the recordings must be defined, and the recorder kept locked and password protected.

We set the framing to those limits during installation and configure retention so that footage deletes itself on schedule. Our own data handling is set out in our data protection notice.

What maintenance does a camera system need after installation?

Security systems fail quietly. A camera loses focus, a disk stops writing, a detector battery dies — and none of it is noticed until you need the footage. The single most common thing we find on systems we take over is a recorder the owner believes is working that has not recorded for months.

A short check twice a year removes most of that risk: cleaning lenses, testing the night image, checking disk health, confirming actual retention, and testing detector batteries and the siren. We carry those checks out under maintenance and repair, including on systems installed by other companies.

What should you ask before accepting a security quote?

When comparing quotes, the line items underneath the price tell you more than the brand does. We suggest asking:

• How many cameras, with which lens angle, and mounted at which points?
• How many days of footage will this configuration actually hold?
• Where will the cables run, will channels be cut, and what cable type and cross-section is used?
• Where will the recorder be mounted, and how is it protected?
• How long does the system stay up during a power cut?
• Who sets up remote viewing, and who holds the passwords?
• How long is the workmanship guarantee, and what is the response time for a fault?