CCTV Storage Explained — How Many Days You Actually Need
Terabytes, codecs, and frame rates. We demystify the jargon to help you choose the right hard drive for your security system.
You’ve bought the cameras, you’ve chosen the locations, but now comes the technical question that stumps most homeowners: “How big of a hard drive do I need?”
Get it wrong, and you might find that your system has overwritten the footage of last week’s break-in just when you need it most. Or, you might overspend hundreds of dollars on storage you’ll never use.
<!-- The Storage Reality -->
“Storage isn’t just about capacity. It’s about how smart your system is at using it.”
In this guide, we break down the math of CCTV storage, explain why H.265 compression is a game-changer, and show how Ajax NVRs save you money without sacrificing quality.
The 3 Factors That Kill Your Storage
Video files are huge. To understand why, you need to look at three variables: Resolution, Frame Rate, and Compression.
1. Resolution (The Quality)
Everyone wants 4K. But a 4K image has four times as many pixels as 1080p. That means four times the data. If you don’t need to read a license plate from 50 meters away, 2K or 5MP is often the sweet spot for home security.
2. Frame Rate (The Smoothness)
Movies are shot at 24 frames per second (FPS). For security, you rarely need that. Recording at 15 FPS is standard practice; it’s smooth enough to catch detail but cuts your storage needs almost in half compared to 30 FPS.
3. Compression (The Magic)
This is the big one. Older systems used H.264. Modern systems like Ajax use H.265 (HEVC). This technology compresses video files by up to 50% without losing quality. It’s like fitting a double mattress into a shoebox.
Motion Detection: The Space Saver
Do you really need to record 8 hours of an empty driveway every night? Of course not.
Continuous vs. Event-Based
Continuous Recording (24/7): Records everything. Uses maximum storage. Essential for high-risk businesses, but overkill for most homes.
Motion Detection: Only records when the camera sees movement. In a typical residential street, this might only be 2-3 hours of actual footage per day. This can extend your storage duration by 300% or more.
The Ajax NVR Advantage
The Ajax NVR is smart. It allows you to set “JetSparrow” fast retrieval, meaning you can scrub through terabytes of footage instantly. It also supports up to 16TB hard drives, which, combined with H.265 and motion detection, can give you months of retention.
Storage Calculator (Estimated for 4 Cameras)
| Recording Mode | 1TB Drive | 2TB Drive | 4TB Drive |
|---|---|---|---|
| 24/7 Continuous (H.264) | ~4 Days | ~8 Days | ~16 Days |
| 24/7 Continuous (H.265) | ~8 Days | ~16 Days | ~32 Days |
| Motion Only (H.265) | ~25 Days | ~50 Days | ~100+ Days |
Evolution of Video Storage
The Old Way (H.264)
- Large Files
- High Bandwidth
- Expensive Drives
- Short Retention
The Ajax Way (H.265)
- Smart Compression
- Low Bandwidth
- Efficient Storage
- Long Retention
The Verdict: Aim for 30 Days
For most homeowners, a retention period of 14 to 30 days is ideal. This covers you for holidays and gives you time to notice if something went missing from the shed weeks ago.
Our Recommendation
Don’t skimp on the hard drive. The price difference between 2TB and 4TB is small compared to the value of the evidence you might lose. Pair a 4TB Surveillance Grade Drive with an Ajax NVR, set it to Motion Detection with H.265, and you’ll likely have months of footage at your fingertips.
Storage is cheap; lost evidence is expensive.
Need a system that remembers everything? Contact Sipko Security to upgrade to an Ajax NVR today.
Frequently Asked Questions
Can I use a regular PC hard drive?
No. You must use a “Surveillance Grade” drive (like WD Purple or Seagate SkyHawk). Regular PC drives are designed to run for 8 hours a day. Surveillance drives are built to run 24/7 and handle the constant writing of video data without failing.
What happens when the drive is full?
All modern NVRs, including Ajax, have a “Loop Recording” feature. This automatically overwrites the oldest footage with the newest. You don’t need to manually delete anything; the system manages itself.
Does audio take up much space?
Compared to video, audio takes up a negligible amount of space. Enabling audio recording on your cameras will have almost no impact on your storage duration.
Official Government Sources & References
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OAIC – Retention of Footage
Guidelines on the privacy principles regarding the collection and retention of personal information via security cameras.
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Digital Video Surveillance Standards
Technical standards for digital video quality, compression, and storage management.
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eSafety Commissioner – Secure Storage
Advice on securing the storage of surveillance footage to prevent unauthorized access and abuse.
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ACMA – Equipment Standards
Australian standards for electronic equipment, ensuring compatibility and reliability of NVRs and storage devices.
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Victoria Police – CCTV Guidelines
Recommendations for CCTV system setup, including image quality and retention periods to assist police investigations.
