Docker containers themselves consume negligible power - the cost question is really about what hardware they run on and for how long. A container is just a process. Running five Docker containers on a Synology DS925+ costs the same as running the NAS idle, plus a small CPU and RAM overhead per active container. The meaningful power draw comes from the underlying hardware: NAS models range from 8W idle (ARM entry-level) to 30W+ under load (x86 with spinning drives). This guide gives you the numbers to calculate your actual electricity cost and identify the containers where 24/7 operation is worth it versus where scheduled or on-demand operation makes more sense.
In short: An x86 NAS running Docker 24/7 draws roughly 15-25W under typical multi-container load. At the Australian average residential electricity rate of around $0.30/kWh, that works out to $40-65 AUD per year. Entry-level ARM NAS hardware draws 8-12W with containers running, costing $20-30 AUD per year. The container overhead itself adds roughly 2-5W per active container beyond idle NAS draw. Most containers are worth running 24/7; the exceptions are resource-hungry workloads like video transcoding or AI model inference that can be triggered on-demand instead.
Note on electricity rates: Australian electricity rates vary significantly by state and retailer. The figures in this article use $0.30/kWh as a representative rate. Check your latest electricity bill for your actual rate. Western Australian and Tasmanian rates differ notably from NSW and VIC. Calculated annual costs scale linearly: if your rate is $0.35/kWh, multiply the figures below by 1.17.
NAS Hardware Power Draw: The Baseline
Before calculating container costs, understand your hardware baseline. NAS power draw has three components:
- Idle system power: CPU at minimal utilisation, RAM powered, no active disk I/O. This is the floor everything else builds on.
- Drive spin-up and active I/O: HDDs add 5-8W per drive when spinning, 0.5W when parked. SSDs add 1-2W active. Most NAS setups with mixed drives spend significant time with HDDs parked if containers are not doing continuous I/O.
- Container CPU/RAM overhead: Most background containers (Nextcloud, Vaultwarden, Home Assistant) draw minimal CPU when idle, adding 1-3W each. CPU-intensive containers (Plex transcoding, Jellyfin, AI inference) can add 10-20W or more during active use.
NAS Hardware Idle Power Draw by Category
| Entry ARM (e.g. DS223J) | Mid x86 (e.g. DS425+) | Performance x86 (e.g. DS925+) | High-end x86 (e.g. DS1525+) | |
|---|---|---|---|---|
| Typical idle (no HDD spin) | 7-9W | 13-16W | 15-18W | 18-22W |
| Idle with 2x HDD spinning | 17-21W | 23-28W | 25-30W | 28-34W |
| Under CPU load (Docker active) | 12-18W | 20-30W | 25-35W | 30-45W |
| Annual cost at idle (no HDD). AUD $0.30/kWh | ~$18-24 | ~$34-42 | ~$39-47 | ~$47-58 |
| Annual cost under load. AUD $0.30/kWh | ~$31-47 | ~$53-79 | ~$66-92 | ~$79-118 |
| Docker support | No (ARM, limited) | Yes (full) | Yes (full) | Yes (full) |
| RAM capacity (max) | 2GB (fixed) | 8GB | 32GB | 64GB |
Power Cost Per Container Type
Not all containers are equal in power terms. The difference is between containers that sit idle most of the time (web servers, password managers, sync servers) versus containers that actively process data (media servers, AI tools, monitoring with frequent polling). The following are measured or well-documented estimates for common self-hosted applications running on mid-range x86 NAS hardware:
| Nextcloud (AIO or standard) | Idle: 1-2W above baseline. Light usage spikes to 3-5W. Annual cost addition: ~$3-8 AUD. Worth running 24/7: yes. |
|---|---|
| Vaultwarden (Bitwarden-compatible) | Idle: under 0.5W. Essentially invisible in power measurements. Annual cost addition: under $2 AUD. Worth running 24/7: yes. |
| Home Assistant | Idle: 1-3W above baseline (depends on integrations and automations). With many active integrations: 3-6W. Annual cost addition: $3-12 AUD. Worth running 24/7: yes. |
| Tailscale (container mode) | Under 0.5W. Background process only. Annual cost addition: under $2 AUD. Worth running 24/7: yes. |
| Jellyfin / Plex (media server) | Idle (no transcoding): 1-3W. Active software transcoding: 10-25W additional. Hardware transcoding (Intel QSV): 3-8W additional. Annual idle cost addition: $3-8 AUD. Transcoding sessions cost extra. 2-hour movie at 15W software transcode = ~$0.009. Worth running 24/7: yes for idle; transcoding sessions are on-demand anyway. |
| Immich (photo management) | Idle: 1-2W. Machine learning tasks (face recognition, CLIP): 15-30W burst during initial processing, then idle. Annual cost addition (post-setup): $3-8 AUD. Worth running 24/7: yes, ML processing runs on first use then scales back. |
| Uptime Kuma (monitoring) | Under 1W. Minimal CPU, mostly sleeping between checks. Annual cost addition: under $3 AUD. Worth running 24/7: yes. |
| Portainer | Under 0.5W when idle. Annual cost addition: under $2 AUD. Worth running 24/7: yes (management interface only). |
| Ollama / local LLM inference | Idle (model loaded, no queries): 2-5W. During inference: 30-100W+ depending on GPU passthrough or CPU inference. Annual cost for on-demand use: varies significantly. Worth running 24/7 with model loaded: borderline. Consider loading on-demand if used infrequently. |
Calculating Your Own Annual Container Cost
The formula is straightforward:
Annual cost (AUD) = Watts × 8,760 hours ÷ 1,000 × your electricity rate per kWh
Example: A DS425+ running three containers (Nextcloud, Vaultwarden, Home Assistant) with two HDDs in HDD sleep mode most of the time.
- Baseline idle (system + drives parked): 14W
- Container overhead (3 containers): +4W
- Total: 18W
- Annual energy: 18W × 8,760h ÷ 1,000 = 157.7 kWh
- Annual cost at $0.30/kWh: 157.7 × 0.30 = $47.30 AUD per year
Add drive spin-up time (if HDDs spin for database access a few hours per day): +6W for 4 hours = +0.024 kWh/day = +$2.63/year. Effectively rounding error for most setups.
Australian Electricity Rates by State
Approximate Residential Electricity Rates. Australia 2025-26
| NSW/ACT | VIC | QLD | SA | WA | |
|---|---|---|---|---|---|
| Typical usage rate (per kWh) | $0.28-0.35 | $0.28-0.34 | $0.28-0.33 | $0.38-0.50 | $0.28-0.32 |
| Annual cost: 18W 24/7 | $41-51 | $41-49 | $41-48 | $55-73 | $41-47 |
| Annual cost: 25W 24/7 | $57-71 | $57-68 | $57-66 | $76-101 | $57-65 |
| Annual cost: 35W 24/7 | $80-100 | $80-96 | $80-93 | $107-141 | $80-91 |
South Australia's notably higher electricity rates (up to $0.50/kWh on some tariffs) mean a SA user running the same 25W setup pays up to $101/year versus $57 for an equivalent NSW setup. For SA users, hardware efficiency is proportionally more valuable. Choosing a lower-draw NAS or enabling HDD sleep aggressively has a larger dollar impact.
When to Run 24/7 vs On-Demand
Most home server containers should run 24/7. The overhead is small, and the operational benefit (availability when you need it, background sync, automations) is real. The containers worth reviewing for on-demand operation are those with high active-state power draw that you use infrequently:
- Local LLM inference (Ollama, etc.): If you query a local model occasionally rather than continuously, loading the model and stopping the service between sessions saves meaningful power. A 50W inference load used 2 hours per day costs $11/year; leaving it running 24/7 at 5W idle costs $13/year. Similar in this case, but scales with model size and GPU draw.
- Video transcoding jobs: Handbrake, FFmpeg, or conversion queues should be run as jobs rather than persistent services. Trigger them via cron or manually, not as always-on services.
- Development environments: Database servers and app stacks spun up for testing should be stopped when not in use. A Postgres container at idle is cheap; a development stack with hot reload and frequent queries is not.
For everything else. Nextcloud, Vaultwarden, Home Assistant, media servers, monitoring, reverse proxies. Running 24/7 is the right default. The power cost is genuinely small and the convenience is significant.
Reducing Power Consumption Without Reducing Functionality
Practical steps to reduce 24/7 Docker power draw without compromising functionality:
- Enable HDD hibernation: Synology Control Panel → Hardware and Power → HDD Hibernation. Setting drives to sleep after 20 minutes of inactivity saves 5-8W per HDD most of the time. Most containers do not generate continuous I/O, so drives sleep naturally between accesses.
- Consolidate containers onto fewer NAS devices: Running two NAS devices at 18W each costs $95/year. Running one NAS at 25W costs $66/year. Consolidation before adding more hardware pays off quickly.
- Use SSDs for the system volume: An NVMe cache or SSD system volume eliminates spinning drive noise and eliminates the 5-8W HDD spin-up cost during OS and Docker image access. HDDs can then be used for bulk data and sleep more aggressively.
- Avoid idle containers you don't actually use: A pulled-but-unused container sitting at 1W adds $2.60/year. Over a typical self-hosters stack of 15 containers with 5 genuinely unused, that's $13/year for nothing.
Related reading: our NAS buyer's guide, our NAS power consumption guide, and our NAS explainer.
Use our free NAS Power Calculator to calculate your exact running costs.
How much does it cost to run a Synology NAS with Docker 24/7 in Australia?
For a mid-range x86 Synology (DS425+, DS925+) running several Docker containers with drives in sleep mode most of the time, expect 15-22W average draw. At $0.30/kWh that works out to $40-58 AUD per year. Adding active HDD use (drives spinning 4-8 hours per day) adds roughly $10-20/year. A DS925+ running a full self-hosted stack (Nextcloud, Vaultwarden, Home Assistant, Jellyfin, Immich) costs approximately $50-70/year in electricity for most Australian states.
Does running more Docker containers significantly increase power use?
Not significantly for typical home server containers. Each idle container adds roughly 0.5-2W above the NAS baseline. Running 10 containers versus 3 might add 5-10W total if they are all background services (Nextcloud, Vaultwarden, reverse proxy, monitoring). The meaningful increases come from containers that actively process data. Plex transcoding, Immich machine learning, or LLM inference. Those can add 10-30W during active use, but that use is typically brief and on-demand rather than continuous.
Is it cheaper to run Docker on a NAS or on a dedicated mini PC?
A dedicated mini PC (Intel N100-based, like a Beelink EQR6 or similar) draws 8-15W idle and runs x86 Docker natively without NAS overhead. At 10W draw, annual cost is $26/year at $0.30/kWh. Cheaper than a NAS running the same containers. However, you lose the NAS's storage management, RAID, and backup integration. The practical answer: if you already have a NAS, run Docker on it. If you are building from scratch and only need containers without a large NAS storage requirement, a mini PC is the more power-efficient choice for the compute portion.
Can I reduce NAS power use by scheduling containers to stop overnight?
Yes, for containers where overnight availability is not needed. Synology's Task Scheduler and QNAP's equivalent can run docker stop container-name and docker start container-name on a schedule. A container stopped for 8 hours per day (instead of running 24/7) saves roughly 33% of its power draw. For a 3W container, that's about $2.30/year. The savings are modest for individual containers but meaningful if you stop 5-10 non-critical containers overnight.
Does running Plex or Jellyfin 24/7 cost significantly more than other containers?
Only when actively transcoding. The media server container itself idles at 1-3W. Transcoding a single stream in software adds 10-25W for the duration of playback. At $0.30/kWh, a 2-hour software-transcoded movie costs approximately $0.008-0.015. Effectively nothing per view. Hardware transcoding (Intel Quick Sync on x86 NAS) adds only 3-8W per stream and is significantly cheaper. If your NAS supports hardware transcoding, enabling it in Plex or Jellyfin settings substantially reduces both power use and thermal load during playback.
Running Docker containers requires a NAS with sufficient RAM and an x86 processor. For Australian pricing and model comparisons on Docker-capable Synology and QNAP hardware, see the current buying guide.
Best NAS for Docker in Australia