Home Server Power Consumption Guide

Quick Summary

A modern self-hosting setup costs $6-50/year in electricity, depending on your hardware:

Hardware	Idle Power	Annual Cost ($0.12/kWh)
Raspberry Pi 5	4-5W	$4-5
Intel N100 mini PC	6-8W	$6-8
Intel N305 mini PC	8-12W	$8-13
Synology 2-bay NAS (with HDDs)	15-20W	$16-21
Synology 4-bay NAS (with HDDs)	28-35W	$29-37
DIY NAS, 4x HDD	30-40W	$32-42
DIY NAS, 8x HDD	50-70W	$53-74
Used Dell OptiPlex Micro	20-35W	$21-37
Used tower server (Dell PowerEdge)	80-150W	$84-158

The takeaway: Mini PCs and ARM boards cost pocket change to run. NAS devices scale linearly with drive count. Old tower servers are electricity hogs — the annual power bill often exceeds the hardware’s resale value.

How to Calculate Your Costs

The Formula

Annual cost = Watts × 8.76 hours/year × electricity rate ($/kWh)

Where 8.76 = 8,760 hours in a year ÷ 1,000 (to convert W to kW).

Simplified: Annual cost = Watts × 8.76 × rate

Electricity Rates by Region

Region	Average Rate ($/kWh)
US average	$0.12
US (California)	$0.25
US (Louisiana)	$0.08
UK	$0.28 (£0.22)
Germany	$0.35 (€0.32)
Australia	$0.22 (A$0.33)
Canada	$0.10 (C$0.13)
India	$0.08 (₹6.5)

Your costs will vary. Check your electricity bill for your actual rate. The tables in this guide use $0.12/kWh (US average). Multiply by your rate ratio for local costs — if you pay $0.24/kWh, double all cost figures.

Measuring Your Actual Power Draw

Don’t rely on spec sheets — measure actual power consumption with a plug-in power meter:

Kill A Watt P3 P4400 (~$25) — the standard recommendation. Plug your server into it, read the wattage display.
Shelly Plug S (~$20) — smart plug with power monitoring. Track consumption over time via the app.
Any smart plug with energy monitoring — TP-Link Kasa, Tapo, etc.

Spec sheets list TDP (thermal design power), which is the maximum heat the CPU can produce — not the actual power draw of the system. Real idle power is typically 30-60% of TDP for the CPU alone, and the system has other components drawing power.

Power Draw by Hardware Category

Mini PCs

Mini PCs are the most power-efficient general-purpose servers:

Model	CPU	Idle	5-10 Containers	Full Load	Annual (Idle)
Beelink S12 Pro / EQ14	N100/N150	6-8W	8-12W	15-18W	$6-8
Beelink EQ12	N100 (dual 2.5GbE)	6-8W	9-13W	16-20W	$6-8
Beelink EQ12 Pro	N305	8-12W	12-18W	30-40W	$8-13
Beelink SER5 Pro	Ryzen 5 5560U	10-15W	15-22W	35-45W	$11-16
Minisforum UM790 Pro	Ryzen 9 7940HS	15-22W	20-30W	55-75W	$16-23

Why so efficient? Modern mobile CPUs (N100, Ryzen U-series) are designed for laptop battery life. They aggressively power-gate unused cores and subsystems. At idle, an N100 system consumes less power than a single incandescent light bulb.

Raspberry Pi

Model	Idle	Light Use	Full Load	Annual (Typical)
Pi 4 (4 GB)	3-4W	4-5W	6-7W	$4-5
Pi 5 (8 GB)	3-5W	5-7W	10-12W	$5-7

The Pi 5 is marginally more efficient than a mini PC at idle (3-5W vs 6-8W), but the difference is ~$2-3/year. Not enough to outweigh the mini PC’s performance advantage. See our Raspberry Pi vs Mini PC comparison.

NAS Devices

NAS power consumption is dominated by drives, not the NAS CPU:

Configuration	System Idle	Per HDD (idle)	Per HDD (active)	Total Idle
Synology DS224+ (2x HDD)	10W	4-5W	6-8W	18-20W
Synology DS423+ (4x HDD)	12W	4-5W	6-8W	28-32W
Synology DS923+ (4x HDD)	14W	4-5W	6-8W	30-34W
DIY NAS N305 (4x HDD)	12-15W	4-5W	6-8W	28-35W
DIY NAS N305 (8x HDD)	12-15W	4-5W	6-8W	44-55W
Synology DS1821+ (8x HDD)	20W	4-5W	6-8W	52-60W

HDD hibernation can cut idle power significantly. If you have drives that aren’t accessed for hours at a time, enabling spindown reduces per-drive idle power from 4-5W to 0.5-1W. A 4-bay NAS with 2 sleeping drives drops from 30W to 22W.

SSD vs HDD power: Replacing HDDs with SSDs saves 3-4W per drive. An all-SSD NAS idles at roughly half the power of an all-HDD NAS. But SSDs cost 5-10x more per TB — the electricity savings don’t justify the price premium for bulk storage.

Used Enterprise/Desktop Hardware

System	CPU	Idle	Load	Annual (Idle)
Dell OptiPlex 7050 Micro	i7-7700T	20-30W	50-65W	$21-32
Dell OptiPlex 5060 Micro	i5-8500T	18-28W	45-60W	$19-29
Lenovo ThinkCentre M720q	i5-8500T	18-25W	45-55W	$19-26
HP EliteDesk 800 G4 Mini	i5-8500T	18-25W	45-55W	$19-26
Dell PowerEdge R720 (2x E5-2650v2)	2x Xeon	120-150W	300-500W	$126-158
HP ProLiant DL360 Gen9 (E5-2620v3)	1x Xeon	80-100W	200-350W	$84-105
Dell PowerEdge T620 (E5-2630v2)	1x Xeon	90-130W	250-400W	$95-137

Used mini desktops (OptiPlex Micro, ThinkCentre Tiny) are a reasonable middle ground — 2-4x the power of an N100 mini PC but much cheaper to buy ($100-200 used). See our Dell OptiPlex guide.

Used rack servers are expensive to run. A PowerEdge R720 at 130W idle costs $137/year — nearly the purchase price of the server itself. After 2-3 years, you’ve spent more on electricity than the hardware cost. For home use, avoid rack servers unless you need specific enterprise features (many PCIe slots, ECC RAM, IPMI/iDRAC).

The Full Stack: What Does a Complete Setup Cost?

Minimal Setup (Pi-hole only)

Component	Power
Raspberry Pi 4	4W
Total	4W → $4/year

Typical Self-Hoster

Component	Power
N100 mini PC (Docker host)	8W
Total	8W → $8/year

Enthusiast Homelab

Component	Power
N305 mini PC (Docker/VMs)	12W
Synology DS423+ NAS (4x 8TB HDD)	30W
Network switch	8W
Total	50W → $53/year

Serious Homelab

Component	Power
Ryzen 9 mini PC (Proxmox)	25W
DIY NAS, 8x HDD (TrueNAS)	55W
Managed switch (PoE)	15W
UPS overhead	5W
Access point	8W
Total	108W → $114/year

Reducing Power Consumption

1. Choose Efficient Hardware

The single biggest factor. An N100 at 8W idle vs an old Xeon at 100W idle is a 12x difference. Buying power-efficient hardware is the best investment.

2. Enable HDD Spindown

Configure idle HDDs to spin down after 15-30 minutes of inactivity:

Synology: Control Panel → Hardware & Power → HDD Hibernation
TrueNAS: System Settings → Advanced → Disk → HDD Standby
Linux: hdparm -S 240 /dev/sdX (20 minutes)

Saves 3-4W per sleeping drive.

3. Reduce Unnecessary Services

Every running container and service adds CPU wake-ups. Disable or stop services you’re not actively using. A server running 5 containers uses measurably less power than one running 25.

4. Use SSDs for Boot and Docker

Spinning up an HDD for Docker operations when the container data is small wastes power. Keep the OS and Docker volumes on an SSD, and use HDDs only for bulk storage that’s accessed less frequently.

5. Use Efficient Power Supplies

Desktop PSUs waste power through conversion inefficiency. An 80+ Gold PSU wastes 10-15% of input power as heat. An 80+ Titanium wastes only 6%. For a 50W load:

80+ (standard): ~8W wasted → 58W from the wall
80+ Gold: ~5W wasted → 55W from the wall
80+ Titanium: ~3W wasted → 53W from the wall

Mini PCs use external barrel-jack adapters with typically 85-90% efficiency. Not much you can do here.

6. Consolidate Devices

Running one N305 mini PC as both your Docker host and NAS (with USB-attached drives) uses less power than running a separate mini PC + NAS device. The trade-off is less storage expandability and no hot-swap.

UPS and Power Protection

A UPS (Uninterruptible Power Supply) keeps your server running during brief power outages and enables clean shutdowns during extended outages. This prevents data corruption, especially for databases and ZFS pools.

UPS adds 3-10W of overhead from its own electronics and battery charging. Factor this into your power calculations.

Recommended for home servers:

APC Back-UPS BE600M1 (600VA) — ~$65 — enough for a mini PC + NAS for 15-30 minutes
CyberPower CP1500AVRLCD (1500VA) — ~$170 — for larger setups with multiple devices

Runtime estimation: A 600VA UPS provides approximately:

Mini PC (10W load): ~45 minutes
Mini PC + 4-bay NAS (40W load): ~15 minutes
Full homelab stack (100W load): ~5 minutes

See our Best UPS for Home Servers guide.

FAQ

How much does it cost to run a home server 24/7?

$6-50/year for modern, efficient hardware (mini PC + optional NAS). $80-160/year for old tower or rack servers. The biggest variable is whether you have spinning hard drives and how many.

Is self-hosting cheaper than cloud services?

Almost always, once you account for the services you’re replacing. A Nextcloud + Jellyfin + Vaultwarden + Pi-hole stack on an N100 mini PC costs ~$8/year in electricity. The cloud equivalents (Google One + streaming services + password manager + ad blocker subscriptions) cost $200+/year.

Does a server use a lot of electricity?

A modern mini PC uses about the same electricity as a phone charger. An old enterprise server uses about the same as a space heater. Choose accordingly.

Should I turn my server off at night?

No. The power savings are minimal (a few watts × 8 hours = pennies per night), and many self-hosted services (Pi-hole, VPN, monitoring) are useful 24/7. The wear from daily power cycling may reduce hardware lifespan more than continuous operation.

How do I monitor power consumption over time?

Use a smart plug with energy monitoring (Shelly Plug S, TP-Link Kasa, Tapo P110). These log power consumption hourly and calculate monthly/yearly totals. You can also monitor from within your homelab using Home Assistant with an energy monitoring integration.