If you're thinking about starting a project with a Raspberry Pi or upgrading the one you already have, it's easy to get carried away by the marketing, buy the latest model with all the official accessories, and in the end, spend considerably more money and energy than necessaryFortunately, by understanding how the hardware behaves and fine-tuning the configuration, you can save a lot without sacrificing stable operation.
Throughout this article we will see, based on real cases and consumption data, How to avoid overspending on Raspberry PiChoosing the right model, reducing power consumption, optimizing your network, avoiding absurd bottlenecks, getting the most out of SSDs and SD cards, and even estimating how much it will cost to keep your Pi powered on 24/7. All in a practical way, with specific commands and clear explanations so you don't have to go in blind.
Choose the right Raspberry Pi to avoid paying for power you won't use.
One of the first decisions that will have the biggest impact on your wallet is choosing the model. The Raspberry Pi 5 is a little beast: a quad-core Broadcom BCM2712 processor at 2,4 GHz, dual HDMI output, up to 16 GB of RAM, and a PCIe bus for advanced storage. But in practice, Many home projects don't even come close to harnessing all that performance.Therefore, paying its price and its extra consumption may be unnecessary.
If what you want is to set up a DNS server with Pi-hole To block ads across your entire network, the workload is minimal: it's basically redirecting and filtering DNS requests. This type of service works perfectly even on a Raspberry Pi Zero 2W...much cheaper and more efficient. Buying a Pi 5 just for that is overkill.
With Home Assistant Something similar happens. Although more RAM can be beneficial in very complex installations full of automation and devices, for an average home with light bulbs, smart plugs, and a few sensors, a Raspberry Pi 3 B or 3 B+ With 1 GB of RAM, it still performs smoothly. Only if you plan on a very large home automation system or use many resource-intensive accessories would it make sense to consider a higher-end model.
In the realm of emulation, most users simply want to enjoy classic consoles like the NES, SNES, Mega Drive, or PlayStation 1. It handles all of that effortlessly. Raspberry Pi 3 B + With RetroPie or similar software. Only if you intend to emulate Dreamcast, Nintendo 64, or more modern systems decently does the Pi 5 start to make sense. For everything else, paying more is an unnecessary luxury.
You also have to take into account the energy consumption of each modelA Pi 5 needs a power supply up to 27WWhereas a Pi 3 B is powered by 5V/2,5A (around 12,5W theoretical maximum) and in practice consumes considerably less power under sustained conditions. For systems that will be running 24/7, such as lightweight home servers, this difference translates into significant savings over the course of the year.
In short, unless you're going to work with AI, intensive processing, or serious use of the PCIe busOften it is more sensible to use older models (3 B, 3 B+, ​​Zero 2 W, even 4 depending on the case) and reserve the Pi 5 for projects that really take full advantage of its power.
How to reduce power consumption and stabilize a Raspberry Pi 3 B+
There are curious situations where the bottleneck isn't the processor, but the power supply itself. A very illustrative case is that of a Raspberry Pi 3 B+ connected with a long power cable (about 3 meters)These cables often cause noticeable voltage drops, and that, combined with certain network conditions, can make the system unstable.
In this scenario, it was observed that the Pi 3 B+ worked well while the Consumption remained below about 0,5 AHowever, as soon as it approached that limit, the network interface began to fail, the LAN dropped, and the board entered boot loops. The goal was to achieve a stable system that consumed between 0,34 and 0,4 A, enough to use it as an internet radio player with VLC, connected via HDMI to an inexpensive soundbar and controlled from an Android phone.
The most striking finding was that consumption rose significantly when the The Ethernet link was operating in gigabit mode (1000 Mbps)By forcing the connection to 100 Mbps full duplex, it was possible to reduce consumption enough to avoid network drops and keep the Pi stable even under high load (about 0,45 A).
Configuring /boot/config.txt to save power
A key part of the adjustment involved modifying the file /boot/config. txt to disable unnecessary components and lower frequencies and voltages. The idea isn't to push the Pi to its limits, but quite the opposite: underuse it in a controlled way so that it consumes less and doesn't push the power supply or cable to its limits.
The parameters used were similar to these (it would be edited with sudo nano /boot/config.txt):
Example of energy saving settings on Raspberry Pi 3 B+:
Disable WiFi and Bluetooth via software using specific overlays:
dtoverlay=pi3-disable-wifi
dtoverlay=pi3-disable-bt
Reduce CPU frequency and limit its operating range:
arm_freq=900
arm_freq_max=900
arm_freq_min=150
Lower GPU frequencies and related buses:
gpu_freq=250
core_freq_min=250
sdram_freq_min=250
Adjust core voltage to reduce power consumption (negative values ​​mean undervolt):
over_voltage=-3
over_voltage_min=-8
Parameters such as initial_turbo (for example, 30) to allow the CPU to run fast only for a few moments at startup, and temp_limit (for example, 60) to force the system to reduce performance if the temperature reaches a certain threshold. With all this, the Pi was able to operate most of the time at 150 MHz, occasionally boosting to 900 MHz, without VLC experiencing any interruptions when playing audio, even when using all four cores simultaneously.
Force Ethernet to 100 Mbps to cut power consumption
What is not as well documented is the impact of the 1 Gbps Ethernet interface on power consumption. In this practical experience, it was observed that Negotiating the gigabit connection significantly increased the demand for energy...to the point of making the board unstable when using a "bare" power supply. Forcing the link to 100 Mbps provided some margin.
On systems based on Debian/Raspberry Pi OS, the network interface can be adjusted in / etc / network / interfaces to set speed and operating mode. A typical example would be:
the car
iface lo inet loopback
self eth0
ALLOW-HOTPLUG ETH0
inet dhcp iface eth0
link-speed 100
link-duplex full
With this, the Raspberry Pi always negotiates at 100 Mbps full duplexFor a simple internet radio player, a lightweight server, or similar services, 100 Mbps is more than enough. In return, the reduced power consumption helps ensure system stability even with long cables or limited power supplies.
In periodic monitoring tests using checkvolts.sh scripts, the core voltage was found to remain around 1,0 V and the SDRAM memories around 1,25 V, with the CPU running almost all the time at 150 MHz and only a tiny percentage of the time at 900 MHz, while audio playback remained smooth at 100% CPU usage.
Automate network setups and VLC on startup
To complete the internet radio project, the following was used /etc/rc.local To mount Samba network resources and start VLC in HTTP control mode at system startup. After a short delay, the shared music folders and M3U playlists are mounted, and VLC is launched.
Sleep 10
sudo mount -t cifs -o guest //192.168.1.13/musicshare /home/pi/Desktop/All\ Music/
sudo mount -t cifs -o guest //192.168.1.13/m3urepository /home/pi/Desktop/Streaming/
sudo -u pi vlc -I http –http-password password &
This approach allows the Raspberry Pi to boot up and, without user intervention, have the network music library and a VLC accessible from mobile via browser or client appwith very low power consumption and sufficient stability to forget about it on top of a wardrobe.
Turn off WiFi, Bluetooth, Ethernet and USB to save energy
Another direct way to avoid overspending on a Raspberry Pi is turn off what you don't needMany projects don't require Wi-Fi, Bluetooth, or even USB ports if the Pi is used only as a network node or embedded device. Disabling interfaces can save a few hundred milliamps, which translates into significant savings over 24/7 operation.
Of course, it should be borne in mind that Continuously activating and deactivating interfaces also has a cost.If you're constantly turning Wi-Fi or Ethernet on and off every few minutes, the extra energy cost of these initialization cycles can eat up some of the savings. The sensible thing to do is disable anything that won't be used consistently or for very long periods.
Turn Bluetooth off and on
To easily manage Bluetooth and WiFi at the system level, you can use rfkillAll commands must be run as administrator, so if you are not root, add sudo in front of:
Disable Bluetooth:
rfkill block bluetooth
Reactivate it:
rfkill unblock bluetooth
If your project doesn't use any Bluetooth peripherals (mice, keyboards, controllers, sensors…), it makes sense keep it permanently locked to reduce power consumption and radio noise.
Turn WiFi off and on
The procedure is similar for the wireless network. If you always use a wired connection or the Pi is in a place where you don't use Wi-Fi, you can turn it off:
Turn off WiFi:
rfkill block wifi
Re-enable WiFi:
rfkill unblock wifi
When you turn WiFi back on, you will have to reconnect to your network (for example, using the graphical tool or by editing wpa_supplicant.conf). This minor drawback is offset if you're looking to reduce power consumption on devices that are on all day.
Disable the Ethernet interface via software
If the opposite is true for you and you only use WiFi, or there are simply times when you prefer to turn off the wired interface, you can do so with ifconfig (or IP in newer systems):
Disable Ethernet:
ifconfig eth0 down
Activate Ethernet:
ifconfig eth0 up
This does not cut power to the Ethernet controller at the physical level, but it does It stops traffic and package handling, which slightly reduces activity and associated consumption.
Completely turn off USB ports (and associated Ethernet)
On many Raspberry Pis, the power supply for the USB ports and the Ethernet controller is shared. This means that If you cut the power to the USB ports, the Ethernet port will also lose power.This may be of interest to you if you use the Pi in purely embedded mode without external peripherals.
To disable USB ports at the kernel driver level, paths in /sys can be used:
Disable USB ports:
echo '1-1' | sudo tee /sys/bus/usb/drivers/usb/unbind
Reactivate them:
echo '1-1' | sudo tee /sys/bus/usb/drivers/usb/bind
The identifier 1 - 1 This corresponds to the root USB hub on many Raspberry Pi models, which disconnects all ports at once. Only use it if you're sure you don't need it. no USB devices or wired networkbecause you'll lose both at the same time.
Prevent the Raspberry Pi from consuming extra CPU when booting from SSD
On Raspberry Pi 3 and 4, it is very common to replace the microSD card with a SSD connected via USB to gain speed and reliability. However, some users are encountering strange behavior: the CPU seems busier than it should be, and the motherboard's green LED blinks constantly, even when the system is seemingly idle.
A typical case showed load values ​​(load average) remarkably high for a newly booted system with no real activity. For example, after five minutes of operation, the uptime output was something like:
09:54:17 up 5 min, 1 user, load average: 0,60, 0,52, 0,44
Inspecting processes with ps revealed kernel threads and storage-related processes using CPU periodically, and the system activity LED was continuously turning on and off, indicating constant I/O access.
The cause: the Pi keeps checking the microSD slot.
After investigation, it was discovered that when the Raspberry Pi boots from a SSD or USB device and there is no microSD card insertedThe system assumes that a card may appear at any time. As a result, it continuously checks the SD slot to see if a card has been inserted, which generates extra CPU usage and green LED activity.
This behavior can involve up to 10% additional CPU usage in some casessimply due to the constant scanning of the card reader. For equipment that operates 24/7, this unnecessary load generates extra heat and wastes resources.
Quick fix: Insert an empty microSD card
The easiest way to stop these checks is leave a microSD card insertedEven if you don't use it to boot or store anything on it, simply insert an empty microSD card into the slot and restart the Raspberry Pi to stop it from repeatedly asking if there's a card.
With this simple gesture, the system already detects a medium present and There is no need to continue managing insertion eventsreducing CPU load and I/O activity.
More elegant solution: dtparam=sd_poll_once
If you prefer not to rely on a physical microSD card or simply want to control the behavior from the settings, you can use a device parameter in /boot/config. txt called sd_poll_onceThe idea is that the Raspberry Pi only checks for the presence of an SD card during boot and then stops doing so.
To apply it, edit the configuration file with:
sudo nano /boot/config.txt
And add the line:
dtparam=sd_poll_once
Save the changes, restart, and the system will stop performing continuous polls. In the tests performed, after activating this parameter, the load values ​​dropped drastically. For example, using uptime again yielded readings like these:
09:54:17 up 5 min, 1 user, load average: 0,02, 0,11, 0,06
That is to say, a system practically at restThere are no more constant green LED flashes or kernel processes consuming CPU unnecessarily. The only visible side effect is that the activity LED stops blinking in many situations because it no longer needs to indicate those SD card reader checks.
This trick is especially useful if you use your Raspberry Pi 3 or 4 as server with SSD or USB drivebecause it reduces overall wear and tear and avoids wasting CPU cycle time on something that doesn't contribute to your project.
Ten ways to use Raspberry Pi to save money
Beyond the hardware and fine-tuning, it's important to remember that a well-designed Raspberry Pi can be very helpful to reduce expenses on commercial services and devicesWith a few applications and a little time, it's possible to replace subscriptions, hosting, and third-party solutions that add up month after month.
A classic project is to convert the Raspberry Pi into media server With Plex, Kodi, or similar options, you can play your own movies and TV shows on your TV without relying on multiple paid streaming platforms. Obviously, it doesn't replace the entire Netflix catalog or similar services, but it does allow you to make the most of the content you already own and even share it across multiple devices in your home.
Another very powerful idea is to set up your own personal cloud with NextcloudInstead of paying for storage with Google Drive, OneDrive, or Dropbox, you install Nextcloud on your Raspberry Pi, connect an external drive, and have file, calendar, and contact synchronization, as well as collaborative editing, all under your control. For a family or small team, it's an excellent way to save on subscriptions.
If you want to strengthen your privacy without spending money on a monthly service, you can use the Raspberry Pi as VPN serverTools like WireGuard or OpenVPN, which you can configure on the Raspberry Pi, allow you to encrypt your traffic and access your home network remotely without needing a paid VPN service. Furthermore, since you're using your home network, you're not subject to third-party policies.
In the field of home automation, with Home Assistant installed on the Pi you can centralize control of plugs, lights, sensors, climate control, etc. Beyond convenience, this allows you to program automatic shutdowns, regulate temperatures and optimize energy use, which is directly reflected in your electricity and gas bill.
If you're interested in measuring exactly where your energy is going, you can set up a electricity consumption monitor with openHAB or other automation platforms. With the right sensors, the Pi collects real-time consumption data by circuit or device, helping you make informed decisions: detecting phantom devices, adjusting operating schedules, or improving insulation based on usage patterns.
You can also use the power of the Pi to automate your financial managementA small custom development (or using existing tools) allows you to build a 24/7 expense and budget control system that records transactions, generates reports, and alerts you when you approach certain limits. It's not so much a direct hardware saving, but rather a saving of time and avoiding poor decisions.
If you have an online project, instead of paying for traditional hosting for testing or lightweight websites, the Raspberry Pi can function as affordable web server For personal websites, portfolios, blogs, and development environments. For low to moderate traffic, it's a fairly efficient way to cut fixed costs.
Finally, a Pi can play the role of video surveillance system Low cost. Combined with IP cameras and specific software, it becomes the brain that records and manages the cameras in your home or small business. This eliminates the need to hire closed security solutions or more expensive NVR systems.
How much does it cost to keep a Raspberry Pi powered on all year round?
To find out if you're really overspending on your Raspberry Pi, it's worth doing numbers regarding their electricity consumptionA Pi 4, for example, does not behave like a light bulb that always consumes the same amount of power: depending on the load, different parts of the SoC turn on and off, just as you do not use the same amount of energy watching a movie on the sofa as running a marathon.
Measurements taken by specialist sources show that the Raspberry Pi 4, powered by an official 5,1V USB-C adapter, draws currents in this approximate range:
- At idle (standby, system on but without heavy load): around 575 mA.
- Loading a lightweight desktop environment like LXDE: around 885 mA.
- Playing 1080p video: about 600 mA.
- Recording 1080p video: around 640 mA.
With that data and the voltage of 5,1 V, we can convert to power (W) by multiplying current by voltage. You will get figures of around 2,9 W in standby and some 4,5 W under moderate loadIn practice, the average consumption is between 3 and 5 W, depending on what the Pi is doing, not counting USB peripherals that are powered by it.
The power supply also counts
One detail that many people forget is that the The power supply is not perfect.It also consumes energy to operate. Modern sources with efficiency certifications (such as the US Level VI standard) are usually quite good, but they still have losses.
In the case of the official Raspberry Pi USB-C power supply, it is said to consume... around 0,075-0,1 W when plugged in but not carrying anythingFurthermore, its conversion efficiency varies depending on the load: it can be, for example, around 70-80% depending on the power it is delivering to the Pi.
Taking into account that minimum efficiency, the power real taken from the wall It's not just the 2,9-4,5 W that the Pi dissipates, but something more. Calculations indicate approximate values ​​such as:
- Around 4,2 W at the outlet when the Pi 4 is at rest.
- Around 6,2 W at the outlet when it's loading LXDE or working a little longer.
These numbers already include power supply losses, but not other USB-connected devices (hard drives, SSDs, etc.), which would have to be added separately.
From watts to kWh and euros per year
Knowing the average power consumption of your Raspberry Pi allows you to extrapolate the annual consumptionA day has 24 hours and a typical year has 365 days. Kilowatt-hours (kWh) are obtained by multiplying the power (in kW) by the hours of use.
Taking the previous values ​​as a reference, if a Pi 4 were switched on 24/7 all year round We could estimate:
- Around 36-37 kWh per year if it is mostly kept at rest.
- Around 54-55 kWh per year with moderate usage similar to charging LXDE.
- Less than 1 kWh per year if only the power supply plugged in without the Pi, given its consumption of 0,075-0,1 W when unloaded.
If we apply a relatively high electricity price to these consumption levels (for example, something similar to €0,30-0,33/kWh), we obtain indicative annual costs such as:
- Around €12 per year for a Pi 4 running in standby mode 24/7.
- About €18 per year for a Pi 4 under continuous moderate load.
- Of the order of €0,20-0,30 per year if you only leave the power supply plugged in without the Pi.
In other words, in the worst-case scenario we're talking about less than €20 per year for having a Raspberry Pi 4 running all the time. The amount is small compared to what it can cost to keep a traditional PC running day and night.
Compare Raspberry Pi to a classic x86 server
To get an idea of ​​the real savings, it's helpful to compare a Pi 4 with a desktop or laptop computer converted into a serverAlthough it is a low-power device, it can easily draw around 60W on average from the power outlet, ten times more than the Pi in our example.
If an efficient x86 system consumed an average of 62 W throughout the year, that would amount to approximately 543 kWh annually. At relatively high electricity prices, this translates to something like €170-180 per year for energy alone for that server.
Compared to the Approximately €18 for the Pi 4 At moderate loads, the difference is around €160 per year. That means you could easily recoup the cost of acquiring one in just one year. Raspberry Pi 4 complete kit and continue saving each subsequent year.
Even if we take low-power x86 platforms like certain Intel Atom SoCs, with idle power consumption of 10-15W, as a reference, they are still two or three times more powerful than the Pi. For 24/7 use, that difference ends up being significant.
The importance of a good power supply
One point that is often overlooked but has an impact on both consumption and stability is the power supply qualityNot all power supplies that advertise "2,5 A" or "3 A" actually deliver what they promise, and if they don't supply the amperage or voltage stably, the Pi may automatically reduce the processor frequency or display the power failure icon.
Practical experience shows that many small, inexpensive power supplies deliver less current than advertised. Replacing them with high-quality power supplies, with current margin (e.g., 5 A) and good weight (More electronics, better build quality) makes a noticeable difference in smoothness, the absence of crashes, and the reduction of undervoltage messages. If you have several devices connected via USB, a camera, and a monitor, it's especially important to invest a little more here.
In short, a well-powered and properly sized Raspberry Pi for its task not only It consumes little power and saves money compared to a classic PC.But it also offers a much more stable experience. With the right settings—choosing the correct model, disabling unnecessary interfaces, managing storage, and understanding its actual power consumption—it's possible to build highly versatile projects without blowing your budget or your electricity bill.
