FHEM vs openHAB
A side-by-side comparison of two self-hosted home automation options — licensing, setup difficulty, resource needs, and what each one replaces.
FHEM
Perl-based server for home automation tasks
VS
openHAB
Vendor-neutral open-source home automation
| Feature | FHEM | openHAB |
|---|---|---|
| Deploy effort | Under-an-hour setup | Under-an-hour setup |
| Health score | 62 · Good | 79 · Good |
| Category | Home Automation | Home Automation |
| License | GPL-2.0 | EPL-2.0 |
| Language | Perl | Java |
| Setup difficulty | Hard | Hard |
| Min. RAM | 256 MB | 1,024 MB |
| Deployment | docker, bare-metal | docker, bare-metal |
| GitHub stars | ★ 22 | ★ 1,142 |
| First released | 2005 | 2010 |
| Replaces | SmartThings | SmartThings, Google Home |
What are FHEM and openHAB?
FHEM
FHEM is a long-standing, GPL-licensed server for home automation used to control lights, heating, alarms, and many other devices. It supports a vast range of protocols through community modules.
- Vast protocol support
- Community module library
- Lightweight Perl server
- Long-term reliability
openHAB
openHAB is a vendor-neutral, open-source home automation platform that integrates many devices and technologies behind one system. It targets smart home enthusiasts wanting deep configurability. It is deployed via Docker or native packages.
- Hundreds of device bindings
- Powerful rule engine
- Runs fully offline
- Cross-platform
FHEM vs openHAB: key differences
FHEM is written in Perl, while openHAB is built with Java. Licensing differs — GPL-2.0 for FHEM versus EPL-2.0 for openHAB. FHEM is the lighter option, starting around 256 MB of RAM against 1,024 MB for openHAB. FHEM is the more established project (first released 2005), while openHAB arrived in 2010. OpenHAB has the considerably larger community, at 1,142 GitHub stars versus 22.
Why pick each one
Choose FHEM if…
- Extremely mature
- Runs on modest hardware
Watch out for
- Dated, technical interface
- Configuration is arcane
Choose openHAB if…
- Very flexible
- Vendor neutral
- Mature project
Watch out for
- Steep learning curve
- Heavier Java runtime
Frequently asked questions
Is FHEM or openHAB better?
Neither is universally better. openHAB has the larger community; both share a hard setup difficulty, so the decision comes down to features and licensing.
Are FHEM and openHAB free and open-source?
Yes. FHEM is licensed under GPL-2.0 and openHAB under EPL-2.0. Both can be self-hosted at no software cost.
Can I run FHEM and openHAB with Docker?
FHEM: yes. openHAB: yes.
Which is lighter on resources, FHEM or openHAB?
FHEM has the smaller minimum footprint at 256 MB of RAM, compared to about 1,024 MB for openHAB. Real-world usage depends on library size, user count, and enabled features.