Layer 5 · self-hosting reality check
What it actually takes to self-host openHAB
The docs say 1 GB. In practice you want 2 GB — the JVM is the floor. Here is the honest version — real requirements, real monthly cost, what you will be maintaining, and the one thing that catches people out.
Usually reached from Proprietary Smart-Home Hubs alternatives, where openHAB is one of the picks.
| RAM — documented minimum | 1 GB |
|---|---|
| RAM — what it really needs | 2 GB — the JVM is the floor |
| CPU | 2 vCPU |
| Disk | 16 GB |
| Monthly cost | $0 on hardware you own |
| Setup time | 3 hours; the concepts take longer than the install |
| How you install it | openHABian on a Pi, or a JVM deployment anywhere |
| Ongoing maintenance | Moderate. Major versions have historically required configuration migration. |
| Where it stops scaling | Large installations; the rules engine is genuinely powerful once learned. |
The thing that catches people out
openHAB's Things, Channels and Items model is powerful and it is a genuine conceptual barrier — you cannot skip learning it, because nothing works until the mapping is right. People coming from Home Assistant expect devices to appear and be usable; here they appear as Things that must be linked to Items before anything can use them. Budget an evening for the model, not the installation.
When not to self-host openHAB
You want the largest integration ecosystem and the fastest path to a working dashboard. Home Assistant is ahead on both.
Every guide here carries this section. A site that only ever tells you to self-host is selling something — the useful answer is sometimes no.
Other Layer 5 self-hosting guides
- Self-hosting LibreOffice2 GB with a large spreadsheet open
- Self-hosting ONLYOFFICE6 GB for the Document Server with a handful of concurrent editors
- Self-hosting Collabora Online4 GB, and roughly 1 GB per 20 concurrent documents
- Self-hosting CryptPad2 GB for a small instance
- Self-hosting Mattermost4 GB for a team of 50 with PostgreSQL on the same box
- Self-hosting Rocket.Chat6 GB with MongoDB on the same machine
Common questions
- How much RAM does openHAB actually need?
- 2 GB — the JVM is the floor in practice. The documented minimum is 1 GB, which is the figure at which the process starts rather than the figure at which it works under real use. 2 vCPU alongside it.
- What does self-hosting openHAB cost per month?
- $0 on hardware you own This is commodity VPS pricing and excludes your time, which is the larger cost for most people — budget for moderate. Major versions have historically required configuration migration.
- How long does it take to set up openHAB?
- 3 hours; the concepts take longer than the install, via openHABian on a Pi, or a JVM deployment anywhere.
- When should I NOT self-host openHAB?
- You want the largest integration ecosystem and the fastest path to a working dashboard. Home Assistant is ahead on both.
- What is the most common mistake when self-hosting openHAB?
- openHAB's Things, Channels and Items model is powerful and it is a genuine conceptual barrier — you cannot skip learning it, because nothing works until the mapping is right. People coming from Home Assistant expect devices to appear and be usable; here they appear as Things that must be linked to Items before anything can use them. Budget an evening for the model, not the installation.