EZvac

EZvac is a standalone HVAC and indoor-climate simulation plugin for Paper 26.1 to 26.3 and its forks, including Purpur. It still runs on 1.21.x until BETA 2.x. Build heat pumps, air conditioners and furnaces out of dispensers, link vents to a room, and a sign thermostat keeps it at the temperature you set, while the outdoors follows the time of day, the biome and the weather.

• Systems for rooms (iron trapdoor vents) or pools (copper grate vents), with variable-speed equipment, operating profiles and an ETA on the thermostat sign.
• Climate: a realistic climate for every biome, seasons, colder air up mountains and steady air deep underground, weather, daily wind, humidity, a "feels like" temperature, smooth transitions between biomes, and readings that vary a little from spot to spot.
• Dehumidifiers and humidifiers that dry or moisten a room or a shed.
• Air quality: smoke, dust and pollen in every room, scored as the real Air Quality Index, and air purifiers whose coral filters fill up.
• Sensors: thermometers, hygrometers, air monitors, and button sensors that report to a sensor hub sign.
• Lit screens on every sign and click-to-open control menus for setpoints.
• An on-screen HUD and PlaceholderAPI placeholders.
• Fahrenheit or Celsius, server wide, and configurable sounds. No fuel, power or items needed.

Release status: EZvac BETA 1.0 Pilot 1 is the first BETA. It runs on Minecraft 26.1 to 26.3 (Paper or Purpur), and still on 1.21.x until BETA 2.x. Every screen is redesigned as a status strip coloured by what the device is doing. The pale garden, the dappled forest and the sulfur caves get their own climate and air, and admins are told when a newer EZvac is out. /hvac quicksettings gives owners one menu to switch device kinds, air quality, pollen, wind and the seasons on or off, and to back the registry up. Heating and cooling can go by building size: one three-star unit per 1,860 blocks of air, so big builds need more equipment. It's on for new servers and starts off on upgraded ones. Weather stations forecast the next seven days for players nearby (/hvac forecast). Your save carries over unchanged.

ALPHA 3.2 added air quality. Every room tracks fine particles, dust and pollen, scored as the US EPA Air Quality Index: campfires and fire make smoke, deserts and the Nether bring dust and ash, and spring brings pollen. Air purifiers clean it, and their tube coral filters fill and die. Every day also has its own wind, from Calm to a Gale: it chills the outdoors, makes houses leakier, and raises dust storms in the desert. ALPHA 3.1 added equipment tiers, shown as stars: ★☆☆ single-stage, ★★☆ two-stage and ★★★ variable-speed. ALPHA 3.0, Linked systems, dropped group names. You link equipment, vents and signs to a thermostat with one link tool, thermostat names can repeat, and a system that loses its thermostat waits, headless, for a new one. Upgrading from 2.x converts hvac.yml to a new format and keeps the old file as a backup; there's no going back to 2.x without it. ALPHA 2.2 let addons see every device. ALPHA 2.1, Realism: EXTENDED, gave every biome its own climate, with smooth transitions between them, seasons on EZvac's own calendar, colder air up high and steady air underground, lit screens and control menus on every sign, and Fahrenheit or Celsius server wide. See the changelog.

BETA 1.0 pilots: pilots are test builds of BETA 1.0, published as prereleases (betas on Modrinth) before the full release. A server running a pilot is told about newer pilots; one running a full release only about full releases.

1.21.x is on its way out. BETA 1.x still supports Minecraft 1.21.1 to 1.21.11 and says so at start-up. It's played and tested on 26.x first: on 1.21.x each release passes the automated tests on a few versions (1.21.1, 1.21.4, 1.21.5, 1.21.8 and 1.21.11), but nobody plays on it for testing. BETA 2.x will drop 1.21.x entirely: it needs Minecraft 26.1 or newer. Update your server before then; see Upgrading.

Quick install

1. Download EzVac-BETA-1.0-P1.jar from the releases or Modrinth.
2. Put it in your server's plugins folder. You need Paper 26.1 to 26.3 or a fork such as Purpur, on Java 25. 1.21.x on Java 21 still works until BETA 2.x.
3. Start the server, then follow Getting started to build your first system.

Documentation

Page	What's in it
Getting started	Install, then a first working system step by step
Equipment and thermostats	Thermostats, every kind of equipment and its casing, profiles, RPM monitors
Vents and airflow	Linking vents, how far air reaches, pools
Dehumidifiers and humidifiers	Building and using them, "Air too cold"
Air quality and air purifiers	The AQI, pollen, smoke and dust, and purifiers with coral filters
Sensors and readings	Thermometers, hygrometers, sensors and sensor hubs
Weather stations	A tower that forecasts the next seven days; /hvac forecast
Screens and control menus	The screens on every sign, the setpoint menus, and quick settings
Climate	Outdoor temperature, weather, humidity, feels-like, variance
Wind	Each day's wind, where it blows, and what it does

The full technical behaviour is in docs/features.txt, and every release's changes in the changelog.

Extending EZvac

Addons are ordinary Paper plugins that use EZvac's public API: climate readings for any spot or player, thermostats, the seasons, and events. Add com.github.EZvac-Plugin.EZvac:ezvac-api from JitPack and see The EZvac API.

Building from source

You need Java 21 or newer and Maven 3.9 or newer. EZvac builds against the Paper 1.21.1 API, so one jar runs on 1.21.1 and on 26.1 to 26.3.

mvn clean package

The plugin is written to ezvac-plugin/target/EzVac-BETA-1.0-P1.jar. mvn verify also runs the test suite, as GitHub Actions does on every push and pull request. See CONTRIBUTING.md.

License

EZvac is released under the MIT License, starting with ALPHA 1.5. Copyright (c) 2026 bladestech and EZvac contributors.

Releases through ALPHA 1.1 HOTFIX were dedicated to the public domain under The Unlicense. That dedication is irrevocable: those versions remain public domain and may still be used on those terms. The MIT License applies to ALPHA 1.5 and everything after it.

Contributions are accepted under the same MIT terms — see CONTRIBUTING.md.