The most direct fix to your line of code is:

subprocess.call(['C:\EnergyPlusV8-5-0\energyplus.exe', '-w', 'path/to/weather.epw', 'PackagedTerminalHeatPump.idf'])

The EnergyPlus executable always comes first in the list of arguments passed to subprocess.call (or check_call or Popen), and the IDF comes last. For the other options, you specify the option, then its argument (where required).

Here is the CLI help which you may find useful in building up your command.

EnergyPlus, Version 8.5.0-c87e61b44b
Usage: energyplus [options] [input-file]
Options:
  -a, --annual                 Force annual simulation
  -d, --output-directory ARG   Output directory path (default: current
                               directory)
  -D, --design-day             Force design-day-only simulation
  -h, --help                   Display help information
  -i, --idd ARG                Input data dictionary path (default: Energy+.idd
                               in executable directory)
  -m, --epmacro                Run EPMacro prior to simulation
  -p, --output-prefix ARG      Prefix for output file names (default: eplus)
  -r, --readvars               Run ReadVarsESO after simulation
  -s, --output-suffix ARG      Suffix style for output file names (default: L)
                                  L: Legacy (e.g., eplustbl.csv)
                                  C: Capital (e.g., eplusTable.csv)
                                  D: Dash (e.g., eplus-table.csv)
  -v, --version                Display version information
  -w, --weather ARG            Weather file path (default: in.epw in current
                               directory)
  -x, --expandobjects          Run ExpandObjects prior to simulation
Example: energyplus -w weather.epw -r input.idf

I've wrapped this up in a little module you can find here. So long as EnergyPlus is installed in the usual place for your system and the install directory is on your path then this ought to work straight out of the box.

Using Popen with multiple args and piping the output to display the actual error message

Since subprocess.check_call shouldn't have stdout and stderr pipes, you should use Popeninstead.

See the subprocess documentation especially check_call and for Popen.

import subprocess

eplus_path = '/Applications/EnergyPlus-8-6-0/energyplus'
eplus_file = '5ZoneAirCooled.idf'
weather_file = 'USA_CO_Golden-NREL.724666_TMY3.epw'

df = subprocess.Popen([eplus_path, "-w", weather_file, eplus_file], stdout=subprocess.PIPE)        
output, err = df.communicate()
print(output.decode('utf-8'))
if not err is None:
    print(err.decode('utf-8'))

In a case where it goes well, I'll see something that starts with:

EnergyPlus Starting
EnergyPlus, Version 8.6.0-198c6a3cff, YMD=2017.01.17 23:46
Processing Data Dictionary
Processing Input File
... etc

In a case where for example I don't have the right idf file in my folder:

ERROR: Could not find input data file: /Users/julien/Software/RunningEPlusFromPython/2ZoneAirCooled.idf.
Type 'energyplus --help' for usage.

Shlex as helper to parse a command

Note that the subprocess calls expects a list of arguments. Using shlex to decompose a command line (that you can try directly in a terminal/cmd prompt) can be useful:

In [1]:
import shlex
command_line = '{eplus_path} -w {weather_file} {eplus_file}'.format(eplus_path= eplus_path, weather_file=weather_file, eplus_file=eplus_file)
print(command_line)

Out [1]:
/Applications/EnergyPlus-8-6-0/energyplus -w USA_CO_Golden-NREL.724666_TMY3.epw 5ZoneAirCooled.idf

In [2]: shlex.split(command_line)
Out[2]: ['/Applications/EnergyPlus-8-6-0/energyplus',
         '-w',
         'USA_CO_Golden-NREL.724666_TMY3.epw',
         '5ZoneAirCooled.idf']

Seeing the EnergyPlus simulation output in real time as the simulation runs

If you need to do this, here's how:

import subprocess
# If python 2.7: `from __future__ import print_function`

popen = subprocess.Popen([eplus_path, "-w", weather_file, eplus_file],
                         stdout=subprocess.PIPE, universal_newlines=True)

# Might need to use `#for stdout_line in iter(popen.stdout.readline, ""):` instead in python 2.7
for stdout_line in popen.stdout:
    print(stdout_line)

popen.stdout.close()
return_code = popen.wait()

if return_code:
    raise subprocess.CalledProcessError(return_code, popen.args)

Side note

From the docs on the energyplus CLI (command line interface), if you don't supply -w weather_file_path it searches for in.epw in the current directory (where it's called from). So a quick fix would be to make sure that your weather file is there an named in.epw. Just saying.

Hi, I tried this:

import subprocess

subprocess.call(['C:\EnergyPlusV8-6-0\energyplus.exe', '-w','C:\EnergyPlusV8-6-0\PRT_Lisboa.epw','C:\EnergyPlusV8-6-0\AdultEducationCenter.idf'])

but in the eplus.err says:

** Severe  ** HVACTemplate objects are found in the IDF File.
**  Fatal  ** Program Terminates: The ExpandObjects program has not been run or is not in your EnergyPlus.exe folder.

In fact, the ExpandObjects application file is there. Also, for other .idf files it asks for the in.idf and also doesnt run.

Do you know what to do?

Thank you very much for your time