Product: HOMER Pro
HOMER Pro will adopt the currency symbol, decimal separator, and digit grouping symbol that is set in Windows.
You can set the Windows locale in the Control Panel. Go to "Time & Language".
Then choose your country or region from the drop-down menu at the top of the window.
Click on "Additional date, time, & regional settings" to customize specific settings. You only need to do this if you want formats other than the default for your location, for example if you have the format set to "English (United States)" but you want the Euro symbol to appear for currency. These instructions are for Windows 10, although the step will be similar for other versions of Windows. Your computer might require different steps than these -- if in doubt, refer to http://windows.microsoft.com/ for up-to-date official instructions.
You can change the currency from the default currency (taken from the system currency) in the Project > Economics menu. The economics menu is in the "System" tab of the menu bar (or you can access it through the small shortcut button "$" at the bottom of the schematic, which appears only when you have added one or more components to your model). At the bottom of the economics menu is a drop-down list of currencies -- you can change the currency for the model here. The currency will be saved with the model, and anyone else who opens this model will see the currency you've selected. You could, for example, create some of your models in U.S. dollars, and other models in euros, and the currency unit will be saved with the model.
Be careful when changing the currency of a .homer file. HOMER will never convert the currency values, and will use the same numeric values regardless of which currency symbol is chosen, so be sure to change all costs to reflect the new units. Component costs, fuel costs, fixed costs (economics tab of project settings), emissions penalties (emissions tab of project set-up), grid prices, grid control parameters (real time rates), electric load efficiency measures, and unmet hydrogen load penalty all contain currency-specific cost values. Some library components contain default cost data provided by the manufacturer (and our "generic" brand components contain cost suggestions) -- these numbers are in U.S. dollars.