With regard to the invoice issued by the professional, only the purchase price or the cost of the equipment, materials or appliances, all taxes included, is taken into account.

The labor corresponding to the installation of this equipment is excluded from the basis of the tax credit.

Also excluded are administrative and financial costs (e.g. loan interest).

As an exception to this principle, the cost of labor can be included in the basis of the tax credit for thermal insulation work on opaque walls.