Greenhouse arrangement comprising - a framework and - a system for thermicity improvement, which comprises at least one - film spread over and/or connected directly and/or indirectly to the framework - comprising an additive suitable for enhancing the thermicity of the film, wherein said additive comprises an alkyl phosphonic acid or derivatives thereof, - wherein said alkyl phosphonic acid is chosen from - a methane phosphonic acid, - ethane phosphonic acid, - propane phosphonic acid or - wherein said alkyl phosphonic acid is - an ammonium salt of an alkyl phosphonic acid, and /or is - a phosphonic esther of an alkyl phosphonic acid or - wherein said alkyl phosphonic acid is chosen from - dimethylspirophosphonate, - ethylene diamine methane phosphonate, - melamine methane phosphonate, - wherein said film has a transmission of IR of lower than 40%, especially lower than 25%. - a framework and - a system for thermicity improvement, which comprises at least one - film spread over and/or connected directly and/or indirectly to the framework - comprising an additive suitable for enhancing the thermicity of the film, wherein said additive comprises an alkyl phosphonic acid or derivatives thereof, - wherein said alkyl phosphonic acid is chosen from - a methane phosphonic acid, - ethane phosphonic acid, - propane phosphonic acid or - wherein said alkyl phosphonic acid is - an ammonium salt of an alkyl phosphonic acid, and /or is - a phosphonic esther of an alkyl phosphonic acid or - wherein said alkyl phosphonic acid is chosen from - dimethylspirophosphonate, - ethylene diamine methane phosphonate, - melamine methane phosphonate, - wherein said film has a transmission of IR of lower than 40%, especially lower than 25%. - film spread over and/or connected directly and/or indirectly to the framework - comprising an additive suitable for enhancing the thermicity of the film, wherein said additive comprises an alkyl phosphonic acid or derivatives thereof, - wherein said alkyl phosphonic acid is chosen from - a methane phosphonic acid, - ethane phosphonic acid, - propane phosphonic acid or - wherein said alkyl phosphonic acid is - an ammonium salt of an alkyl phosphonic acid, and /or is - a phosphonic esther of an alkyl phosphonic acid or - wherein said alkyl phosphonic acid is chosen from - dimethylspirophosphonate, - ethylene diamine methane phosphonate, - melamine methane phosphonate, - wherein said film has a transmission of IR of lower than 40%, especially lower than 25%. - comprising an additive suitable for enhancing the thermicity of the film, wherein said additive comprises an alkyl phosphonic acid or derivatives thereof, - wherein said alkyl phosphonic acid is chosen from - a methane phosphonic acid, - ethane phosphonic acid, - propane phosphonic acid or - wherein said alkyl phosphonic acid is - an ammonium salt of an alkyl phosphonic acid, and /or is - a phosphonic esther of an alkyl phosphonic acid or - wherein said alkyl phosphonic acid is chosen from - dimethylspirophosphonate, - ethylene diamine methane phosphonate, - melamine methane phosphonate, - wherein said alkyl phosphonic acid is chosen from - a methane phosphonic acid, - ethane phosphonic acid, - propane phosphonic acid or - a methane phosphonic acid, - ethane phosphonic acid, - propane phosphonic acid or - wherein said alkyl phosphonic acid is - an ammonium salt of an alkyl phosphonic acid, and /or is - a phosphonic esther of an alkyl phosphonic acid or - an ammonium salt of an alkyl phosphonic acid, and /or is - a phosphonic esther of an alkyl phosphonic acid or - wherein said alkyl phosphonic acid is chosen from - dimethylspirophosphonate, - ethylene diamine methane phosphonate, - melamine methane phosphonate, - dimethylspirophosphonate, - ethylene diamine methane phosphonate, - melamine methane phosphonate, - wherein said film has a transmission of IR of lower than 40%, especially lower than 25%.