A portable air heating system (PAHS) (1, 10, 34, 110, 134, 203, 210, 211, 300, 301), comprising: - a PAHS air inlet (2, 302); - a burner (3, 24, 40, 140, 303) connected to said air inlet, said burner comprising a fuel inlet for introducing fuel to said burner, a combustion blower for blowing air from an air inlet into said burner, thereby allowing for combustion of said fuel, and a burner air outlet for releasing heated air; - a first heat exchanger (5, 15, 36, 115, 136, 305, 358) for producing electricity, wherein said first heat exchanger is a thermoelectric power generator comprising thermoelectric modules, wherein heat is exchanged between said heated air and elements of said first heat exchanger; wherein said first heat exchanger comprises a first heat exchanger air inlet tube for heated air, said first heat exchanger air inlet tube connected to said burner air outlet, a first heat exchanger air outlet tube and a first heat exchanger body; wherein said first heat exchanger body is located around said burner air outlet or around said first heat exchanger air inlet tube; wherein said first heat exchanger body comprises air cooled elements, heat elements; and said thermoelectric modules located in between and in contact with said air cooled elements and said heat elements, thereby producing electricity when in operation; and wherein said heat elements and said air cooled elements have a first portion (54, 55) in contact with at least one of said thermoelectric modules wherein a surface of said first portion (55, 54) in contact with said at least one of said thermoelectric modules has an inclination in the range between 1 and 45 degrees in respect to a surface of a second portion (56, 57) of said heat elements and of said air cooled elements; and wherein said first heat exchanger consists of assembled single rings of built and assembled components, wherein each component comprises at least said air cooled element, said heat element and said thermoelectric square modules located in between and in contact with said air cooled element and said heat element; - a second heat exchanger (6, 16, 37, 58, 116, 137) for increasing the temperature of air entering said PAHS air inlet; and; - means for blowing air from said PAHS air inlet towards said first heat exchanger; wherein said means for blowing air from said PAHS air inlet towards said first heat exchanger are means for blowing air from said PAHS air inlet towards said first heat exchanger and second heat exchanger. - a PAHS air inlet (2, 302); - a burner (3, 24, 40, 140, 303) connected to said air inlet, said burner comprising a fuel inlet for introducing fuel to said burner, a combustion blower for blowing air from an air inlet into said burner, thereby allowing for combustion of said fuel, and a burner air outlet for releasing heated air; - a first heat exchanger (5, 15, 36, 115, 136, 305, 358) for producing electricity, wherein said first heat exchanger is a thermoelectric power generator comprising thermoelectric modules, wherein heat is exchanged between said heated air and elements of said first heat exchanger; wherein said first heat exchanger comprises a first heat exchanger air inlet tube for heated air, said first heat exchanger air inlet tube connected to said burner air outlet, a first heat exchanger air outlet tube and a first heat exchanger body; wherein said first heat exchanger body is located around said burner air outlet or around said first heat exchanger air inlet tube; wherein said first heat exchanger body comprises air cooled elements, heat elements; and said thermoelectric modules located in between and in contact with said air cooled elements and said heat elements, thereby producing electricity when in operation; and wherein said heat elements and said air cooled elements have a first portion (54, 55) in contact with at least one of said thermoelectric modules wherein a surface of said first portion (55, 54) in contact with said at least one of said thermoelectric modules has an inclination in the range between 1 and 45 degrees in respect to a surface of a second portion (56, 57) of said heat elements and of said air cooled elements; and wherein said first heat exchanger consists of assembled single rings of built and assembled components, wherein each component comprises at least said air cooled element, said heat element and said thermoelectric square modules located in between and in contact with said air cooled element and said heat element; - a second heat exchanger (6, 16, 37, 58, 116, 137) for increasing the temperature of air entering said PAHS air inlet; and; - means for blowing air from said PAHS air inlet towards said first heat exchanger; wherein said means for blowing air from said PAHS air inlet towards said first heat exchanger are means for blowing air from said PAHS air inlet towards said first heat exchanger and second heat exchanger.