The ornamental design for a sheetheatingelement for toilet seats, as shown and described.
FIG. 1 is a top plan view of the sheet heating element for toilet seats, according to the design;
FIG. 2 is a bottom plan view of the sheet heating element for toilet seats according to the design;
FIG. 3 is a left side elevation view of the sheet heating element for toilet seats illustrated in FIG. 1, with the right side elevation view being identical;
FIG. 4 is a front elevation view of the sheet heating element for toilet seats according to the design; and,
FIG. 5 is a rear elevation view of the sheet heating element for toilet seats according to the design.
The broken lines in the drawings represent portions of the sheet heating element for toilet seats that form no part of the claimed design.