The design of a baseboardheater, as shown and described.
FIG. 1 is a perspective view from the front and above of a baseboard heater, according to the present design;
FIG. 2 is a perspective view from the back and above therof;
FIG. 3 is a top view thereof;
FIG. 4 is a left elevational view thereof;
FIG. 5 is a front elevational view thereof;
FIG. 6 is a right elevational view thereof; and,
FIG. 7 is a rear elevational view thereof.
The baseboard heater is shown broken to indicate that a specific length forms no part of the claimed design.
The broken line showing of parts of the drawings is included for the purpose of illustrating use and environment and forms no part of the claimed design.