Does my property with electric heating cost too much to rent out?

With electric heating, every kWh goes directly on your bill, without buffer, and guests have no incentive to heat sparingly because they themselves don't pay anything extra. This means actual heating costs are often higher than what you've built into the rental price, especially with a high thermostat or an open window. This doesn't solve an insulation problem: with structurally high consumption due to poor insulation, that remains a cost item you need to address differently. However, you can let guests pay for their own consumption, so the costs of their choices no longer fall on you.