Many owners of HMOs, student houses and holiday lets are increasingly concerned about the rise in energy prices eroding their rental income. Fitting a coin meter or coin box to the tumble dryer and washing machine in the HMO is the answer to misuse of electricity by tenants. Fitting the Speeder SP100 coin box to the washing machine and tumble dryer gives the landlord control over energy usage. The combination of an SP100 and a domestic washing machine and tumble dryer gives the owner of a HMO a coin operated washing machine and a coin operated tumble dryer. The SP100  tumble dryer coin box or SP100 washing machine coin box provide a useful extra income for landlords of HMOs.