Thrive Homes has developed and built its first four properties in Three Rivers.
Four families have already moved into the two-bedroom homes built by the housing association, which manages more than 4,000 rented homes in Hertfordshire and Buckinghamshire.
Two of the properties have been built in Gleneagles Close, in South Oxhey and the other two are in Clarkfield, in Mill End.
Both developments replaced bungalows which had to be demolished following fires.
Jo Barrett, operations director of Thrive Homes, said: "We identified a real need for this type of family home and saw this as a perfect opportunity to develop quality properties suitable for affordable rent."
She added: "We listened to local people when we put together the plans, and are delighted with the positive feedback we’ve had."