On the weekend I bought 3m of 10mm diameter (1m thick) aluminum tube (about $7) and bent it to make a drying rack which fits under the vent on my home air conditioner. This allows me to dry washing while using the air conditioner as a heat pump. Perhaps air conditioner makers could offer this as an accessory.
Ideally washing should be dried in the sun naturally, without the need for a clothes dryer. But many homes are now equipped with a dryer. It may be difficult to convince the average householder to give up their dryer, so it might be better to give them a more efficient cheaper one.
Electric tumble dryers use an electric heating element which warms the air and then discharge hot wet air into the room or outside. This is very inefficient. Some more expensive "condensing" dryers use mains water to condense the humidity out of the discharge air. These waste water as well as electricity.
A cheap and simple alternative might be to equip the laundry with a reverse cycle air conditioner. The clothes would be hung on a small fixed rack above the laundry tub, under the air conditioner. Ideally the air conditioner would have an interlock so it would not operate when the door or window of the room is open.
Assuming the home is already being equipped with air conditioning, an extra outlet for the laundry should be cheaper than an electric clothes dryer. An alternative might be a fan and duct to circualte air from an air conditioner elsewhere to the drying room.