When I was married and living in the houseboat, we had a stacked washer dryer which was really just one unit. Each had a very small capacity, but it fit in our houseboat which was the main criterion. The dryer used 120volts, which if you know anything about dryers is half the voltage of standard electric dryers. At half the power, the dryer took twice the time.
I suppose that this unit was designed for a household of one or two that did little laundry. However, my husband was a construction worker and we had a new baby. Thus we had lots of laundry, including very dirty work clothes and many many diapers. Now it was certainly better to be able to do the laundry at home than having to drive a with a new baby to a laundromat, but it meant that the washer/dryer was running most of the time. Since I was home with a new baby, this meant I was able to do wash all day, which is what it seemed like at the time.
If I had known what awaited me in our first home on the land, I would have treasured even this all-in-one. At least this machine filled and drained itself, had a rinse cycle and dried clothes.