Carel said they had been fully booked since they opened and were now taking bookings for 2017.
The couple from Holland had moved to New Zealand 35 years ago, he said.
"We looked at a map and decided to get as far away from Holland and Europe as possible.
"When we arrived in New Zealand, such a beautiful country, we were in awe - especially as we first lived at Mt Cook. I was a cleaner and Elspeth was a housemaid."
Carel said they feel that they are just caretakers of their land.
"We want to leave it behind in the best possible condition."
Their purpose-built luxury lodge, with four large luxury rooms as well the couple's home, is not only the highest rated accommodation in the Ruapehu district it is a global award winner.
Last week they were awarded the 2016 Green Leaders Trip Adviser Platinum award, a major global award.
"We are, of course, very, very proud."
And the lodge has also been touted locally as the top five-star accommodation in the Ruapehu district.
Every room has a spectacular view of Mt Ruapehu.
"So this is a very special place, looking out on to a very beautiful mountain."
Being completely sustainable means at the lodge they collect all their own water, which is extensively filtered, they are 100 per cent solar powered and even export electricity to the grid because they produce so much, he said.
Recycling is prime and every guest room has a recycle compost bin for food scraps, he said.
They have even installed their own sewerage system.
"It has been hard work, but we had our vision and it makes us very happy that everyone who has stayed here loves it and they send us messages to tell us."