The Kiwitub burner also heats swimming pools, paddling pools, spa pools, water tanks, and lots of other things
It's really simple. All you need are two holes drilled or cut in the side, then screw in by hand a couple of standard 50mm plumbing plastic tank fittings. The standard Kiwitub hoses screw into these and you're away. There are detailed directions in the Kiwitub manual. We can also provide the fittings plus longer hoses if you need them.
The burner has been hooked up to plastic water tanks and barrels, cedar hot tubs, an old kauri beer vat, cast iron baths, lots of failed spa pools (they do that), and an inflatable paddling pool from The Warehouse. The paddling pool was 2.4m (8 feet) in diameter and not insulated like the Kiwitub , so it didn't get hotter than 36°C, but the kids thought it was fantastic. It took about 5 minutes to cut the holes and screw in the fittings, and many hours to get the kids out once they were in.
We've had dairy farmers hook the burner to small tanks to heat water to then mix milk powder with for calf rearing. If you're feeding the animals cold milk then the energy they're using to heat it up inside themselves isn't going into them growing. We've one farmer who's using the European technique of suspending a cow with nerve damage after calving in warm water - takes the pressure off and gives things a chance to heal.
The figures stack up extremely well for using the burner to heat a swimming pool. Place the burner beside the pool, connect the pool water hose to the burner inlet and another hose from the burner outlet spilling back into the pool. The water picks up heat as it runs through the burner and back into the swimming pool. And it's a lot of heat.
A swimming pool isn't as well insulated as the Kiwitub , but you want to lift the water temperature only a bit (not to bath temperature) and pumping the water through makes it more efficient again. We think you get to extend the season of your pool a couple of months either side of summer for the cost of a few bottles of gas. We're still waiting on feedback on this, but basically if you buy a Kiwitub to set beside the swimming pool, you also get a 36kW/hr. pool heater into the bargain.