It's now over a year since we replaced our old cassette toilet with the Airhead composting toilet. So how have we got on? Was it worth it? Might we consider going back to the cassette loo which is still stored in our shed at home just in case? This might get a tad explicit for some so those of a delicate disposition might like to go off to read someone else's blog at this point! Hold your nose and here we go.
Well it's been an interesting year. It certainly didn't start too well because the original Airhead installation wasn't airtight enough and leaked the "exhaust" gases back into the boat. Most unpleasant. The trick is to ensure that the exhaust fan housing is properly sealed where it fixes to the side ( or ceiling in some cases) of the cabin. We eventually got that right (thanks Rick) by gluing a thick board to the wall to give the fan housing retaining screws something strong to bite into. That and plenty of sealant.
The toilet itself operates well, easily keeping solids and liquids separate, and because the fan draws air inwards into the toilet and out through the exhaust, the toilet waste tank itself is remarkably odour free even when the lid is open. Considerably more odour free than a cassette toilet. It is easy to keep clean and is I think pretty hygienic.
The daily emptying of the liquid tank is easy and quick. It's a lot more portable than a cassette. If there is a sanitary station nearby we use that, if not, we tip it on waste land, not into the canal.
We've only had to empty the solids tank three or four times. When I say "we" I actually mean Kath, bless her.. She says that whilst it is not fair to describe it as pleasant, neither is it dreadful and she much prefers it to regular emptying of cassettes. We bag up the waste in plastic coal bags which can be safely deposited in a rubbish skip.
We've been on a learning curve as regards the addition of a composting medium. This does seem to make a difference to the frequency of wafts of whiffs emerging from the exhaust port on the outside of the boat. This has on occasions caused us to worry that we were a little unpleasant to be near in confined spaces like locks despite being odour free inside the boat. After talking to other Airhead users, notably Adam and Adrian on Briar Rose, (more thanks) we are now using coco fibre ( compressed powdered coir from pet food shops). There needs to be sufficient so that the daily turning of the stirring handle stirs the "donations" into the coir. This seems to work well and now occasional nasty niffs outside the boat are largely avoided.
The final thing to mention is the electric fan itself. Although it draws only a tiny current it could drain the boats batteries over a few weeks if the boat were left unattended over the winter. For most of the year our solar panel takes care of this, but in December and January when daylight is short and low it doesn't. I decided to switch off the fan over this period, but this created another problem. After a period at rest in the cold and damp, the fan was reluctant to start again when switched back on. I solved this by spraying WD40 in through the exhaust hole outside the boat and giving the fan blades a flick with a stick poked in the same hole. I think next winter I may leave the fan on and just visit the boat now and then to recharge the batteries, or I could leave Herbie plugged into the shore power, although I would be reluctant to do this unless I get a galvanic isolator to prevent hull corrosion.
So what is our conclusion? Despite a few problems, most of which we have overcome now, we much prefer the Airhead to our previous cassette toilet. It is probably more hygienic, considerably more pleasant to use, uses no chemicals, and removes the need to seek out sanitary stations every few days, and of course, compared with a pump out loo, it costs nothing to empty.
Every boater has views on toilets, and these are just our views. Other makes of composting toilet are available.