Sun-Mar and similar venting heat loss

I'm building a house within the city limits of Bloomington, Indiana and so have to follow all of their codes, which outlaw the simple bucket composting toilet methods and require a sewer/septic hookup to every house. I'm working on getting around this requirement by trying to convince them of the 'approved' composting toilets like the ones made by Sun-Mar. They are much more expensive and fancy than we need or want, but if it means they'll let us avoid the cost of sewer/septic, it actually works out as a gain ... oh the frustration of building in a city.

Anyway, does anyone have experience with these and their venting systems? It appears that there is a fan running 24/7 sucking air through the toilet outside, which would be a huge waste of heat in the winter (we're trying to get as close to 100% passive solar as possible). Is this true? If so, is there a way to avoid all of that heat loss? Perhaps there are other 'official' composting toilets that don't have this 24/7 fan requirement?

Consider the whole house basement system. With the lo-flow toilets. Most of the systems require a draft on the
exhaust. If it can be done naturally, best. If it requires a small DC fan, it can be run from a small photovoltaic
cell.
The low-flow system looks "normal" and may be acceptable to the "authoritaaa".

Don't give up, keep trying, you may just wear them out.

Hey Zach,

I wonder how things are going? Are they letting you go ahead with your plans?

SunMar also makes non-electric models, such as the Excel NE, which use a larger vent pipe, and there is no heater. On their "regular" Excel model, if you don't need to use the heating element, you can dis-connect it to save on electricity. The heating pad -- for anyone reading along -- is useful for colder locations or weekend cabins that are not heated all the time. Since the composting essentially stops at around 50F, the goal is to keep it at least that warm, and certainly to prevent it from freezing. The heater uses a lot of juice over the course of a winter (especially for an off-grid home!), so if the unit is in a heated space either disconnect it, or play with the thermostat to get it to only come on when really needed. You may need to replace the thermostat with one that gives you better control. If the drum freezes, the gears and crank can break if you try to rotate the drum, and it takes quite a while to thaw out.

For those struggling with the electric load of a vented unit and would like to save on the electric fan loads, they now make a retro-fit kit to convert an Excel into an Excel NE. Costs about $150 US.

The larger, tank-beneith-the-floor units from SunMar are the Centrex toilets. They cost more, but they take up a LOT less floor space, are MUCH more comfortable to sit on, look much more like a regular flush toilet, and are probably more durable. I agree with Joe that these would have a better chance of approval, and if you must use a flush model, they do make a very low-volume unit. The problem then becomes using the power vent to remove all that extra moisture...

If you have a cold location, and you are allowed by local codes to have an outdoor "humanure" compost bin, but don't want (or would not be allowed to have) a Jenkins' sawdust bucket toilet, look into Nature's Head. These are great little urine-separating toilets that cost about 1/2 as much as the SunMar line.

As a matter f full disclosure, I own a renewable energy business and sell both SunMar and Nature's Head, though I like the Nature's Head toilets a lot more. I am not attempting to sell anything here -- just to offer helpful information. I use a bucket toilet at home a la Joseph Jenkins and The Humanure Handbook. We built a new straw bale home and installed the plumbing for a toilet drain, but we don't use or have a flush toilet in the home -- our Loveable Loo sits right above the capped drain pipe.

I've got a SunMar Spacesaver I picked up for $300.00. Very good condition and clean. The back heater cover was broken though. I don't want to use the heater anyway as I live off-grid.  I live in tropical location so never cold.  Does anyone know, can you use the conversion kit on the space saver to basically make a NE?  Has anyone done it? I'm having a plumber friend put it in and when I looked at the parts, I was wondering if these could just be picked up at hardware or plumbing store. I would go with Natures Head but I already have this and would like to try and use it. Any ideas appreciated.