I just stumbled across some information about the Normatherm KKH20 Passivhaus Boiler Stove and am curious if anyone in here is personally familiar with them. 

"The Normatherm KKH 20 stove which has a large square window in front of the fire, gives very little heat to the room at 1.9kW (6,483 Btu/h) and most of the heat to water at 17.3kW (59,030 Btu/h.) This means that you can run a Normatherm KKH 20 boiler stove in a low energy or Passvihaus and not totally overheat the room that the stove is in. Some small part of the heat may be needed for space heating for a few weeks of the year but most will be used for domestic hot water during the cooler months when the solar thermal input is that much lower. The Normatherm KKH 20 can be totally room sealed by connection to an external air duct and this air is thermostatically controlled to automatically regulate the output of the stove."

Additional technical information about this model can be found here.   Any idea whether or not they're available anywhere in North America or have any intentions of being? It's intriguing technology for a Passivhaus and completely Green.   I've already contacted the manufacturer (in Germany) but have yet to hear anything back from them.

Litawyn

Anybody?

There are a couple of U.S. made small wood fired boilers with viewing windows. I was looking at some last night. Wood gasification units with catalytic exhaust. They were pricey around $4,000. Don't know anything about these boilers. Most indoor boilers don't have a viewing window. The viewing window is a large part of what makes indoor fires so nice. I hope manufacturers come out with more models to choose from...I built my own indoor wood fired boiler with window for less than $800....though its not EPA certified....

The online stores you're perusing won't ship to the US and there is minimal import interest. This site imports a very nice German gasifier though:
http://www.hydro-to-heat-convertor.com

A second possibility is www.ebay.co.uk I bought this stove online: http://www.ebay.co.uk/itm/Aarrow-EB12-HE-Multifuel-Wood-Burning-Boiler-Stove-/260902063070?pt=UK_HG_FireplacesMantelpieces_RL&hash=item3cbef98bde#ht_1159wt_912

A couple of caveats. The Brit stoves require stuff that hasn't been seen in the US in 50 years, such as header tanks and injector tees. Make sure you get the whole package. European stoves are vented rather than pressurized, so you should also expect to play stump the plumber.

The EPA doesn't require certification of boilers, indoor or out, so there's no problem there. You won't have a UL sticker however, which might matter to your insurance agent. It shouldn't matter to the building inspector because vented stoves don't need UL approval. Best to check with him anyway.