Looking at the single-sided insert. They are all custom made is my understanding.
In Canada, so EPA rating isn't that kind of concern for me. I would assume their application is underway, so it might be fair to say they are not yet EPA approved (as in, keep an eye out for it...)
I am going to order an insert from Don-bar for this spring. Looking at around 3000.00 all in, plus shipping, but I'm going to Quebec city to pick it up with the little lady (I owe her some romantic time, and Quebec City is a wonderful destination. OH, the food... good thing we are both meso-ecto types.)
They are made of steel, so we're talking about a lot of heat from this unit. I have not (yet) spoken with anyone who has a Don-Bar insert. However, my WETT inspector came by yesterday (he installs inserts). He was blown away by the amount of heat that the steel units from Quebec he'd recently seen were producing. He really liked the idea of a steel unit from Quebec for my application.
I deal directly with the folks at Don-Bar, and the insert will be made to fit exactly. I have never imagined such personal service for such a product. Very, very impressed, worth a few bucks more on price. My heating bills (nat. gas) are crazy, so I'll re-coup the cost within 3 years. And... just my opinion, but when I sell the house (if..?) I know this unit will be a fine feature deeply appreciated by buyers. It does not have that... kinda clunky insert look. It looks classy all the way, to me. If the quality of manufacturing is as high as I hear, then the Don-Bar insert seems like a good investment on all fronts.
I am also big on the idea of the Ash-dump blower system, for a few different reasons. But don't get me started on that.
And the Door... the feature that sold me. This unit is a 'traditional' open fireplace one minute, and a high-efficiency heater with a _full_ fire view the next. Romance for the little lady, roasted marshmallows for the kids, and cheap heat for dad without the teeny fire window effect. I love it.
The only mention (with highest praise, and I wrote this reviewer, who confirmed his praise) of them on the internet I can find is here:
http://www.hvac-for-beginners.com/wood-fireplace-insert-ratings.html
My impression of them so far is excellent. Still, I have yet to install the unit (until this spring), so I can only give my very early impression (and that is all good so far.)
With 5 cords of wood just stacked stacked, you can bet I am very eager to write an experienced review about them ASAP!