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Question: My fireplace just meets the width dimension for the DF12310 in the front, but it tapers slightly as it goes back.    It appears that this unit is not completely square but tapers too.  Can anyone tell me what the width measurement at the BACK of the unit is?Thanks.
Document: Awesome fireplace insert! I bought this for an existing fireplace that was non-operational due to cracks in the flue.I was a little skeptical about how realistic this would look, but ordered because of the great reviews. I'm so glad I did! Another concern was that my fireplace just met the minimum front opening requirements and tapers slightly to the rear. For those of youwith a similar fireplace configuration, this insert tapers as well.
I have a small fireplace in my 30 year old townhouse and have been using 3 hr logs for years going through a case a week this last winter. At $25 a week, most of the heat goes up the chimney plus there's a lot of cleanup. I love this insert. It looks great and can actually feel the heat being blown out the front. Plus, no cleanup and instant on with the remote. How great is that.
Here comes the hard part!" But it turned out to be so easy to replace them - just remove the front cover (below the logs) and reach in (carefully - someone with small hands!) and replace the bulbs! Easy peasy! They take normal candlebra type bulbs. If you're thinking of getting one of these I can honestly tell you they are as close to the appearance of a real fire as you can get!
We have had a ventless fireplace with a gas hook up for the last seven years. I never wanted to spend the money on having gas logs installed because of the cost. This product was exactly what I was looking for. It comes in a box all ready assembled. I did have to unscrew the bottom four levelers and take them completely off. It fit in my fireplace opening better and I could push it back further.I just use it for the ambience with the Christmas stockings hanging.
We bought this unit to replace an older one # DF12309. We are completely satisfied with the LED modifications that Dimplex made to the ambience. Our fireplace was useless because we no longer burn wood. It is again is a pleasant viewing experience. The flames and the pulsating embers and logs are extremely realistic.
I am writing this review to tell you that this little unit is most enjoyable. It gives the room a little ambiance. We have a medium sized room which the fireplace is in. We can no longer burn a wood fire due to pollution and the chimney not working properly. With this being said, the unit gives off a small amount of heat for the size of the room. If it were in a smaller room, I am sure  that the heater would be more efficient.
The LED lighting in the logs glow, dimming and brightening, just like burning logs at the embers stage of a fire. I have a 70&#34; flat screen mounted above the fireplace mantel and was concerned about heat and soot over time causing it damage. (TV over the fireplace is a building trend in this area) This fireplace insert is a great solution. I would recommend this unit to anyone having a TV over the fireplace or someone that is simply not interested in maintaining a fireplace and chimney.
I enjoy this fireplace insert. During the evening hours, with the lights low, this unit looks like a real fire is going in my fireplace. I even placed a fireplace screen in front of it to add a more overall realistic appearance. Because of the recent cold weather I've been using the heat function for a little extra warmth in the living room. (not a great amount but noticeable)  I have to admit that in a well lit room the unit is detectable as an imitation flame and insert.
This unit looks good,very convenient to use, two heater settings, easy on and off, fits easily into an existing fireplace at least 28" wide, even with tapered back. You should shut off the flue to minimize heat loss! Excellent value!
We turned the unit on at high heat, found the fire look to be just fine and the temperature in the room was 70 degrees by the end of our movie viewing. We are very pleased with the product and would recommend it to anyone who has to think about budget. There are units out there for $500 and up to $1000 but I can't imagine that they would heat my room any better.12/2011 We've had the unit for a year now and it continues to work beautifully.
Answer: It is about 8 inches less than the front.