*EDIT*
Okay, saw from your other post you live in Northern NY. It will probably by perfectly sized. I did a lot of research online before purchasing my insert and the PE Summit is probably the best out there. The Summit has a lot of features and design tricks that, unless you used or saw another type you wouldn't appreciate. So, I told my wife the Summit is what we need, want to come with me to the store? She does and checks it out, she looks at the window and that was the end of that. We weren't getting it, window too small. We ended up leaving with the Hearthstone Clydesdale which has a huge view, huge. I think you'll be happy with whatever you get, but the PE Summit has many features I wished mine did.
It has a newer secondary burn that's covered in a sheet of stainless. What good is that, well the older design like mine, are often tubes with holes in them and above that is a 1/2" or so piece of insulation. It's possible for me to put a piece of wood in there with a stick sticking up and break the piece of insulation but that's rare. I don't know anyone that's done it or needed that piece of insulation replaced from doing that but, possible. The insulation is about 3" above the bottoms of my secondary air tubes so it's a decent distance from the wood. The PE Summit you're free to jam as much wood in there as possible, its baffle is protected by a sheet of stainless, no chance to wreck it.
Next, during a chimney cleaning the task I have to remove 6 bolts, remove I think it's 8 pieces of soapstone, loosen 2 more bolts, slide the baffle out, protect that piece of insulation so it doesn't break during the cleaning, and then clean the chimney. Afterward, do the reverse. The Summit, if I recall it's 2 pins and out it comes. Some older inserts, not only do you need to remove al the firebrick on the sides you also have to remove each individual air tube. Yikes! This isn't a big issue, it only applies once a year because that's how often I clean my chimney and probably adds 20 minutes but one of those things that shows PE's good design.
Mine has channels that run around the bottom, loop up the sides, over the top, and out the front. The Summit Insert has a full, floating firebox. That's superior because it's more surface area.
The Summit has EBT. I really don't understand why but, although they advertise it extends burn times I can't see how when it opens additional air. My theory behind it's true purpose (and maybe I'll be killed), it keeps the window clean because when it does kick in, it's usually about the phase of the fire that helps clean the glass giving it extra cleaning ability. Which brings me to the next point.
Loading units front/back is problematic for dirty glass. Mine, loading front/back covers my glass in no time, besides it's obvious my unit is designed for side/side loading anyhow. The PE Summit can load front/back and is probably one of the cleanest glass units out there. That's amazing to garnish that title for a front/back loading unit (it can also be loaded side/side). Also, means less work on your part cleaning the glass and, if you haven't cleaned the glass of any stove/insert it does not want to come off and a lot of work.
The Summit I think is the only insert that can use outside combustion air without any modifications to your house using the clean-out of your fireplace or it can use internal air. That's pretty clever and the only one I know of that can do it.
The one thing it falls short is the size of the viewing window which, isn't small it's tiny. That was enough for my wife to say nope. I wouldn't think twice if your goal is strictly heating your house. The PE Summit is probably head of its class. If you're giving thought to the Hearthstone Clydesdale let me know and I'll tell you about it but, it's a different experience because it's soapstone. Soapstone units are slow to heat/cool so very different experience which can be a good/bad thing depending on what your expectations.