Agreed with everything said here. Both stoves are beautiful, both cats, I'm partial to the BK (otherwise I'd own two Hearthstones), but I can see the appeal in both. I can't speak good or bad about the Hearthstone, so I'll just give you the reasons I bought the Ashford 30's, and tell you how I run them:
1. I wanted a cat stove for the ability to turn down further and get more even heat. The non-cats follow more of a "pump and glide" heating profile, more BTU's in the first 2 hours, and then tapering off. This can work fine when you're not sitting directly next to it, as the mass of your house and every object in it acts as a big capacitor, to level off the effect. But one of my stoves is located a mere 10 feet from my desk chair, where I sit and work all day and night, and I was looking for tech that would give the most even possible heat.
2. I wanted a stove that had the widest possible range of outputs and burn times, so it would suit my schedule as best as possible, over the widest range of months. When I bought these stoves (pre-COVID), my wife and I were both gone from the house for most of 12 hours per day. I wanted a stove I could load at 6am, and arrive home to a warm house at 6pm. In the dead of winter, this is possible with either a cat or a non-cat, just load the firebox full and set for a 12 hour cycle. But as most describe managing their non-cats on lower heat load days by just having shorter fires with fewer splits of wood, I knew that would not work for my scenario of needing heat 12 hours later, not just for a few hours in the morning when I wasn't home.
3. One of my stoves is installed in a small 200 sq.ft. room, the 1770's kitchen of this house, now used as my home office. Knowing I'd need a LARGE non-cat to make my target 12-hour burns, I feared it would roast us out of this tiny room when we were home.
4. Because my stoves are jammed back into old cooking fireplaces (one shown in my avatar), any heat radiated off sides/back/top is simply soaked up by the stone, and much of it radiated outside. So, I was looking for a stove that had a full double-wall convective jacket on ALL sides. This is why I had asked about your house construction, as it looked to me like the Manchester has a convection deck on top, but the sides are radiant. The Ashford 30 (all of the BK 20's and 30's) are a welded steel box lined with firebrick, with cast panels (or sheetmetal for Chinook?) hung on the outside, forming an air gap between the firebox and the outside of the stove, thru which air is moved by either natural convections or your fan kit. When running the fans, the outer plates stay so cool you can touch them without serious concern for burns (nice feature, if you have little'uns), and very little heat is radiated from them into my exterior stonework.
So, that was my thinking going in. Now that I've put 60-70 cords thru them, I can tell you a little about how I operate them.
1. I run the stove in the older part of the house (aforementioned 1770's kitchen, which is actually the 1734 bedroom
) on mostly 12 - 16 hour cycles. In other words, I start and end each heating season loading this thing around dusk, and setting the dial to the marked spot where I get about 16 hours active cat. This is the mode for all of October, much of November, end of March, all of April, an often into May. When it gets colder, namely late November thru mid-March, I shift to 12 hour burns and loading twice per day. I don't worry about truly generating enough heat to keep the entire house warm (I'd need 20+ cords per year for that), I just keep that stove going, and let the oil-fired boiler top things off to our desired temperature.
2. I run the second stove in one of the newer additions on 24-hour cycles thru the coldest months, loading it every day around dinner time. In warmer months, like right now, I'll just put half loads into it at dinner time, and let it go out mid-morning, since that part of the house has too much solar gain to keep a stove going on a sunny day above 35F.
3. Occasionally, I'll fill the stove in the newer addition full, and then realize the next day is going to be warmer than I had assumed. That's when I turn the thing way down, and get the 30 - 36 hour burn times (measured as active cat time) that several of us have reported for the BK 30's. Yes, they can do it.
And I'd be remiss if I didn't mention the bad, with the good:
1. BK shipped me two "transitional" stoves, right between the original "30" design, and the "30.1". My stoves have a mix of features from each, I even got one "swoosh" dial and one "numbers" dial. All good, it's more conversational curio than anything else, with one exception: the stoves had the new ash-dump hole location over the old ash pan. Total screw up, as the ash would dump over the rear of the pan, and a large portion of hot coals and ash would land on my floor. However, BK did the right thing here, and made a special retrofit series of ash pans for me (and likely one or two other customers in the same boat), so that we could swap our pan assemblies to one centered under the new ash hole. I'm sure this ruined their profit on these few stoves, but they always seem to do the right thing, by their customers. The fix works perfectly.
2. Some have reported smoke smell issues with their Ashford 30's, in past years. I believe BK resolved each of these cases, with the exception of two customers who just wanted to trade in. In fact, I had heard thru this forum that one of the "trade-in" stoves is now in another member's house, and working fine with no smell, but that's beside the point. The "bad" is that they had this problem, and I believe there have even been one or two more in recent years, but the "good" is that BK has worked with the customer to either resolve the issue or work out a trade in every case. Personally, I never have any smell from either of mine when burning "normally", but I have caught a whiff of something acrid on a few occasions, only when I'm cranked
way down for a 30+ hour burn in warm weather on the stove in the newer wing. In my case, I think it's due to some combination of a very short pipe (something like 13 - 15 feet), warm outside weather, and the very low burn rate, as it has NEVER happened on the stove with the taller pipe, and it never happens under normal weather or burning conditions. The two or three times it has happened in 7 years, it went away as soon as I turned up the dial to increase burn rate a little.
3. A few of us with very tall (eg. 30 feet) chimneys will have some issues with fly ash clogging the combustor, when the stove is run on maximum setting. It appears BK was trying to improve on their "dirty glass" image, earned on the King and Princess, and designed a more aggressive air wash system on the newer 30's and 20's. In most cases, reports here would indicate this works as it should, keeping the glass cleaner with no ill-effects. But with a too-tall pipe (mine generated 3.5x the maximum allowable draft spec), and when running extended periods on high (as I'll sometimes do on weekends), it can stir up enough fly ash that it begins to coat the combustor over time. This was not a huge deal, the dust can be vacuumed out with very little effort, but it did mean letting the stove go cool to do it, and preferably removing the combustor to do a good job of it. I resolved the issue by installing a key damper on the pipe above the stove, to dial my draft down from 0.21" WC to the recommended optimum 0.05" WC, and have had no ash clogging issues since then.
When I read your comment about letting your furnace still carry part of the load, my assumption was you were thinking like me, that you'll just keep a stove going to carry the majority base load, and let the furnace modulate final temperature atop that.
