LT90's are fairly small in the owb market. There max output is 90k btu
we should also know that max btu ratings are something we dont need to concern ourselves with to much.
you can heat huge well insulated homes on 50k btu an hour, even in the coldest climates. But the question is how many btu's can my stove produce over a 8, 10, 12, 14 hour period. Then you'll start getting into the real numbers.
for example a boiler may be able to produce a max btu rating of 200k, but over 8 hours maybe only 80k, over 10 hours, only 60k, over 12 hours, maybe only 40k btu an hour.
with that being said, grossly over sizing a stove isnt good, properly sizing is more important, id rather have a customer have to tend the stove 3 times rather than 2 per day on a couple of the coldest days of the year vs over sizing to much and having creosote issues all the time, and a host of other problems due to the stove idling all the time