The thread title says it all! My bottom line is I’ll shell out extra $$ for a BK if I can be confident I’ll see a 15% reduction in the electricity/wood I use, I’m looking for advice on whether that’s realistic. I'm a newbie to this forum, also a newbie to BK's, but I’m not a newbie to fires in general. I'm not trying to get help on whether BK's are good fires, some dozen hours of reading (including 25 pages of pure gold here on Hearth.com discussing Trev's King last year!) convince me they're great fires, and for many people they're probably the best fire. But I'm a unique snowflake like everyone else I'll try and convert NZ speak/metrics to America talk. Please bear with me if I get any conversions wrong! My house; It’s a wooden 20's Villa, approx. 1300 down, 700 up (converting from my m2 to your ft2). When the new fire goes in I'll have full mid spec underfloor insulation with a windwash barrier I have full mid-high spec ceiling insulation I have partial, low spec wall insulation The house is largely single glazed, it’s as drafty as you expect a house of its age to be. I have additional heating capable of putting out up to 40,000 BTU's/hour (again converting from our KwH to your BTU's). It can operate on low quite efficiently. I want to burn approx. 7 months of the year, minimum temp we get down to is about 20F (-5C) and that's rare. Ideally I want a fire I can bank for 10+ hours overnight and during the work day Weird New Zealand factors; We have strict emissions and efficiency criteria but our government doesn't trust the EPA so a company here in NZ has to pay a boatload of money to get a fire tested here in NZ before it can be sold and installed. Companies will only pay the money to get it done if they think there’s enough of a market here to warrant the investment. And we're a small market! That means many great fires (including the BK King) can't be used because no company thinks they can sell enough to make it worthwhile getting it certified. We’ve only been able to install the Sirrocco for a few years I only have access to a moderate amount of free wood on my half acre and wood is pricey here. I typically burn 3 cord a year, 1 I cut myself and 2 I buy. Low BTU softwood is ~$220 a cord, high BTU hardwood is $400+ Secondary Burn and Cat models are rare. Less than a dozen fires available here have some form of one or the other. No other reburn/Cat model suits the aesthetic of our lounge so my wife has ruled them out. My criteria; Basically money. I’m willing to pay more for a Cat/reburn but only if I can be reasonably sure that I’ll get the money back. Given my house and alternative heating above, I’ll need to see somewhere around a 15% reduction in the firewood/electricity I use to keep my house at a comfortable 70F (21C) through the 7 months I’ll be burning. Whatever I install will be to code/specs, it will have a straight ~25 ft flu, I will capture heat for the first 3-4ft only. So geek me up!! What additional info do you need? What do people recommend?