Efficiency is one of those often confused elements in brewing. Higher is good, right? Common brewing software has a couple of them, and I think it honestly confuses the issue a bit.

This calculator is really just to help you understand the brewing terminology a bit. Brewbat recipes use only the mash efficiency, and ignore brewhouse efficiency figures completely.

Please read the definitions on the page, this should help you to understand a bit about what they are.

In my opinion, you don’t need to worry about brewhouse efficiency an awful lot during brewday or after even. Brewhouse efficiency is mash efficiency less vessel loss. You can influence mash efficiency somewhat, but not really vessel loss. The hidden spaces in your mash tun, kettle and boiler, as well as loss from evaporation, absorption - are variables that you have little opportunity to change. You could squeeze the wort out of the hops and the grains if you want, but the effect will be minimal.

Instead, Brewbat focuses more on mash efficiency, which I believe you have more influence on. You can stir grains, increase sparge volume, circulate the wort around the grains, use hulls to help circulation. There’s many chances to increase your efficiency during brewday - or just be aware of what your kit efficiency is, in order to predict efficiency in the future.