The basic problem is: a residence containing two humans, various cats and Vats of Fermenting Liquids. And an environment that needs to be 1) Dry enough for comfort, 2) Moist enough for comfort, 3) maintain a defined temperature profile. ‘Comfort’ being the desirable range of temperature and humidity for the precise organism using that space, according to the weather of the day. Which changes with the seasons.

Basic fact: humans breathe out 1-2.5 KILOS of carbon dioxide and 1+ kg of water vapour every day. More if you exercise. And require a steady supply of oxygen and removal of waste gases or horrible things happen. This outgassing includes carbon dioxide, water vapour, cat farts, bacon cooking smells and the aforementioned Vats. I don’t have data on cats or Vats - but I suspect you do and can make decisions accordingly.

I am reminded of a ghastly experience I had back when I worked in insurance and the company hired a hall so that the execs could address everybody all at once about planned changes. It was a beautiful hall, very well built with no leaks. Only they forgot to turn on the aircon in the hall for the event. They realised their mistake when most of the audience (about 2000 people) slowly keeled over and slumped to the floor from lack of oxygen and excessive carbon dioxide. I was one of the audience and was lucky enough to be right at the back and an early beneficiary of the bloke who sprinted to the doors and propped them open so we could all breathe again. Some of the people in the front row had to be hospitalised for observation afterwards. So gas exchange matters.

Also, still air is a WONDERFUL insulator. Nearly every possible kind of insulation does just one thing - it slows down and immobilises air to form a barrier again moving air. Usually by trapping it in a structure of some kind, which is terrible for air exchange. Foam, wool, wood shavings, fabric offcuts, there’s a ton of options at various price points. However, still air does very little to help dispose of waste/unwanted gases. And water vapour. Even double glazing is trapped air between two sheets (or more) of glass. And you can have the best double glazing in the world and it won’t work if the window rattles in the frame cos there’s a gap that lets untreated air in/out. The other kind on insulation is reflective - bounces heat/cold back out from a space technology film of some kind. This too does not permit air exchange because it has to be sealed and continuous to work properly.

Water vapour and ventilation. This is a biggie. And it’s where really serious insulation of any kind meets the real world and fails. Because excessive water vapour/condensation is where mould comes into the picture, and mould inside the house is usually a very bad idea for human/cat health. And the air trapping kind of insulation (any sort) is a prime breeding ground for mould if it gets wet. The reflective kind of insulation also is a mould breeder if warm moist air hits it and you get condensation forming. Most commercial insulation types have some sort of moisture barrier, or you can use building foil which will help a great deal cos it’s reflective too.

House construction is a weird (conceptually) mixture of keeping things out (rain, mozzies, burglars) and keeping things in (cats, loud music, thermal comfort). And sometimes you have to make a choice between two mutually exclusive ends that are both desirable and necessary and you can’t have both at the same time.

So I would would give serious thought to zoning the kind of insulation you require.

Identify the areas that need to be warm and dry, those that can be cooler but must still be dry, and those where water vapour is going to be a daily necessity to be dealt with (bathrooms). And deal accordingly. Sealing off various areas for special treatment seems to me to be a good idea - the Vats may need their own little greenhouse structure for effective temperature and humidity control. Well fitted doors are pretty effective at sealing off portions of a structure. Particularly if you put those fringe thingies around any gaps between the door and the frame. I looooove the ducted heating in my bathroom - whoever put that there was a genius! If the weather is cold enough to need the heating, then condensation just doesn’t happen once the heating is on. And if the weather is warmer, the condensation still doesn’t happen cos I open the window to let the water vapour out.

Also, aircon can deal with a lot of issues but isn’t a total fix - it’s expensive to run year round unless you have solar panels and a battery. But it does do well at air exchange if it’s vented outside and pulls in fresh air/oxygen.

So, in conclusion, standard insulation is a good thing but you need to pay attention to gaps. Aircon is a must if you are going to seal up rooms to prevent moving air coming in from outside. Consider zoning which bits of the house needs what.

That’s more than enough I reckon. You know your own situation best and you’re not afraid of looking at whatever options are available.