Tova

One thing worth ruling out first because it costs nothing: check on level ground.

A very slight downhill is enough to make a bike walk forward at a junction, and junctions are frequently cambered or crowned. Several people have chased a clutch for a week and then found the bike sits still on a flat car park.

Not saying that is your answer - the warm-versus-cold difference argues against it, but establish the baseline before spending money.

Worth watching one thing while you wait: whether she is favouring the tail.

Tail injuries in cats can be more serious than they look, and the base of the tail especially: nerves that matter run through there. Signs worth a vet call rather than patience: holding it oddly, not lifting it, flinching when it is touched, or any change to litter tray habits.

From your description she is eating and behaving normally with everyone else, which is reassuring. Saying it only because the behavioural story and a physical one look identical from across the room, and only one of them gets better on its own.

Matt and chalky, and the tins were left by the fence with a supermarket own-brand label. That is reassuring - I had been imagining the worst.

Two litres a day is unremarkable, and the reason it does not feel humid is that humidity is a percentage, not a quantity.

A moderately sized room holds a surprising amount of water in the air, and more keeps arriving: people breathe out roughly a litre a day each, showers and cooking add several, drying laundry indoors adds a couple of litres per load, and in a cold house moisture moves in from unheated rooms and from the fabric of the building itself.

The machine is not emptying a reservoir - it is intercepting a flow. It will keep collecting for as long as moisture keeps arriving, which is forever. That is not a fault and it is not evidence the room was unusually wet.

Also worth knowing: a room at a comfortable 50% relative humidity still has a lot of extractable water in it. "Does not feel damp" and "nothing to collect" are different statements.

For question 3: honestly, no, and the arithmetic is the reassuring part.

An oven lamp is typically 15-25W, and it is only on while the door is open or while you are watching something, which totals a few minutes a day. Call it ten minutes daily at 25W and you are at about 1.5 kWh a year. That is a rounding error next to the oven's own consumption, which is measured in hundreds of watt-hours per use.

The replacement frequency is worth a look, though: an oven bulb dying every year is on the short side. They usually last several. If yours goes annually, the suspects are vibration from the door slamming, or the bulb being a cheap one, or a fitting that is not seating properly.

Buying the right type - usually a 300°C-rated appliance lamp rather than a generic bulb, often fixes the yearly ritual on its own.