Give him one safe room and keep it that way
During a long power cut, a Domestic Shorthair does best confined to a single interior room rather than roaming a dark, cooling house. Interior rooms hold heat longest and keep him away from the hazards outages create: open doors during torch-lit trips outside, dangling cords from temporary equipment, and rooms being aired. Set up his litter tray, water, food, and a carrier or box lined with blankets in that room and shut the door. A cat who can survey one predictable space settles; a cat patrolling a whole silent house startles at every sound the building makes as it cools.
Warmth without dangerous improvisation
Keeping a Domestic Shorthair comfortable when the heating stops is mostly about insulation, not improvised heat. Pile blankets into a nest inside his carrier or a cardboard box with the opening turned toward a wall, and let him choose it; cats are expert at finding the warmest fold. Close curtains and hang a blanket over a draughty window in his room. Never bring a fuel-burning heater, barbecue, or generator indoors or near his space, because the exhaust that endangers people endangers a smaller animal faster. Candles are a fire risk around a curious cat in the dark; use torches and battery lanterns placed out of paw reach instead, and keep portable heater cords taped down or out of the room entirely.
Water, food, and the litter tray in the dark
Power cuts disrupt the routines a Domestic Shorthair organises his day around. Keep fresh water in a heavy, spill-resistant bowl in its usual relative position, and check it whenever you pass, because a stressed cat may drink less and dehydration creeps up quietly in a cold house. Feed at his normal times, by torchlight if needed; the schedule itself is comfort. If he eats from an automatic feeder or drinks from a powered fountain, switch to manual portions and a plain bowl for the duration rather than leaving him dependent on dead equipment. Scoop the litter tray more often than usual, since a cat confined to one room will refuse a tray he considers spoiled, and refusal leads to accidents and more stress.
Reading his stress and knowing the exceptions
A Domestic Shorthair in a power cut will probably hide, sleep more, and eat cautiously, and that is normal coping rather than illness. Leave hiding places alone; dragging him out for reassurance serves the humans, not the cat. What does need attention is a cat who has not eaten for a full day, has not used the tray, is panting or drooling, or feels noticeably cold with ears and paws chilly and movement sluggish. Very young kittens, elderly cats, and any cat with a condition your vet manages should be moved to a powered home or a vet clinic sooner rather than ridden out. If the house becomes genuinely cold, relocating the cat beats layering more blankets.
Household coordination while the lights are out
Outages scramble households: one person thinks another fed the cat, a door to his room gets left open during a torch run, and nobody is sure when the tray was last scooped. Agree one spokesperson per task and say completions out loud, then write them on a note stuck to his door for the next person. Keep his carrier, a torch, and his food together at that door so a sudden decision to relocate him is quick. Pulling those updates into KinsLe Messenger gives the whole household one per-pet thread for your Domestic Shorthair's outage care, so feedings and warmth checks are confirmed rather than assumed.