What you need to do to prepare your home for a blackout:

Seal all possible cracks through which cold wind can enter the apartment with polyurethane foam or construction tape. And update the insulation on modern windows - it becomes dull over time and does its job worse.
Seal the inside of the glass with bubble wrap. Taping up your windows is generally a good precaution and reduces the risk of them being shattered by a nearby explosion. And bubble film is an additional and very effective insulating layer.
Replenish food and water supplies. Not only drinking water, but also technical water, in case of a long-term water supply outage. Minimum 2 liters of one and the same amount of the second per person per day. Enough to last a week. It’s the same with food, only preference should be given to dry rations, canned food and foods that do not require special preparation procedures. Freeze-dried food is especially good in this regard, which can simply be poured with boiling water.
Replenish gas reserves. Most likely, you already have a gas burner or camping stove, so all that remains is to purchase additional fuel for them. And once again repeat the rules for its safe storage.
Refill your first aid kit. Be prepared for the fact that pharmacies may either not be open or that they will not deliver medications on time. So replenish your stock of medications, both general-purpose and those designed specifically for your problems.
Replenish supplies of warm clothes and things. Any solution that helps you stay warm during a blackout is a good one. So buy extra warm blankets and blankets, and update your fall/winter wardrobe. You can even buy a sleeping bag - it will also increase your chances of surviving a long heating outage.
Powerbank

What things are worth buying?
Chances are you already own some of the items on this list, especially if you're into hiking or any other outdoor activity. But not all people will be as prepared for a possible blackout as you are.

Flashlight. To solve everyday problems, a regular headlamp set to minimum power is quite suitable. The main thing for it is the ability to work continuously for more than 4 hours and the presence of a battery that is charged via a standard USB connector. The ability to use replaceable batteries is also useful.
Powerbank. A device that absolutely every person who has a smartphone should have. And if you consider that telecom operators also promised to provide Internet access even during a blackout, the benefits of a power bank become even greater. Which model should I buy?
Gas-burner. It is used for both cooking and heating. True, in the second case it wastes a lot of fuel. There are also more advanced options - integrated cooking systems and travel stoves, but they are more expensive and not so versatile.
Thermos. Preferably together with a thermal container so that you can store both liquid and pre-cooked food. Criteria: at least 4 hours of heat retention, durability, compactness.
Sleeping bag. In general, it is a useful thing in the household, especially if you have to receive unexpected guests. And in case of blackout it will be useful

We continue to believe in the Ukrainian Armed Forces, air defense forces and our power engineers. However, this does not at all prevent us from taking specific actions to prepare for possible emergency situations. Especially in the event of a long shutdown of heating and light in the coming winter. Buy the right equipment and control your supplies - and you will be able to survive this winter without any major losses.