As your fridge gets older, the door seal can become less effective. The hip bump or door slam that used to close it firmly may no longer do the job. If you've walked into the kitchen recently to find the door ajar, your food warming and your electricity bill climbing, here's what to do.

First off, an obvious point: make sure that there are no food items too near the front of the shelves. Even if everything seems to fit in, there may be a bottle or a carton in the door that’s hitting something inside and stopping the fridge door from closing properly.

Once you’ve rearranged things (just to be sure), the next thing to do is check the door seal. That’s probably where the issue is.

To see if the rubber door seal – also known as the gasket – is at fault, try the paper test.

Place a piece of paper in the seal and close the door firmly. If you can pull the paper out without the door seal tugging it at, that’s a sign that the seal is compromised.

If that's the problem, there are some easy tricks you can try to fix it.

First off, get a sponge or cloth and a bowl of hot water. You can add a drop or two of washing-up liquid to the water but don’t add loads and let it foam up too much as it can dry out the seal. Don’t use any other cleaners on the gasket – especially not vinegar – as they can damage the rubber and make the problem worse.

Gently clean all over the door seal, wiping away any stain or crumbs.

When it’s perfectly clean, move on to the next step.

You’ll notice that the door seal has folds, like a concertina. Over time, they can become compressed, which will make the seal less efficient. Carefully run a finger along the length of each fold and open it up. If there are warped areas, you may be able to press them back into place.

Last step! If you notice that the rubber has dried up and become brittle, there’s something else you can try.

If you have some Vaseline, you can take a cloth, scoop up some Vaseline and rub it into the gasket. This will soften it and help it to form an effective seal again.

If the gasket is too warped to push back into place, or it has large cracks, you’ll need to replace it. In most cases, you'll be able to buy a replacement seal for your door and fit it yourself. Find your fridge make and model and look for a replacement gasket online.

Finally, if you think your fridge is on its last legs and you need to replace it, check out our round-up of the best fridges we've tested.