Today, both solar collectors and solar cells are installed on the roof and all the windows in the house have been replaced.

SVT Nyheter Västmanland has met Mats Lindfors before, and in the five years that have passed since then, he has become even more drastic and, among other things, demolished all the facade bricks to make the insulation 3.5 times as thick.

- The latest inspection showed that the house is now in energy class A and is also better than 80 percent of all houses in that class, he says.

How much did it all cost?

- I have a hard time answering that, but for example the solar cells cost SEK 300,000, of which I received SEK 100,000 in grants.

Then the windows cost SEK 100,000 to buy, and I installed them myself.

As for the facade, I was able to sell the mexi brick and thereby pay for the first two layers of insulation.

Why are you doing this?

- In the beginning it was to lower the bills, but over time the climate benefit has become increasingly important and I really hope that more people get involved.

In the clip above, Mats shows around what he has done indoors and up on the roof.

List: How to make the house frugal - the energy hunter's best tip

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Mats Lindfors has managed to make his house energy efficient right into the A class.

In the clip, you get his three best tips on what you can do.

Photo: Robert Gustavsson/SVT