Marco, you're very right about climate making a big difference.
So, I made a very long post here giving a half dozen cost-based arguments for HRVs and powered ventilation. They were so good that they are scary. And the costs which people could avoid are so large as to be life altering.
There is much much more to this issue than solder fumes. Do you want to hear them?
HRV makes sense if soldering is your job. For a hobby I'd be surprised if you ever recover the cost from the lowered heating bills compared to just venting period and having a little more incoming cold air.
With all the potential problems caused by things in our indoor air, there is now a growing need for powered ventilation that impacts people in a great many settings. Much newer construction in the US and elsewhere needs powered ventilation. Other problems exist commonly in older homes, also people retrofit and bring a lot of things into their homes that have problems. They are causing hundreds of billions of dollars annually in increased health costs for the world, and those costs are rising rapidly.
Some of the causes are non-obvious. For example, flame retardants used in foams used in furniture and insulation. Plastics used in carpeting and flooring. Binders and plastics used in construction materials and wood substitutes. The ambient dust in many homes is now estrogenic.
Also, there are major problems with mold which can occur due to humidity and once the toxins that cause these problems are generated some of the worst ones persist indefinitely until physically removed.
When these problems occur, sometimes fixing them can entail substantial costs. Costs that can exceed the cost of completely replacing the building. The human costs of these issues can be astronomical.
So HRVs to constantly dilute indoor air with fresh air all the time make a lot of sense for everybody, even people who do no soldering at all, ever.