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Comment by stormdennis | Hacker News Reader

The focus today is also on insulation ie preventing heat loss. That means making houses less draughty. But draughty houses are also healthy houses. More fresh air and less mould. I think it would be better if people accepted that in Winter it's going to be colder indoors so wear thermal underwear etc.

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Its called heat recovery ventillation, its the cheapest and most cost efficient improvement you can make to your life, house and energy bill.

You will have fresh air, control humidity and use 95% of the heat in your house air to heat incoming air from outside. It solves problems with mould and humidty. You can seal your house from the elments

A 'box' that does everything costs just 1 grand, just install ducting and you are done.

Do you know: is this tech useful for hot water radiator/boiler systems or is it just for air?

In Europe where most homes only have radiant heating/cooling, new homes have a separate fresh air system, which would include an ERV.

Making houses less draughty is just one point (convective heat transfer) another point is making walls conduct heat less to reduce conductive heat transfer.

Uninsulated houses often has higher risk to mold because of cold walls. Warmer air has a higher capacity to carry water as humidity. When it hits cold walls the air cools down and the water condensates leading to mold.

Drafty houses are not healthy houses: timber needs to be able to dry out to stay rot-and mold-free, but draftiness is associated with weakened immune systems and therefore poorer health. The draftiness rule only holds for older houses constructed before insulation, where the draftiness is needed to counteract the cool, stone/brick basement collecting moisture. A modern house design for insulation should be tight and mechanically ventilated, both for the maintenance of the structure and for human health.

It is possible to considerably improve the heat insulation of a building while still allowing turnover of fresh air. We don't specifically want to throw away the heat, we just want to change the air, and you can arrange to do that. The laws of thermodynamics forbid us from arranging to keep all the hotter molecules and lose the cool ones, but they allow us to insist on a roughly fair swap, hot air going out gets cooler, cold air coming in gets warmer.

This will be more expensive than just sealing everything up and hoping, but that's the sort of reason why you want somebody figuring out how to do it properly and only subsidising work that we know insulates homes without destroying ventilation so that they're horrible to live in. Modern homes here have much better heat insulation than when I was a kid, yet there isn't the damp problem I saw in cheaply retro-fitted rental places where I lived.

Ya lost me half way, but sounds like you’re describing HRV

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