[elric]

You're wrong on both counts.

Windows don't make for very good ventilation. They are prone to letting in either too much or too little air, which means you're either wasting a lot of heat, or are not getting enough fresh air. Mechanical ventilation with energy recovery is far superior. Windows, of course, are great for letting in natural light and for creating a sense of spaciousness etc.

Heat pumps don't always need big fans, only air source heat pumps do, and even those can be made to be pretty quiet. Not much louder than a gas furnace.

They definitely can warm an entire house (in fact, they do so on a regular basis in many houses in many parts of the world), even in the coldest of climates. Heating a Passivhaus requires only a tiny unit (except for hot water, but let's ignore that for a minute).

[mdp2021]

> Windows don't make for very good ventilation

The point was not with ventilation quality, but with the feasibility and compromises of alternatives. (The strict point was with defining "mandating good ventilation".) Mechanical ventilation with energy recovery may be far superior, but if that means constant noise it will be an issue - to some, a radical issue.

> They definitely can warm an entire house

And I have stated that they can be perfectly inadequate and ineffective (explicitly: which is not contradicted by your statement). Evidently, it will depend on implementation, and again on the expected effect (where temperature is only a partial factor).

Speaking of implementation, I have been in hotels where the heating pumps were unbearable in that they made the room tremble and clearly vibrate.

So, when one speaks of mandating technologies, there are critical implementational issues to be remembered, and the "embrace" drive is to be immediately criticized (just applying one's usual duly Reflection). It is relevant that I have seen in the past legislation mandating some technologies only halfway trough (e.g. mandating valves without mandating pressure control systems), creating immense damages on large territories.

Edit: also:

> Heat pumps don't always need big fans ... Not much louder than a gas furnace

You have not stated they are perfectly silent, 0db - in fact, you seem to suggest the opposite. As said, some do not tolerate background noise.

I do not see where you read anything wrong.

[empiricus]

"Mechanical ventilation with energy recovery may be far superior, but if that means constant noise it will be an issue - to some, a radical issue." I've installed this in my house, it is virtually silent. This is for ~200m3 of clean air/hour. If I turn it on higher you can hear it a little.

[mdp2021]

> virtually silent

Decibels?

I have seen air purifiers publicized as exemplary silent, and people unable to bear the noise of the minimum fan speed.

There may also be a matter of the exact sound - maybe some are less disturbed by (say) a hum instead of a hiss; it probably has to be tried.

[rsynnott]

While I don't have mechanical heat recovery ventilation, I've been in lots of apartments and houses that do (it's virtually mandatory for new builds here). You won't know it's there unless you're in the room that the device lives in, and even then it's not loud.