I'm considering various options for home improvement and improving the home economy and resource/climate efficiency. One area of focus is the fact that I live in Denmark and it can get quite cold, and so HRV and ERV fans seem like appealing options, especially the single-room ones, as adding an entire ventilation system is expensive.

The point is to ventilate the area while retaining the heat generated from indoor heating in winter, as airing out using the windows (the only other ventilation source) runs the issue of heat loss and inefficient air exhaust if I'm not generating a draft from another room, causing heat loss.

Before that, however, I am a tenant, even if the rules are a bit different where I live from the usual private situation (effectively a form of state-regulated, yet non-government public housing organization called "Almen boligforening").

I'm not very experienced in DIY work, but I'm also not the only one I know nearby capable of contributing to a project like this in terms of carpentry/electric engineering capacity. I would like to ask here first for reference, though.

I am highly uncertain whether or not I would be allowed to make any large-scale home improvements, especially those that can be seen on the outside as a permanent modification to the aesthetic, as the local organization really values the "rustic" aesthetic.

It is also worth noting, as I update this post, to note that this is not the first action I would want to take for home improvement, noting things like weatherization and consumption optimization, but those seem to be a lot easier to have answered through Google than what I'm asking, as anything I ask just comes up with more generic "How to install a HRV fan" videos.

And so, with that as context for an answer, I ask the following:

Is it, from your views, practically feasible/efficient, in terms of cost-savings as a result, among others, of the less-airtight seal of a dismountable wall? for me to make some sort of heavily insulated wall that can be dismounted from a window in a jiffy, with one of the single-room heat/energy-recovery fans in them, plugged to an outlet, easily removable if I receive complaints?

I'm not sure I'd be allowed to glue it on, and so I'm not sure if there's much of an easily-removable adhestive option that would give me a tight seal to maximize efficiency, yet also allowing me to dismount the construct following complaints.

If there's something like this already offered in the market, I'd probably want to know as well. It would likely take DIY work, but would reduce it, and would probably be a more efficient product than what I would expect to make by hand.

Thanks for the answers in advance.

  • Updated to reflect the situation better. It's to retain heat already generated indoors while ventilating. – Corspide Jan 8 '20 at 1:58
  • HRV seems like the right choice (vs. ERV) because they will always do what they are designed to do, as opposed to ERV which perform well in low humidity outdoor environments but are said to be ineffective for conditioning very humid outdoor air. I would question, for a single-room application, whether the energy payoff would be realized after the expense of the unit and the energy to power it.... – Jimmy Fix-it Jan 8 '20 at 3:49
  • Things like weather striping are usually ok for a resident to do. Any work that modifies any portion of the structure or finish, written approval from the owner would be needed prior to the work starting. I don’t know your electrical laws but in the U.S. a resident could not install an HRV because the electrical would require a license (A home owner can do this in most areas but if a rental then a licensed electrician is needed here for most states). If you figure out a way to do it and keep it “temporary” then a cord and plug could be used (possibly) if allowed by your laws. – Ed Beal Jan 9 '20 at 15:49

The question is rather broad as asking mostly "is this feasible", and therefore maybe off topic, but it's an interesting question and here's what comes to mind...

I picture a panel, either hinged to the interior of the wall or to be mounted on shelf brackets or similar and with some sort of clamp to press it against the window casing. This panel would be a sandwich of plywood or other sheathing panel and extruded foam sheet. Your ERV unit would be mounted to it appropriately, and foam tape around the edge would provide an airtight seal.

Now, one has to consider the real-world ecological payoff of such a thing. Every component, down to the screws and adhesives, has an ecological cost associated with its manufacture, shipping, and implementation. Is that really worth doing? What's the payoff time when compared to the pollution and energy savings offered by the ERV? Are there other low-hanging fruits that would make more sense, such as reducing hot water consumption and sealing leaks in the building envelope?

I admit that I'm not the type to have an interest in detailed investigation of that question, but it's worth considering at a high level. Good luck.

  • Thank you for your response. Without doubt, this was not my first consideration for home improvement, and I have many others I would like to consider first, such as the weatherization you mention, likewise, I would want to consider all the parts of building the product, such as minimizing shipping times and buying from more sustainable companies to the extent that I can verify. I will try to update the question to make it a little less broad, and I hope it will help a bit. – Corspide Jan 7 '20 at 21:20
  • You're welcome. Please take the tour so you understand how this site works. – isherwood Jan 7 '20 at 21:54

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