3 ms·
> And lastly ventilation is probably of of the most tricky, it's very easy to create an energy efficient sealed box, but how do you create a healthy environment
by throw0101a 5y ago
> And lastly ventilation is probably of of the most tricky, it's very easy to create an energy efficient sealed box, but how do you create a healthy environment
ASHRAE 62.1 and 62.2, "Ventilation for Acceptable Indoor Air Quality":
* https://www.ashrae.org/technical-resources/bookstore/standards-62-1-62-2 https://www.ashrae.org/technical-resources/bookstore/standar...
> The answer is normally a complex HVAC system but that then uses power and requires maintenance.
> older buildings are drafty but it comes with health benefits and keeps the building dry by allowing moisture to escape.
Drafty buildings are bad. The air comes in through random cracks and crevices, which may have mold and which also allow bugs and rodents to enter. The rodents may leave droppings, which the flowing draft may then pick up particles from. There are no health benefits to that.
> The answer is normally a complex HVAC system but that then uses power and requires maintenance.
The drafty house you laud above will also use power: in the winter air that was heated will leak out, and the cold air that comes in will have to be brought up to temperature; in the summer the cooled air will escape and the hot (and perhaps humid) air will then need to dealt with to make the building comfortable. And that doesn't include dealing things in the air like dust and pollen (plus the above mentioned critters).
Or you can install some ducting to remove stale air from the house (esp. bathrooms and kitchens), and introduce fresh air (esp. to bedrooms) that is first filtered (MERV 13+) and then tempered via an ERV/HRV core so there's a minimum of re-conditioning needed. The main source of maintenance is the changing of the filter(s). And running an ERV/HRV will use less energy (W or BTU) than re-conditioning the leaky air.
This is a solved problem: build tight, ventilate right.
After air tightness throw on some insulation (while reducing thermal bridging) and you can have a house that uses minimal energy in dealing with environmentals. You just have to make the effort up-front when designing it (or when doing a renovation/retrofit).
- docflabby 5y agoI don't disagree the problem is solved - I the problem in the UK is humidity is quite high most of the time and most houses don't have HVAC and there seems to be a complete lack of knowledge around ventilation - very little thought goes into it for domestic properties, so you send up with these sealed up houses under the guise of "energy efficiency" which makes people ill though mold growth due to lack of air flow. It's probably also contributed to the spread of covid 19.
- throw0101a 5y ago> I the problem in the UK is humidity is quite high most of the time and most houses don't have HVAC and there seems to be a complete lack of knowledge around ventilation Mandating (whole house) dehumidifiers in building codes may help with that if air tightness is also mandated.
- blacksmith_tb 5y agoI live in a Passive House[1] in the equally-humid Pacifc NW, without any kind of dehumidifier. I do have a Heat Recovery Ventilator (HRV) running 24/7, which pulls in fresh air from outside and exhausts indoor air, running them through a heat exchange as they pass each other to save some of the energy that went into the air while it was inside. As a plus it also runs the air through a MERV 13 air filter, which gets rid of pollen and some PM2.5 pollution. 1: https://en.wikipedia.org/wiki/Passive_house https://en.wikipedia.org/wiki/Passive_house
- throw0101a 5y agoOn the effectiveness of various MERVs on various PM sizes: * https://www.greenbuildingadvisor.com/article/understanding-filter-ratings-merv-fpr-and-mpr https://www.greenbuildingadvisor.com/article/understanding-f... * http://dx.doi.org/10.3390/ijerph120708448 http://dx.doi.org/10.3390/ijerph120708448 * https://www.researchgate.net/figure/Mean-PM-25-removal-efficiency-for-HVAC-filters-listed-by-MERV-classification_fig1_280321614 https://www.researchgate.net/figure/Mean-PM-25-removal-effic... Just make sure your system can handle whatever MERV you go with (higher = more back pressure that needs to be designed for).
- blacksmith_tb 5y agoYes, I would go higher than MERV13 if I could, my HRV is a Zehnder, which doesn't support better filters without some modifications.
- throw0101a 5y agoAh yes, it seems that the built-in stuff has restrictions, but there are external boxes that can be added: * https://www.zehnderamerica.com/our_products/comfowell-silencer-and-casings/ https://www.zehnderamerica.com/our_products/comfowell-silenc... Which allow MERV 16 and even carbon filters: * https://www.zehnderamerica.com/product-category/comfowell/ https://www.zehnderamerica.com/product-category/comfowell/ * https://www.youtube.com/watch?v=OrG7oG8Tvp8&t=14m35s https://www.youtube.com/watch?v=OrG7oG8Tvp8&t=14m35s