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If you have central heat you can sometimes configure the thermostat to run the blower separately from the heating element. This creates a nice positive pressure
by jschwartzi 6y ago
If you have central heat you can sometimes configure the thermostat to run the blower separately from the heating element. This creates a nice positive pressure environment. If you have a MERV 10 or better filter installed on the furnace then it's actually pulling in filtered air, as any high enough MERV filter will filter PM2.5 with a decent efficiency. I think they start filtering PM2.5 at about MERV 10, and by MERV 13 they're filtering 90% or more of PM2.5.
- BoiledCabbage 6y agoMERV Table with filtration amounts - https://www.lakeair.com/merv-rating-explanation/ https://www.lakeair.com/merv-rating-explanation/ I'm guessing the table lists filtration for a single pass through the filter. But through constant circulation a greater reduction in air particulate can be achieved. Anyone know this for certain?
- mehrzad 6y agoI would like to know this as well but the way the products are advertised, it would seem that this isn't a single pass-through measurement (see The Wirecutter)
- meristem 6y agoAlso something to consider: electrostatic in-line filtering, which generally combines electrostatic cells plus 2 levels of filters
- ComputerGuru 6y agoWhere is the positive pressure element coming from? Most residential HVAC systems are closed and do not have an intake (note: not commercial, which are typically in the USA required to include an air exchanger or other fresh air ventilation component). Your typical 1980s construction home likely does not have mechanical ventilation, the only inlet would be for fresh air to facilitate the combustion in the furnace (alongside an exhaust for carbon dioxide and carbon monoxide).
- axaxs 6y agoAFAIK, most new construction houses for the past decade or so have some amount of air intake, because houses are built too 'tight' now, but this might be somewhat location dependent.