For allergy sufferers, open windows bring fresh air but also pollen and dust. A window filter lets you keep the fresh air while blocking the misery-causing pollen.
Tape the template to the return air duct between the filter holder and the furnace. Stay at least 6 in. away from the filter holder. Then drill screw holes in the duct.
Screw the monitor to the duct and install the batteries. Turn off the furnace and press the calibrate button. Then install a new filter, turn on the furnace, raise the thermostat setting and wait until the blower kicks in. Press the calibrate button again. Then install the cover.
The claims made by furnace filter manufacturers are true: A high-efficiency filter can provide some relief from allergies. By trapping smaller airborne particles, these filters make the air in your home cleaner and less irritating to allergy sufferers. But before you install a high-efficiency filter, there are a few things worth knowing:
Many filter manufacturers follow the Minimum Efficiency Reporting Value (MERV) rating system established by the American Society of Heating, Refrigerating and Air-Conditioning Engineers (ASHRAE). The MERV number is an indication of the filter’s effectiveness at trapping particles. A MERV 1 filter traps dust bunnies but allows most dust to pass right through, while a MERV 16 traps bacteria and particles as small as .30 to 1.0 micron and is used mostly in operating rooms. If you don’t have allergies, a MERV 7 furnace filter will work just fine in your home. And if you do have family members with allergies, go up to a filter with a MERV 11 rating.
However, some filter manufacturers and retailers have developed proprietary rating systems like Microparticle Performance Rating (MPR) or Filter Performance Rating (FPR). Before you buy a filter based on an MPR or FPR rating, look for a MERV to FPR/MPR chart online (nordicpure.com/info/what-ismerv is one site) or contact your furnace service company for a filter recommendation based on your particular furnace.
Window screens for double-hung windows that filter out pollen and dust are available from several online suppliers (search for “window air filter screen”).
These filter can keep out almost all dust and ragweed pollen. The drawback is that unlike a conventional insect screen, they won’t let breezes blow through the open window.
To install the screen, just open the window and put it in the opening as shown. You can buy the screens online or at some home centers. The filters are replaceable.
You can leave the screen in year round, but you’ll only need it when pollen is aggravating your allergies. Pollinating grasses, such as orchard and Bermuda, grow in the late spring and early summer. Ragweed, which causes most “hay fever,” is prevalent in the late summer and fall.
If pollen is still a problem, put an air cleaner (also called an air purifier) in your bedroom. The units work by circulating air and filtering out airborne particles such as pollens. Choose a unit that’s made to clean a bedroom of your size or a larger room. Be aware that while some air cleaners have tested well at filtering out pollens, others have not. Research air cleaners in consumer magazines before buying one.
A filter that’s plugged with particles may not look dirty. And the manufacturers’ life-span estimates are nearly worthless. So how can you tell when a filter is dirty enough to stress your heating/cooling system? You can’t unless you install a filter monitor. They’re available in two versions: