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8

There are many DIY air quality test kits available, that might be the best place to start. This one checks for bacteria on HVAC filters and vents. This one from AirLab actually samples the air to test, though it is a bit pricey. You could also call a professional to come in and test the quality of the air in your home, this can be expensive so I would ...


7

The filter sits between the air return duct and the heat chamber, BEFORE the cool air enters the furnace. The air flow arrow almost certainly will point at the furnace, not away from it. If the filter sat after the furnace, there would be potential hazards associated with it, like possibility of fire (hot air hitting a cardboard frame) and release of nasty ...


6

As Tester101 mentioned (and he really should've made it an answer, because it's at least a partial one), the filter could restrict airflow to the point where your furnace overheats. Hence the 'Limit' error. But wait! Trying a cheaper filter, or running without a filter, isn't a good answer. You'll shortly find that the furnace won't run at all, with or ...


6

The thin fiberglass filters (usually blue in color) are referred to as "rock catchers" by some of my fellow construction friends. They don't do much to catch dust, but they'll stop anything large from damaging the blower. It's entirely possible that it was changed before you moved in and just hasn't had enough time to catch the little dust that it will ...


5

Some programmable thermostats do base their filter reminder on run time. However, the problem is looking at a filter, their change out period is not mentioned in runtime, it just says 'every 6 months' or something like that, so it's a little tricky to convert sometimes. The Radiothermostat 3M-50 (in your link) says: FILTER - AIR FILTER ALERT - The ...


5

You'll have to find a unit that can match the required intake air flow of the furnace. Estimating required air flow. To estimate the required amount of air the furnace needs, you'll have to know what type of furnace you have, and how many BTUs the furnace is rated for. Once you have this information, you'll divide the furnaces rated BTU value by 10,000. ...


5

Since the purpose of replacing filters in the first place is to restore airflow which has been diminished by reduced filter porosity, it would be a better approach to use a differential sensor to monitor airflow, rather than a differential across the filter(s) In a ‘passive’ system with no blower control, the filters are simply replaced when the flow has ...


4

Usually the filter is mounted between all the return ducting and the furnace itself - potentially it is installed at a strange angle or covered up with tape or something. Here is a picture of mine, it's the darker colored piece the duct is attached to, with foil tape sealing it to the furnace housing.


4

Dirty filters not only make the HVAC equipment not last as long, but the low air flow makes them less energy efficient. A dirty furnace does not conduct heat into the air as well and the dirt sticks to the fan blades making it not last as long or spin as easily. There are two main types of air filters: The 1" thick ones that look like this: And the 6" ...


4

While I cant think of any DIY project, you may wish to call or research as to whether that particular filter vendor provides recycling. If you have any friends or family with a fireplace or wood stove I bet they burn well. Barring both of those, all I can suggest is to buy washable filters in the future. You will pay a higher premium up front but it should ...


3

You can use a pressure differential sensor like this one. Perhaps install a vacuum guage between each filter stage to measure the restriction of each filter. If you need to adjust the diferential and your skill level permits, you can build a circuit around this sensor. I figure a differential amplifier with a relay driver to a spst relay giving dry contacts ...


3

Talk to your HVAC service tech about installing a remote magnehelic gauge. They cost less $100 and you can probably install it yourself. When the fan runs it creates a vacum in the space between the filter and the fan. This pressure difference can be measured by the gauge. The higher the reading the dirtier the filter. You can experiment with how dirty you ...


3

The rule of thumb is every 3 months but it does depend on the filter and your air quality. And yes, if you don't keep the filter clean it will shorten the life of your unit and could cause other problems like a frozen coil (where the air handler coil freezes because there isn't enough airflow). I like to use the cheap air filters as they allow the best ...


3

Depends a bit on your furnace. If you have someone that services your furnace, ask them. I used to use a pleated filter with a high MERV value. The second time my furnace broke when it was well below 0 degrees, I spent some time talking with the service man. Apparently the type of furnace I have does not draw air through these filters as well as it ...


3

I have the same filter location as referenced by Steve Armstrong. There is no slot for the filter but it is just held in place over the return duct by a metal arm. Here is the opening between the return and the blower: And here is the filter in place over that opening with the metal arm holding it in place: I would not have known a filter was supposed ...


3

Typically your air filters are at the inlet of your furnace. The air should be moving into the furnace through your filters. Point the arrow into the wall/floor.


2

It depends on the filter. Go to Lowes or Home Depot and they will have a chart with the different filter qualities and the recommended length of time they can be in service. In general, the cheapest filters that cost only a couple of bucks have to be replaced once a month. As you go up to more expensive filters, you can replace them every 3 or 6 months. ...


2

The problem with the really cheap filters is that you really should replace them monthly. The slightly more expensive filters often only need to be replaced every 3 months or so, which in reality doesn't actually make them that much more expensive. I usually go with the cheapest 3 month filters, since I know I'm not going to get down there every month to ...


2

It could be that the air return system is blocked or insufficient, and cannot provide the proper air flow. Make sure your air return vents are not blocked by furniture or rugs, and possibly clean the return air system. You will also want to make sure the heat vents are open and clear of obstructions, if the warm air has nowhere to go it will not flow ...


2

if you refer to the "Microparticle Performance Rating", such as the difference between red Filtrete and purple Filtrete (and there are cheaper or more expensive then these 2), then I would say that it depends on: 1. do you have pets? 2. does anyone in your family get allergies, especially when you turn the heat/ac on? If yes to both, go with higher filter. ...


2

I don't know if this is common or not, but in our current house and our previous house, the filter is in the return vent inside the house. The vent grate has two little latches that allow it to swing out of the way, revealing the filter. To check if yours is like this, just look for the latches and/or look through the vent slots and see if you see a ...


2

This does not help you with your stockpile of used filters that you have right now, but for the future you could try switching to a biodegradable furnace filter (there's a few when you search Google) or you could try using a reusable furnace filter so that you do not produce as much waste. Keep in mind if you switch to a reusable filter then you need to ...


2

I recently went to change the filter in my new furnace and saw that the installed one said it was 16" x 25" x 5". I also couldn't find this size at my local bigbox stores. So I bought a 4" instead. The thing is, it fit perfectly. As it turns out, when I looked at the fine print on the old and new filters, their actual thickness was 4 3/8" in both cases. One ...


2

The thicker the filter, the more area can be created within the filter by folding the filter materials into baffles. This creates a very high efficiency filter, but I don't think I've ever seen one this thick stocked in a store. I'm sure you could resize the opening for a thinner filter, but if it was my choice, I'd order the thicker ones online. The same ...


2

Ends overlap Image Source Amazon


2

About any reasonably sized HEPA filter unit should do the job for you. There's huge price variations in the things, so looking for a unit w a decent fan motor, open cell foam pre-filter, and a low price is worthwhile. If you're do-it-yourself capable, they're not all that hard to make using a store-bought HEPA filter replacement filter, like this or similar, ...


2

If mold is an issue in your house I'm not sure a furnace filter is really going to help, even a HEPA filter as all it will do is filter the air passing through the filter; it won't do anything to prevent the mold spores from entering the air where they are growing. Generally the best solution to mold issues is to solve the moisture issue. If you have any ...


2

You'd be better off with a box fan as it has a large, square area that will support your filter media properly. It will need to be powerful enough to develop airflow despite the next addition. Not sure if you can find it, but we have here available electrostatic filter media by the roll. Cut several pieces large enough to cover the inlet side of the box ...


1

You are quite correct to note that pressure drop across an element within a dynamic fluid system is related to volumetric flow…this has certain implications. To return to your original question, “Can I sense filter replacement need based on pressure drop?” the short answer is, not really. This is for the reason you state, that such a differential pressure ...


1

That is very unusual, is there a chance your landloard changed it for you recently? Mine seems to get dirty almost instantly. Some things I'd check: The airflow direction of the filter is correct. You can verify this by feeling the air flow and comparing it to the arrow that is usually printed on the filter. Is the filter the correct size? If it's not ...



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