10 Questions About HEPA Air Purifiers That You Need To Know

I summed up the ten most commonly asked questions about HEPA Air Purifiers to help you decide the best pick for you. Let’s read this valuable article.

  1. Why do you need an air purifier?

The easy answer is to protect you. HEPA air purifier can kill airborne allergens like dust, mites, mold, spores, and pet dander. Air purifiers in your home will hugely improve your health. It punches two ducks at once. First is that you limit respiratory ailments from happening. Most allergies and asthma are caused by indoor pollution. Therefore by owning one at home, expect that your family members will be saved from having these.

The second is control. It is critical to remove any inflammation sources and triggers for people who already have existing allergies or respiratory conditions like COPD and asthma, including airborne pollutants. You should know your need first before choosing to buy one.

  1. What is CADR?

CADR (The Clean Air Delivery Rate) of an air purifier is a numerical amount allocated to an air purifier based on objective tests performed for the Association of Home Appliance Manufacturers (or AHAM). This denotes how much clean air the purifier can bring to a room in cubic feet per minute. The higher the CADR, the better the filtering capacity of the purifier.

  1. How frequently do I need to change the filters, and when would I know if it’s time to change?

First, you have to know that True-HEPA filters aren’t washable or cleanable. You must replace them with new ones from time to time. And how often depends on every filter individually. Usually, HEPA filters must be changed once a year, sometimes more often, sometimes less often. This information is stated in the user’s manual. Now, most of the HEPA air purifiers have filters change indicator lights, which will show when it’s time to replace the filter.

Extra tip. Usually, customers complain because they’ve bought a HEPA air purifier at an affordable price, but expensive air filters are killing them. This is very important to know because HEPA air filters are pretty expensive. You wouldn’t want to spend your money purchasing filters again and again. If you are buying one, do not hesitate to review first how much the unit’s replacement filters are. Read my costs of air purifiers post to read more.

  1. Can one air purifier clean my whole house?

    Aprilaire 1870F 130-pint Air purifier

In theory, yes, there are such units as Aprilaire 5000, Airpura models V600, C600, R600, T600, Phoenix Guardian Air scrubber, etc. But even they have a maximum capacity, and if you are close to them, then the unit will not work as great as possible. Also, these units will have to work with maximum power to handle your whole house, and in this state, they will be really loud and cost-ineffective.

What can I suggest? When purchasing an air purifier, I recommend checking your room’s air quality first and recognize which rooms are mostly used and crowded. For example, you spend about 8 hours in the bedroom per day, and then you should focus on cleaning the air there.

  1. Where should I install my air purifier?

For you to understand the answer to this, you should first answer two questions. Where do I stay longer? What am I allergic to?  If you stay mostly in your bedroom, but the air purifier there. This way, you are guaranteed to have maximum clean air for the longest time possible. Second, if you’re allergic to pet dander, put the air purifier in the place where your pets regularly stay. If you’re allergic to dust, find the place where dust usually grows in your home.

  1. How long should I let my air purifier run?

The best is to let them run all the time because the air is being cleaned only when air purifiers are working. I understand that it’s impossible and could be costly, so I recommend running it about 8-10 hours per day.

  1. Would there be an increase in my electric bill?

Yes, but not that much as you may be imagined. It depends on how many watts the air purifier has and how often it will work. Common air purifiers consume about 50 to 200 watts. If you run an air purifier 8 hours per day, it will be about $2 – $7 per month. More about energy consumption read in my article Costs of Air Purifiers you have to know before buying one.

  1. How much noise does it make, and will I ever sleep with it ON?

This is a tricky question because every person has a different sound perception. One may say loud, while others can easily sleep in the same noise. I bet you have read customers’ complaints about noisy HEPA air purifiers.

All air purifiers make noise. I suggest you choose the unit with more than three fan speeds because then you will be able to select between noisier and quieter fan speeds. With the lowest fan speed, an air purifier can be as quiet as the average whisper, with the highest fan speed as noisy as a fan and vacuum cleaner.

Will you ever sleep with it on? Most of the people will.

I have ideas you can do to decrease the effect of the noise an air purifier makes. Read more about them in my air purifier buying guide.

  1. How much will it really cost me?

This question I have already answered above. There are two main costs – filters and electric bills. When buying an air purifier, be sure to take the price and regularity of future filter replacements into consideration. The average filter life of all included filters is usually listed in the specifications of the goods.

  1. How will I know which is the best HEPA air purifier?

It all depends on your needs. There are many things to consider. First is that you should know what you need. It would help if you understood the allergens to see the potential units that can address it accurately. Determine the size you need, features, noise level, CADR, read reviews, and check comparisons before purchasing.

Feel free to start with everything you can find on my website.

Other Useful Resources:

Hamilton Beach 04383A True HEPA Air Purifier Review

Hamilton Beach 04383A is one of the best-sold air purifiers. The price is under $50, which is really cheap for 160 square feet (15m) size room. Does it really work? Read more below. Pluses: Minuses: Design, size, placement The Hamilton Beach 04383A is a very small air purifier. It looks like a speaker in both – […]

Winix PlasmaWave 5300 Review

Winix PlasmaWave 5300 Air Cleaner Review

The Winix WAC5300 is a great air cleaner for rooms up to 350 square feet (32.5m2) and costs between $130 and $180. Very good price for such size space. The Winix WAC5300 contains a 99.97% efficient True-HEPA Filter, Odor Control Carbon Pre-Filters, and PlasmaWave Technology. Pluses: Minuses: Design, size, placement The Winix Plasmawave 5300 air […]

Best Air Purifier for Mold Removal

Best Air Purifier for Mold Removal

Having mold or mildew growth in your home could be unsightly as well as dangerous. Such occurrences are usually the result of humid air and bacteria, along with any spores that may have wandered into the interior of your home. The result could be growths that also reduce the value of your house along with […]


My name is Ryan. I have had a hard time dealing with my allergies. Happily, I found that an air purifier was effective to ease my allergy symptoms. I spent a lot of time researching the best air purifier. I know how hard it can be to find the suitable one. During the reading period, I also read a lot about humidifiers and dehumidifiers. I learned the mechanisms behind the technologies as well as the manufacturers and organizations within the industry. I now feel convinced that I have built a guide that shows you all you need to know about air purifiers, humidifiers, and dehumidifiers. So I came up with the idea of creating this website.

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