Does Opening Windows & Doors Help With COVID-19 ?

Data shows that having good indoor ventilation can reduce the chance of virus transmission. Armed with that knowledge, can something as simple as opening a door or a window help to fight COVID-19 and reduce coronavirus transmission indoors?

Recommended Air Changes Per Hour

Before we can say how effective opening windows really is, we need to know what our target for indoor ventilation is.

In a typical home, ventilation rates of 0.35–1 air changes per hour are recommended. For an office it’s approximately 2–3 air change per hour. However for areas with potentially high levels of viruses (like hospitals, or in a COVID context), the CDC recommends a ventilation rate of 6-12 air changes per hour.

So, can opening windows achieve these ventilation levels?

Open Windows to Increase Indoor Airflow

Data shows that opening windows in hospitals can improve air circulation by almost 20 times, from 1 air change per hour up to 20. That’s great!

However, that was only the case for ‘old-fashioned’ hospitals with large windows and doors. When scientists tested more modern hospitals with smaller windows, they found ventilation rates were half those of the older hospitals.

However, for both the modern and old-fashioned hospitals, opening the windows increased the air changes per hour above the 6-12ACH recommended by the CDC.

Opening Windows in Real World Homes

That’s for hospitals, which are designed with high ventilation in mind. But how about at home? Scientists from the US tested the effect of opening windows on the ventilation in a home in Cary, NC.

They found that opening windows almost doubled the air changes per hour throughout the house. From a baseline of 0.2ACH, air changes increased to 0.35ACH. That’s much lower than the 20 times increase found when opening windows in the old-fashioned hospitals. However, changes per hour just within the ASHRAE recommended range of 0.35 – 1.0 ACH.

If the goal is to reach the CDC’s recommended ventilation rate of 6 – 12 ACH, in an attempt to reduce COVID-19 transmission, then opening windows alone is not enough.

Opening Doors to Increase Indoor Airflow in Real World Homes

If windows don’t give a high enough air flow, then how about opening doors? The scientists in the US also studied this. The scientists simulated a real home by opening the door from 3 to 60 times per hour, as if people were entering and leaving the home. Here’s what they found:

No real change in ventilation was seen when the doors were opened fewer than 12 times per hour. Opening the door 12 times per hour increased the ventilation rate by about 40%. Opening the door every minute (60 times per hour) almost doubled the house’s ventilation rate.

That’s on par with opening the doubling in ventilation that occurred when opening windows. However, it’s still a long way off 6-12 air changes per hour the CDC recommends. If air changes in the order of 6-12 really are required, then the best ways to achieve this may be increasing the internal HVAC system, using a fan to blast air in/our of a window, or to install an air purifier.

Advantages & Disadvantages of Opening Windows & Doors

Opening doors and windows seem like simple, easy ways to increase a room’s ventilation. But there are other downsides. Here’s a summary of the advantages and disadvantages of opening windows and doors to increase ventilation:

Advantages:

• Quick & Easy – it’s built into (most) buildings!
• Can double the ventilation in most homes, or much more in places with bigger

Disadvantages:

• Difficult to control ventilation direction, although adding a fan may help.
• Difficult and potentially costly to control indoor temperature.
• Allows unfiltered outdoor air into the building [1]. Not great for places with outdoor air pollution.
• Not all buildings allow for windows to be opened

Bottom Line:

For buildings with large windows and high ceilings, opening windows can dramatically increase the indoor ventilation. However for more typical houses, offices and schools with smaller window, the improvement to ventilation is minimal. Other approaches such as using HVAC or running an air purifier may be more effective.

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Do Air Purifiers Work With the Window Open?

Will my air purifier still work if I have a window open? New test data from Smart Air finds that air purifiers can still meaningfully reduce particulate pollution in a room with a window cracked. Here’s what to know:

The Obvious: Air Purifiers Most Effective With Windows Closed

No one doubts that purifiers are most effective with the windows closed. That’s obvious. Real-world tests show that – even without an air purifier – simply keeping doors windows closed keeps particulate pollution levels at 50% the level of outdoor air.

But the more practical question is, if I have to keep a window open for some other reason, will running a purifier still work? Will it have a meaningful effect? For some people, keeping windows open is a necessity. You might want to keep your windows open to reduce chemicals such as VOCs and formaldehyde in your home or office. Others might want to keep a window ajar to ventilate out CO2.

The Test: Air Purifier vs. Open Window

Can we have it both ways – clean air AND open windows? CK from the Smart Air team put this question to the test by running the DIY Cannon air purifier Smart Air’s 12m 2 Beijing test lab six times with the window open and closed.

The effect on indoor air pollution levels of having your window open will be more prominent when outdoor air is hazardous, so CK chose two days when outdoor air pollution was bad (February 14th and 15th) for his tests. During these two days, Beijing’s AQI averaged 239 and 290 according to the US Embassy.

To keep the baseline level of pollution consistent across tests, CK opened the window to let in outdoor air (and outdoor air pollution) until it the particulate pollution was the same as outdoors. Then, CK turned the Cannon air purifier on high for 20 minutes. He ran three tests with the windows open and three tests with the window closed.

Results: Can You Use a Purifier with The Window Open?

With the window closed, the Cannon reduced particulate by an average of 90% after 20 minutes (blue lines). With the window open, the Cannon air purifier managed a 60% reduction (red lines).

The data shows that it’s clearly better to close the windows with running your air purifier. No shocker there!

But here’s the more interesting part: even with the windows open, it’s still possible to significantly reduce indoor particulate by turning on an air purifier.

Turning on the air purifier with the window open still reduced pollution levels by 60% within 20 minutes.

Bottom Line: Can I Turn on My Purifier and Open a Window? Will the Air Purifier Still Work?

Even with a window open, air purifiers can work decently and still meaningfully reduce particulate air pollution in the home – by 60% in 20 minutes in our tests. Obviously closing the windows is the most effective, but if you have to balance outdoor pollution against VOCs or CO2 indoors, it is possible to get some ventilation AND significantly reduce pollution.

Power Is Key

The best way to do this is to use a purifier that’s rated for a larger area than your room size. We do this in the Smart Air office by using the super-charged Smart Air Blast, which cleans up to 130m 2 . Here it is kicking butt in Beijing while the window is open.

How I Protect Myself

Smart Air is a certified B Corp committed to combating the myths big companies use to inflate the price of clean air.

Smart Air provides empirically backed, no-nonsense purifiers and masks, that remove the same particles as the big companies for a fraction of the cost. Only corporations benefit when clean air is a luxury.

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Case Studies & Reviews

See how Windsor has helped homeowners across the country.

Windsor Product Used: Pinnacle Wood Clad

Open Air Living

New Construction — Single Family Home

​Project Description

To create a high-end home with a prominent open air concept for maximum indoor/outdoor living.

Unique Requirements/Solutions

Built in the Pacific Palisades, a coastal Southern California community, this Cape Cod-style beach home boasts shake siding and white casement windows with wide exterior trim. The interior of the home is highlighted with painted white woodwork and an abundance of natural light created by 42 windows located throughout the home.

To create the open-air concept, builder CJ Rudolph integrated five multi-slide doors into the design. He opted for a 20′ wide stacking multi-slide door on the lower level, which opens up to an outdoor sitting area with an expansive covered patio and fireplace. To maximize floor space in the kitchen, Rudolph chose a four-panel pocketed multi-slide door that pushes all the way into the wall. This pocketed style of door allows for unobstructed views to the outdoors and provides a seamless transition to the pool patio, creating endless entertaining possibilities. The builder also installed four-panel pocketed multi-slide doors in both lower level guest rooms, which open up to the backyard deck and grassy area.

The highlight to this outdoor oasis is the exterior living space on the main floor sundeck, located off the upstairs sitting area and master suite. Both rooms feature pocketed multi-slide doors that offer unobstructed views of the stunning backyard when open. Imagine being able to bring the coastal sunshine indoors or feel the soft breezes of the Pacific Ocean from the comfort of your sofa.

aïr Windows and Doors

aïr is a contemporary windows and doors manufacturer that has been creating their stylish and sophisticated fixtures right here in the UK for the last 35 years. Working under the Trademark windows brand Everglade Windows Limited, from their inception, aïr have set out with the aim to stand out from the crowded marketplace of windows and doors manufacturers.

What Makes aïr Stand Out Exactly?

So, what does make them different from the rest? Well, aïr doors are not just any old door, and the difference between aïr doors and standard doors is more than just the aesthetics. Although, you’d be hard pushed to find better looking doors than aïr products, it’s the high standards for reliability, how easy they are to use and their performance overall that makes them popular options.

Our aïr Products

aïr understand the importance of providing a wide range of doors to really compete in the competitive market. That is why you will find entrance, bi fold, sliding and corner doors. All with the aïr touch of modernity and refinement. Perfect for contemporary homes, you have the choice of:

aïr Mod Flush Aluminium Casement Window

This casement window combines traditional design, advanced manufacturing and versatile aluminium for high levels of security and thermal efficiency to complement any type of build.

Providing an exclusive flush design on the outside giving a contemporary look, and with the cool, sleek aluminium finish, this window is truly a captivating masterpiece.

These stylish aluminium frames offer high-insulation, with U-Values from just 1.0W/m2K, watertight and wind resistance, these already well insulated windows, offer a triple glazing option also – clearly better thermal performance than the typical aluminium products on the market today.

And if you’re thinking that the aïr Mod Flush only performs on insulation, you would be wrong. This versatile window has enhanced security coming with PAS 24 certification and high-security reverse espag locking. Every window is fitted with the highest-grade stainless-steel hinges and locking handles giving you complete peace of mind that you and your home is secure.

The beauty of aluminium windows is that you can choose any RAL colour to suit your preference or internal décor. The windows are completed with a durable powder coated finish that is guaranteed against fading and loss of sheen for up to 25 years. The more traditional finishes such as white, black and anthracite grey are included in the price.

This truly unique window will not disappoint!

Aluminium Lift & Slide Doors

aïr is more than just a clever name when you consider their amazing aluminium Lift & Slide doors. Made to provide you with more stunning views and slimmer frames that don’t distract them. Not only do they have the easy-to-use 2-finger push and slide airglide mechanism, but they also have arguably the widest-spanned glazed panelling out there.

Visit our aïr Lift & Slide Doors page to find out more about these beautiful doors.

aïr Cornerless Sliding Doors

These are the perfect alternative to the traditional corner bi-fold doors we’ve all seen before. A major difference with these is that they don’t have the multiple small panels that you normally find in standard bi-fold corner doors. These have just two large panels of glass, nothing more, nothing less. Ideal for opening a darkened corner and bringing in some light.

They have an enviable reputation for their commitment to first-class service and quality and all their products are made on-site at their 65,000-sq-ft facility in London.