For people with dust mite allergies or asthma, choosing the right duvet is important, because bedding can be a major source of dust mites and their allergen-filled dust.

This is Blog 2 in this series on duvet inners, and it compares fabrics in terms of dust-mite care, weight & feel & price. Blog 1 looks into some of the Scientific research.

Table of Contents:

1. House Dust Mite Allergy (HDM)-why consider it with bedding purchases 
2. Research Summary to help select bedding 
3. Fabrics In NZ Duvet Inners – Key Features and Benefits for People with HDM        Allergy   - including a summary table 

• Silk
• Alpaca 
• Wool, 
• Down & Feather 
• Tencel
• Synthetic Microfibre

4. Other factors to be aware of
5. A note on Chemical Sensitivity 
6. The role of a Dust Mite Barrier Duvet Cover 

1.  House Dust Mite Allergy - Why consider it for duvet inners? 

For those of you who are unfamiliar with Dust Mites and dust mite allergy – here is an outline of what it is about.

House Dust Mites (HDM) are tiny natural creatures that live in abundance in house dust. They feed on organic materials, such as human skin which is shed daily in our homes. Dust mites live in warm, moist environments such as beds and soft furnishings.

Dust mites are a major contributor to allergies, asthma, rhinitis, atopic dermatitis or eczema. They excrete numerous allergens into the environment.  Their faeces get into the air easily and can provoke a strong allergic response when inhaled.¹

Scientific research recommends dust mite allergen avoidance for anyone allergic to dust mites, or who has Asthma.²  so using the factors shown to be important in reducing exposure to dust-mites, can help us select better bedding. 

2. Research summary to help select bedding

In our previous blog, "The Best Duvets for Dust Mite Allergy - THE SCIENCE", we talked about how scientific research over the years has tested and changed views over what the best duvet fabrics are for people with HDM allergy.

Key findings were: 

• Micro-fibre is no longer recommended above natural fabrics as it houses as much, if not more DER p1 allergen dust and as other fabrics such as Down.
• Washability is considered important as it is a low cost, low chemical method of reducing allergen and dust that can accumulate in duvets. It is important to note that low temperature washing  (below 55℃) will not kill the mites themselves, so airing duvets in sunlight, or using a dryer to reduce humidity in a duvet will help achieve both goals.  
• Duvets can also be dry cleaned to kills mites (this doesn't remove dust).
• Breathable fabrics aid body temperature regulation.
• Moisture wicking fabrics help pull moisture away from the sleeper and the bed, creating a dryer bed that is more resistant to bacteria, moulds and mites. 
• Duvet barrier covers such as a MiteGuard Duvet Cover can  be used to protect the duvet from becoming a source of HDM.

Other factors to consider when purchasing a duvet – especially if you suffer from allergies are:

• Warmth rating of the duvet
• Weight of the duvet 
• How it may feel against your skin

These factors all help to avoid HDM allergen and get a better sleep, so how do you compare fabrics?  

3.  Fabrics In NZ Duvet Inners – Key Features & Benefits for People with Allergy  

Research from both the fibre industry and medical science on the qualities that promote good sleep, and what features are best for allergy avoidance.  The following fabrics/fibres used for Duvet inners in NZ are discussed below then condensed into a summary table:

Silk 

Silk has been used for centuries as a strong, lightweight fabric.

Advantages 

• Silk fibres offer excellent breathability and moisture absorption (1.5 times that of cotton). Silk can absorb sweat and dissipate it from the sleeper efficiently. This keeps you and your bedding dryer – and helps avoid dust mites.
• Silk is soft. It is good at retaining warmth against your skin whilst feeling cool, so is recommended for hot sleepers, and for those with sensitive, dry or allergenic skin. 
• Silk is hypoallergenic, naturally anti-microbial and dust-mites struggle to live in it. 
• Silk is very strong and warm for its weight, so a silk duvet will be lighter than other fabrics for the same warmth.   

Disadvantages 

• Silk quilts usually require handwashing or dry-cleaning.   
• Silk is expensive, can stain easily and has poor resistance to water.  
• Check the quality - there have been incidents of silk waste being used to make bedding and that can produce an allergic asthmatic reaction in a small number of users.³ 

Alpaca

Alpaca fibre  

Alpaca fibre is a natural lightweight fibre known for its excellent insulation. Fibres are sourced in NZ and from overseas.

Advantages:

• Alpaca fibres are hypoallergenic and resistant to dust mites, mould and mildew making Alpaca duvets a good choice for those allergic to HDM.  
• Alpaca fibre is light with excellent insulation qualities, making these duvets very warm for weight. For a winter rated duvet, an alpaca duvet would be about 25% lighter and less bulky than a wool, Tencel or cotton.   
• Alpaca fleece is soft and does not have lanolin, which can be a good alternative for those with lanolin sensitivity or sensitive skin.    
• Alpaca is naturally fire resistant. 
• Alpaca fibres breathe which can help a sleeper to regulate body temperature.
• NZ Farmed animals are eco-friendly and ethically grown, and the fibre is biodegradable.⁴

Disadvantages 

• Alpaca fibre duvets usually require handwashing or dry-cleaning
• They are in the more expensive range of duvet inners. 

Wool

 

Wool was not promoted as a dust-mite friendly fabric because it was thought to pool dust, be difficult to hot wash - and coarser wool fibres created a rough feel for sensitive skin. Modern research shows that today’s wool can be considered.

Advantages 

• Wool can absorb up to 30% of its weight in water, which means it can draw perspiration away from your skin. Moisture then evaporates through the fibre into the air, leaving your bedding drier, and more resistant to mould, fungus, bacteria and dust mites.
• Wool maintains ideal moisture levels, even for differing body temperatures.
• Wool is hypoallergenic and breathable. The natural crimp in wool fibre traps tiny pockets of air - allowing the fabric to breathe freely and for the wool to be warm in winter and cool in summer. 
• A keratin-based protein chain creates spring that gives wool flexibility, elasticity, and resilience. The keratin also means wool is naturally fire-retardant.⁵
• Wool is a heavier option than silk, alpaca and down. This means that of the duvets with a similar warmth rating, wool will be heavier. Some sleepers, such as those with anxiety, may prefer a weighted feeling in their bedding, but for those who want a light, airy feel, another fabric might be better.
• Wool duvets comes in a range of prices and grades - NZ wool in particular, is known for its quality, and a range of wool blend duvets are also available. 

Disadvantages 

• Only some wool duvets can be washed and most cannot be hot-washed, so they need regular airing in sunlight (UV) or dry cleaning to kill all dust-mites. A (low temperature) dryer can also be used to reduce humidity in a  wool duvet. 
• Although wool allergy has been disputed,  the lanolin in wool has been thought to associated with some skin intolerance. 

Down and Feather

  

Feathers and Down has been used for centuries throughout the world as a light weight, very warm insulator. Ducks and Geese are the most common sources of the feathers/down. 

Like Wool, Down was thought to have a relatively high risk of dust and allergen compared to other duvet fabrics so was not recommended. More recent research has found that there was less house dust allergen in feather duvets than in synthetic microfibre, and changes in manufacturing processes are now making quality down duvet inners an option to consider.

Advantages:

• Down/feather is a light, warm insulator. 
• Most modern Down & feather duvet fill is washed and dried at over 100° C, which denatures Der p 1 ( dust mite allergen) and kills the dust mites, making down duvet inners a viable bedding option even for those sensitised to Dust mites.
• Down duvet inners are breathable.   
• Feathers are used to add structure to the finer Down. A higher ratio of down to feathers creates a warmer, lighter and “puffier” duvet. 
• Quality down duvet inners need a “down proof” encasement fabric to  stop feathers poking holes through the quilt. This also helps create a barrier for dust-mites. Older outer fabrics were even waxed, which reduced breathability, but waxing is unlikely on modern down duvet encasements. 
• Some down duvets can be tumble dried, which can kill mites and reduce humidity ( less humid = less hospitable to mites). 

For Down and feather duvet inners some of the things you should check: 

• the ratio of feather to down (more down is warmer & more expensive) 
• the quality of the outer encasement 
• Whether the down was pre-washed 
• Certifications such as Responsible Down Standard (RDS) to establish ethical sourcing and or quality of the down and feathers.     
• Where it is made. There are NZ made options available.   

Disadvantages 

• Down will break apart and form very fine dust over time.   
• Some down duvet inners are washable, but most recommend dry cleaning. 
• Quality Down quilts can be expensive. 
• Down is less moisture resistant. 

Tencel 

Tencel® is semi-synthetic textile made from wood pulp that is chemically processed into thread. The wood fibre used is usually eucalyptus, bamboo or beech. The fibres trademarked with Tencel are sometimes call Lyocell or Modal.      

Advantages

• Tencel has a great ability to absorb moisture and wick it away from the body.  
• Industry research reports that Tencel holds 2000 times less bacteria than synthetics. With its moisture wicking properties and resistance to bacteria, it can be classified as hypoallergenic.  
• Tencel is soft, silky and cool to feel. (Our “tactile” son LOVES the feel of Tencel). Whilst Tencel duvets are heavier in weight than alpaca or down,  the cool feel can be helpful for hot sleepers and for those with sensitive or allergenic skin. 
• TENCEL® products can be machine washed and tumble-dried, (low temperatures only) so they are relatively easy care. This can make them a good choice for children, teenagers and those with HDM allergy.   

Disadvantages 

• Tencel® can be susceptible to mildew, so regular airing is recommended.
• Tencel can be expensive – although blends with wool are mid priced. 
• Copies  without the Tencel trademark sign, may not be able to make the same claims, so again checking the source and certifications of the duvet is recommended. 

Synthetic Fibre Duvets 

Synthetic duvet inners can be made from hollow fill fibres or microfiber fabrics.  Hollow fill fiber material has a space between the fibre knots, giving them a level of breathability, whilst microfibres are made from very tightly woven fibres.  Microfibres fabrics are created from a petrochemical base.  

Advantages 

• They are usually machine washable and can be tumble dried on low -moderate temperatures, which means you can wash HDM allergen dust from the duvet inners. Hollow-fill is less durable than microfiber.  They will still need airing in UV sunlight or higher temp washing to kill mites. 
• Synthetic duvets are cheaper than most other duvet types which makes them great for those on a tight budget. 
• Synthetics may have chemical “anti-allergy” treatments added, which can help resist HDM. The longevity of the treatment with frequent washing is not always known.

Disadvantages 

• Microfibre was promoted as a duvet of choice for allergy sufferers because they could be easily washed. A scientific study has since shown that synthetic duvets contain significantly higher levels of Der p 1 than even feather duvets - probably due to the greater pore size in the encasement material. For HDM sensitive people Microfibre duvets should be washed frequently. 
• Microfiber absorbs heat – so it can become very warm and is not generally as breathable as natural fabrics.
• Synthetic duvets more easily absorb body oils and dirt from sweat than many natural fabrics, so need washing more frequently. 
• Cheaper synthetic materials may pill and may create static electricity.
• They can compress and lose insulation capacity more easily than duvets made from natural fibres. They have a shorter life.   
• Synthetic fabric are made from petrochemicals, so are less sustainable than natural fabrics and will not be biodegradable at their end of life.

Duvet Summary table

 

*Some treated with anti-dust mite, bacterial and fungal treatments

#If the down is pre-washed at high temperature before manufacturing.

4. Other factors to consider when buying your duvet 

Size:

Usually people buy a duvet to match their mattress size. If you would like the edges of your duvet to hang over the sides of your bed, or to give you extra wiggle room if sharing with a partner – consider buying the next size up, or even 2 separate duvets that meet your different needs.   

Duvet Weight:

What feel do you like for your bed? Light and cosy – or heavier and snug?   Heavier weight duvets (e.g. wool) can give people a feeling of security, whereas being able to easily move a lighter duvet around (e.g. down/alpaca), may be important for someone who is restless or feels their body temperature changes frequently during sleep.

Duvet warmth rating 

Do you want your duvet to work across seasons or do you need it to have a specific seasonal profile? Loft, tog and gsm are all terms used to describe a duvet weight. 

• High loft is usually 400gsm or higher and is about 2-3 blankets. It is the warmer weight.    
• Light loft is usually less than 200-300gsm and is about 1-2 blankets. 
• “Combo” duvets have a combination of two different weights that can be used separately for warmer times of year, or put together for the cold winter months.
• Tog ratings go from 1 tog (the coolest) to 15 tog (the warmest). For summer, a 1-7 tog duvet will usually be fine, whereas 10.5 tog or above is winter weight.

5. A Note on Chemical Sensitivity 

There are several processing steps for creating fibres from their raw material and the production of all fabrics involves chemicals.  Some suppliers use organic chemicals and these are usually certified as organic, although small suppliers may not always pay for the certification.  Consumer laws in NZ mean that the end product needs to be safe for use and fit for purpose, but if you have concerns over a particular chemical sensitivity, it would be best to contact the manufacturer of the duvet you are interested in. 

6. The role of a Dust Mite Barrier Duvet Cover  

Even when you have a hypoallergenic fabric – if skin cells pool in cracks and gaps or between fabric pores, then over time dust-mites and allergen builds up. HDM levels found in international studies of duvet covers are still high. Advice for HDM sensitized people is to use barrier covers on all bedding items.

Using a MiteGuard duvet cover, gives you a greater choice of duvet inner and that makes care of the inner easier. Rather than having to wash the duvet,  the MiteGuard barrier cover gets washed instead. The barrier cover is designed to be hot washed, so mites can be killed. The inner can be aired in the sun, vacuumed and shaken outside to reduce dust and mites each season.

Disadvantages of a barrier cover 

• The duvet barrier cover will add a layer of warmth which can be a plus in winter, but not as good in summer or for hot sleepers.
• Whilst the covers are a breathable cotton, the tight weave may still reduce the overall breathability of your duvet, so for Summer, a washable light duvet may be an alternative option.  

For more on the how these factors relate to different fabric types – see “ The Best Duvets for Dust Mite Allergy - THE SCIENCE - Blog 1 ”

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• ¹ House Dust Mites -Fact Sheet prepared by the Asthma and Respiratory Foundation NZ-2010
• ² Hewitt CR, Brown AP, Hart BJ, Pritchard DI. A major house dust mite allergen disrupts the immunoglobulin E network by selectively cleaving CD23: innate protection by antiproteases. J Exp Med. 1995 Nov 1;182(5):1537-44. doi: 10.1084/jem.182.5.1537. PMID: 7595223; PMCID: PMC2192194.
• ³ Silk waste--a further allergen in the bedroom – Sashina, Elena S., and Olga I. Yakovleva. 2023. "The Current State and Prospects of Recycling Silk Industry Waste into Nonwoven Materials" Fibers 11, no. 6: 56
• 4 Alpaca association of NZ