There are several domestic products on the market which imply they benefit people with asthma, either directly or by association. We are not aware of studies which consistently show clinical benefits of individual products, such as preventing the disease, improving the symptoms, or reducing the risk of exacerbations. In a few cases there may be single studies which show a benefit, but there are also other similar studies where such benefits did not occur, and so the findings are inconsistent.
This is not to say that the products do not perform as they are intended to from a technical perspective. Vacuum cleaners do pick up dust from a floor, washing machines do clean clothes, the air coming out of an air filter is cleaner than the air going in, some carpets hold less dust than other types of carpets etc. However when individual products are used in the normal houses over time, they have not been shown to consistently provide clinical improvements in asthma.
This is also not to say that exposure to domestic allergens such as those from cats, dogs, cockroaches, dust mites or fungi are never important in asthma. It is likely they can be important for some people, at some time, but not for all people with asthma who are allergic, and not at all times. At present we do not know enough about the different risks and patterns of allergen exposure, how to identify the subset of allergic people who might benefit from reduced exposure, and how to use the different products in combination to obtain a possible clinical benefit.
More research is needed in this area.