Holtop XHBQ-D5 filters

Holtop is one of the world's largest manufacturers of heat exchanger cores and OEM components for MVHR units of all kinds, and its parts are used in many other brands' or regional manufacturers' units sold under an entirely different name. If you see a Holtop part number on your unit's core, fan block, or filter holder, even though the housing is labelled with a different brand, our Holtop filter listing is very likely to be an exact match.

No – using a correctly sized filter that matches your unit's Holtop filtration class specification does not affect the warranty on the heat exchanger core or fan block, since that warranty covers manufacturing defects, not which brand of filter you use. What matters almost always is the correct size and filtration class, not the specific filter brand on the box.

Many Holtop-based unit housings can accept a denser F9 or HEPA-class filter on the supply air side instead of the standard F7 – this retains finer allergen particles. Because denser filter material increases resistance to airflow, before upgrading it's worth checking your unit's fan capacity or technical manual, especially on smaller residential models, so that the unit doesn't start running noticeably noisier.

Remove the filter and measure three dimensions in millimetres:

• length
• width
• thickness

Holtop manufactures its filter holders to a fairly standardised set of sizes across its entire product line, so an exact dimensional match will almost always help you find the right replacement, even if the specific model name can't be determined.

The same rule applies as for most residential MVHR units: check the filters every 3 months and replace them at least every 6 months. Since private-label units built on a Holtop core often have no filter reminder, or one that isn't calibrated to your conditions, a fixed calendar interval is the safest approach. Homes near busy roads, with pets or with allergy sufferers should lean towards 3 months, and during the heating season or the spring pollen season it's worth taking a look at the filters even earlier.

Three things help us identify the right filter quickly:

• a photo of the data plate or sticker on the unit, even if it shows a private-label brand rather than Holtop
• the dimensions of the old filter in millimetres – length, width and thickness
• the filter class printed on the old filter's frame, if visible (e.g. G4, M5, F7)

With those details we can match the filter to the Holtop core inside your unit, regardless of the brand name on the outside, and confirm the correct size before you order.