Holtop Eco-Smart ERV 2.5 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.

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.

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.

Yes – unused, undamaged filters can be returned within 30 days of delivery, and we cover the return shipping. Because private-label units built on a Holtop core rarely carry the Holtop name, the safest way to order is to measure the existing filter in millimetres (length, width, thickness) and compare it with our catalogue, or send us a photo of the unit's label and the old filter. We'll confirm the right size before you order, so a return is rarely needed.

Most Holtop-based residential units use a two-stage filter set: a coarser G4 or M5 class filter on the extract side and a finer F7/ePM1 class filter on the supply side. This is the same combination used by most European MVHR manufacturers, so replacement filters are easy to find as long as the dimensions are correct. If the unit is sold under a private-label brand, check the supply filter class on the old filter's frame or in the manual rather than assuming – some installers fit only G4 on both sides.

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.