Holtop Eco-Smart ERV 2.5 filters

The Holtop filter sets we stock — for the Eco-Smart ERV 2.5, Eco-Smart ERV 3.5 and XHBQ-D5 — are G3+G3: a coarse G3 filter on both the supply and extract side that protects the heat exchanger core from dust. They are made in our house brand to the original dimensions.

Holtop is one of the largest OEM manufacturers of heat recovery cores and units globally, and its components are used inside many private-label and regional MVHR brands sold under different names. If your unit's core or fan assembly carries a Holtop part number even though the outer casing shows another brand, our Holtop filter listings will likely be the correct match.

Remove the filter and measure three dimensions in millimetres:

• Length
• Width
• Depth

Holtop's filter housings are produced in a relatively standardised set of sizes across their unit range, so an exact size match will almost always identify the correct replacement even without the specific model name.

No — using a correctly sized filter matching your unit's Holtop-spec filtration class doesn't affect the warranty on the heat exchanger core or fan assembly, since those warranties cover manufacturing defects rather than which filter brand you use. The requirement is almost always about correct sizing and filter class, not the label on the box.

Check the filters every 3 months and replace them at least every 6 months. Coarse G3 filters hold a lot of dust before airflow drops, so don't wait for them to look completely grey — if the unit gets louder or the air feels stuffier, change the set straight away. Vacuuming or washing G3 filters is not a substitute for replacement, as it damages the media.

Because Holtop builds ventilation units that a number of European suppliers sell under their own names, so a unit badged by a Belgian or Dutch supplier can have a Holtop core and Holtop filter dimensions inside. That is normal and says nothing bad about the unit. To find the right filter, work from the physical evidence rather than the badge: the dimensions of the old filter in millimetres, the filter class printed on its frame if it is still legible, and a photo of the type plate — in whichever language it happens to be printed. With those we can match the filter regardless of which company sold the unit.