Before fitting a retrofit emission control device (RECD) to a diesel generator, most owners ask about RECD fuel consumption and the engine warranty. Will it raise my diesel bill, and will it affect my warranty? A certified, correctly sized RECD should keep fuel use close to normal, and it does not automatically void a warranty. Here is what to check before you decide.
At a glance
Fuel use: low back-pressure designs keep fuel use close to normal.
Back-pressure: high back-pressure can strain the engine, so ask for the device's rating.
Warranty: check your engine maker's terms and use a certified device.
Does an RECD increase fuel consumption?
Any device in the exhaust adds some resistance to gas flow, called back-pressure. Low back-pressure designs keep fuel use close to normal, because the engine does not have to work harder to push exhaust out. Problems start with an undersized or poorly installed unit. Load, exhaust condition and maintenance also play a part. The most reliable test is your own: record litres used and kWh generated for a few weeks before and after installation.
Why back-pressure matters
High back-pressure can strain the engine and may mean higher fuel use, more heat or reduced output. Engine makers set a maximum exhaust back-pressure for each engine. Ask the vendor for the device's back-pressure rating and compare it with that limit. Four things influence it:
Design: media-based units can load up with soot over time. Filterless designs, such as an electrostatic precipitator, have no filter to clog.
Sizing: the device must match the engine's exhaust flow, not just its kVA rating.
Installation: pipe length and bends in the exhaust line matter.
Maintenance: cleaning on schedule keeps performance stable.
Does an RECD void the engine warranty?
Not automatically. Warranty terms are set by the engine or genset maker and vary by brand. Two points help:
Boards in several states target DG sets more than five years old, and many of those are already outside a standard warranty.
If your set is under warranty or an OEM service contract, ask the maker for its position in writing before installation.
A device certified under CPCB's RECD procedure is your strongest starting point. That procedure also does not allow an increase in the original set's noise level.
Five checks before you buy
Ask for the ARAI or ICAT certificate covering your DG set's capacity.
Ask for the back-pressure rating and compare it with your engine maker's limit.
If the set is under warranty, get the OEM's position in writing.
Choose a CPCB-listed vendor and keep installation and commissioning records.
Follow the AMC schedule and keep a before-and-after fuel log.
FAQs
Will an RECD reduce my DG set's power output?
A certified RECD should not materially cut output if back-pressure stays within the engine's limit. Ask your vendor for the test data.
Can I fit an RECD on any diesel generator?
Only on sets within the capacity range on the device's certificate. Check your nameplate in kW (kVA x 0.8).
Does an RECD need regular maintenance?
Yes. Regular servicing under an AMC keeps back-pressure and emission performance within limits.
Talk to Novorbis about RECD for your DG set. Novorbis Itus is on the CPCB RECD vendor list (as of 30-06-2026). Share your DG set's capacity, make and age, and we will confirm the right device and what to check with your engine maker.
Talk to Novorbis about RECD for your DG set.
