Can kerosene and gas oil be mixed for domestic heating?

Yes, kerosene and gas oil can technically be mixed, but it is not recommended for domestic heating systems in the UK — especially when efficiency, safety, and warranty protection matter.

For most UK homes, boilers are specifically designed to run on 28-second kerosene (heating oil). Gas oil (35-second oil), commonly used for commercial or agricultural purposes, burns differently and can lead to:

Poor combustion performance

Increased soot build-up

Higher maintenance costs

Potential damage to your boiler

Voided manufacturer warranties

Even small mixing ratiOS can affect burner settings and efficiency.

At Compass Energy, we always advise using the correct fuel specified by your boiler manufacturer. If you’ve accidentally mixed fuels or are unsure what’s in your tank, it’s best to seek professional guidance before running your heating system.

For reliable domestic heating, stick with the right fuel — it protects your boiler, your home, and your long-term energy costs.