Improve your (modern) boiler efficiency

PaulDG

Basically, turn the boiler thermostat down.  (Not the room thermostat, the one on the actual boiler).  Modern, condensing boilers are designed to run at lower temperatures but they're often not set up properly by installers.  (Government data shows over 90% are incorrect.)

I'm not allowed to post links, apparently. But "Heat Geeks" has a short video on YouTube if you search for "Heat Geeks Pay less for heating" which explains it all.

Mstty

https://youtu.be/lu0k8A7K2kY

The_Fat_Controller

If you turn down the boiler output too far your home will never get to the required temperature or if it does it will take much longer than expected.

As with most things in life it's a compromise, fine to get the boiler condensing more of the time but suffering the consequences of not being warm enough in good time.

Ultrasonic

There are potential savings to be made here but not huge ones. Think ballpark 5%.

BUFF

There are long threads on MSE forums about this already. How much you will save depends upon where you start from & comes with caveats e.g. radiator sizing and/or time to heat to required temp.
Turning your room stat down 1C or more will probably do as much/more.

Combine them for max effect.

Zandoni

You also have to consider that the boiler will use more electricity because it will be running for longer periods.

BUFF

True but imo for the "average 12000kWh p.a. user" or greater the gas saving still noticeably outweighs the additional electricity (in my case I estimate that it does cut  probably ~£2/month off the gas saving at current SVT rate).
& that's on a 13 year old boiler which predates them being mandated to have higher efficiency circulating pumps fitted (so a truly modern boiler would use even less).

I definitely can see some people saying that the potential savings aren't worth the hassle though. Of course, for those with compatible modern load/weather compensating controls it should all be done automatically.