A while back, my wife and I tried
on-demand planning to save oil (for hot water).
We would leave the boiler
off all the time during warm weather.
When we knew that we wanted to shower or wash laundry,
we would turn on the boiler ahead of time and let it run for 20-30 minutes.
Interestingly, my wife does almost all the laundry using cold water.
And, the dishwasher has it's own instant-water heater
sanitize-mode.
So, most of our planning involved bathing. Not too hard on the old brain..
During really hot weather, we would warm up the tank (76 gallons)
just about every morning. That burned some extra oil,
but, it was a Lot less than just letting the burner free-run.
I hate it when the boiler comes on at 1AM, when I'm least likely to want hot water!!
Planning ahead was a big success.. We just had to stay on the ball.
My wife liked the savings, but didn't like the planning.
Like when the weather would suddenly allow for a nice long bike ride,
but when we got home, ready for a shower.. Dang! Cold water!
I've been thinking of installing a timer that will keep the boiler off between 17:00 and 08:00.
It should be easy to do. I would install a 20A AC solid-state relay, in-line
with the hot-side and drive the DC control with an old programmable
thermostat.. (Low-power 5VDC wall-wart application).