My primary source of heating is an oil boiler and I really want to meter its consumption.

I can't use a Watchman or Apollo oil gauge to assist as the plastic tank has complex geometry - I can tell when it's full, exactly half full or empty but haven't a clue about in between.

At present I am assessing the consumption based on observed burner run times during start-up / 1st hour and for the maintained hours. This works reasonably well for the moment, as long as I don't adjust the set temperature or change the timer settings.

I have researched the oil meters on the market and am not prepared to pay around £250-£300 as this is the cost of my annual oil use. There are cheaper delivery flow meters on the market but these arenot accurate below 10 litres/min and my burner flow rate is 1.92 litres/hour.

I was thinking of measuring the burner hours run or the electical energy used. As the burner uses 103 Watts of electical energy to produce 19.2 kW of thermal and it is either 100% on or off, it's a straightforward calculation. For the latter option I have an Owl monitor which I can try, but I have found it to be pretty inaccurate at low energy use and it only seems to accept a single sensor, so electricity and oil could not be monitored.

Any ideas as to how this could be done for a budget of £50 to £60?

Posted By: SteamyTeaCan you wire in a plug in energy monitor to the oil pump circuit.

Tried that (used it to measure the Wattage) but it resets to zero each time the timeclock goes off.

The CurrentCost with multiple sensors could work, especially as I would be wanting to measure ASHP electrical consumption down the line.

<blockquote><cite>Posted By: GaryB</cite>I have researched the oil meters on the market and am not prepared to pay around £250-£300 as this is the cost of my annual oil use.</blockquote> I find myself wondering if it's worth the cost of monitoring at the daily usage scale, if you're only using £200 -£300 pa why not monitor at the annual scale, ie. Set an annual oil usage reduction target and see how you fare with that.

How easy was it to get all the parts and what was the cost?
Thinking of going that route for Mk2 for my project.

Posted By: TriassicI find myself wondering if it's worth the cost of monitoring at the daily usage scale, if you're only using £200 -£300 pa why not monitor at the annual scale,

That's approaching a tonne of COâ‚‚ emissions so worth paying some attention to.

Also, measuring at higher temporal resolution allows better assessment of overall house performance - comparison against outside temperature, etc.

Thanks Gordon
Shall look into that if I get the next lot of funding.

You have probably guessed by now that none of us like paying much for things

Those CT meters like Owl etc are generally set for full scale at something like 50 to 100 amps.
Your 0.4 amp boiler consumption sis less than 1% of full range so it is not surprising if numbers are not very reliable.

But it is fairly easy to adjust the sensitivity of a CT sensor. The sensor produces an (AC) electrical current. You just increase the value of the burden resistor so that the same current produces a larger voltage.

Thanks everyone for the suggestions - I'll look into them all over the next few days.

I like the simplicity of the battery back-up plug-in meters suggested by Ed, I'll probably get one to start with.

In the longer term I'm interested in an all-in solution which can monitor electrical, water temperatures (DHW and heating flow) and PV output (a future aspiration). The most difficult to find it seems is the water temperature monitoring.

The most comprehensive system I have found is by MeasureMyEnergy, but it is rather pricey.