Solar diverter - flawed return on investment calculations

iotum

Qyburn said:

iotum said:

My generation is 10% greater than predicted, I'm consuming 60% of what I generate and electricity prices are way higher than the assumed inflation rate. Yet in spite of all of that, I've saved 10% less than the provided estimate. 

Out of interest, what was the incorrect assumption in the estimate?

Assumed inflation is 3% but for electricity and heating fuel inflation they assume 7%. 

Niv

Screwdriva said:

Niv said:

Screwdriva said:

Batteries still do make sense if you have a heat pump or drive alot in an EV but for the average household, Octopus Flux torpedoed any remaining financial rationale for a battery. 

The hot water diverter's best days are behind it I'm afraid, unless you're using alot of oil to heat hot water. 

My latest oil delivery saw oil priced at 60p / litre so ~ 6p per KW - even with oil heating a solar diverter is not worth it currently

True but factor in a heat pump with a SCOP of 3.5 powered by PV and the equation changes a bit.

Personally, I find the inconvenience of oil to be something I wouldn’t want to live with. 

I agree. I should clarify, I was referring to 'money saving' only. In reality I think I will keep the water being heated by solar for the convivence factor and a way to make the oil last a bit longer over the colder months .. maybe... if there is enough solar.

However, there is another thought that springs to mind and that is of leaving the boiler completely off for 4/5 months. Is that really good for it? Is it better that the boiler were used periodically? I would hate to save a few quid on oil only to have to have the boiler repaired due to some issue caused by it not being used for a prolonged period. 

iotum

However, there is another thought that springs to mind and that is of leaving the boiler completely off for 4/5 months. Is that really good for it? Is it better that the boiler were used periodically? I would hate to save a few quid on oil only to have to have the boiler repaired due to some issue caused by it not being used for a prolonged period. 

I've read that it's a good idea to at least turn the boiler on a few times during the summer months to prevent things from getting stuck.  I think the main risk would be the pump seizing up and sludge in radiators blocking up pipes.  But I'm no plumber so maybe someone else knows better.

EcoScruples

I don't run my boiler for the rads from April to October, always have it serviced in October before start up and never had an issue that's been down to being off.
I do run it occasionally (maybe twice a month) to heat some water but only for an hour.

Regular servicing will ensure it works when needed.

JKenH

Since getting my solar panels and iBoost in 2018 I went months without using the boiler in summer. I had it serviced in 2022 for the first time since 2008; that’s 14 years without any problems in between. Amazingly a couple of months later I had an issue with a solenoid (I think) and incurred a call out charge getting it fixed. This year I had a leak from a union on an oil feed pipe dripping onto the insulation which then made a smell when it got hot. Rather than incur a call out fee I booked a service and the boilerman fixed the leak at the same time. 

My attitude with oil boilers has been along the lines, “if it ain’t broke don’t mend it”.