So how much is an Energy Expert visit? Got an email saying pay £100 but it's advertised as £25?

Exactly like that. 

Also this was the email (edited to remove numbers)

I was posting in case others had the same experience of being advised full price, then only charged the discount.

Ah well. 13:23. Phone call from OVO to advise that the assessor won't be coming today as he's let them know he has trouble with his vehicle.

New appointment booked for next week, free as an apology. I should be getting a call before to advise they're on their way.

New system lots of learning opportunities 😉

Visit today. Much more thorough than before, and than an EPC we got recently as executors.

The confirmation email gave the assessor’s name, which the original one didn’t have. It said we’d get a phone call beforehand.

Yesterday afternoon, I got a phone call from the assessor confirming the time, as promised.

Today he turned up in his OVO electric car, and did a far more thorough job than the 2015 one I had for solar panels. The rating has dropped from 83 to 81, primarily due to the correct build year being used in the assessment. It seems there was a slight regulations change in insulation thickness just after our house was built.

There is currently nowhere to record the house batteries, though an update is coming in a spring 2024 to the RdSAP system.

He took many photos outside and in including the loft (which get used to quality assure his work), and reviewed the installation certificates for the cavity wall insulation, boiler etc. He checked temperatures on boiler and hot water tank and TRVs. He checked the smart meters.

We discussed aspects of the house and insulation as we went round the house, which was useful. We could perhaps make marginal savings in running costs but at huge expense - the likes of triple glazing instead of double.

Wonderfully, he was able to lodge the EPC before he left, so we could discuss it before he left.  Its immediately available on the government website.

Our house is still assessed B, now 81 could be 85 (was 83 could be 87).

At the end of the day, there are only two recommendations, which haven’t changed.

1. Floor insulation (Suspended floor) based on the build date of the house.  Rather than what the first EPC provider suggested of that being between ground and first, this refers to the ground floor.   However, today’s assessor expects from his previous experience with the NHBC and the lack of any movement in the floor that it will be concrete beams, and perhaps not capable of being effectively insulated.  The system quotes £800-£1200 to save £204pa. Ridiculously that cost is IDENTICAL to the cost in 2015 (apparently updates are due next year). Bearing in mind that as executor recently, it cost £378 to lift two floor boards, assess a springy floor, and then merely replace the packing between a couple of joists and 3 brick pillars beneath, in ONE ROOM, that cost for a 4 bed detached house is unlikely.
2. Solar water heating £4000-£6000 (again identical to 2015) to save £87 pa, a payback period in excess of 45 years. That makes no sense. I last got an estimate for solar water heating in 2019 at £6500. 

As he is employed by OVO, there were opportunities available for further consideration and perhaps a visit from a different person.  But we’ve got most of the things on the list, eg solar, tado, a boiler servicing arrangement, don’t have an EV (charging point on offer), and can’t fit an air source heat pump in its current design.

The two suggestions in the EPC aren’t covered by offerings from OVO.  I’ll have to see if any builder shows any interest in looking at insulating the floor, but even if possible I expect a FAR higher cost estimate.

Overall worth it for £25. If you need an EPC even the £100 isn’t much more than the quick and dirty version offered through estate agents which seem to contain several assumptions. That’s from my experience looking up nearby ones for ours and the house we sold as executors. I just wish the whole EPC system was more realistic.

BUT @Abby_OVO no price emails have come since your interventions. Perhaps as the first mix-up offered me a free visit, they didn’t see any need for one. I can’t say I’m worried.