Switching from oil to a heat pump

[Avocet]

Are BOTH numbers just Guesstimates?
i.e. best guesses based on the limited info they both have on your home's heating and water needs - possibly from somewhere such as the last EPC, perhaps? Such that BOTH are subject to a (paid for) survey and room by room heat loss/gain calculations to refine what is actually needed (and the cost no doubt)?

Do both include the cost of removal and licensed disposal of oil boiler, tank, pipework including any kerosene left in the tank?

The 150 litre water cylinder is a tad small for a family home, and the 300 litre a tad large... So the two 'quotes' seem not to be "like for like" assumptions at all.

Octopus only seem to offer their own Cosy Heat Pumps up to 11.3kW heat loss and the Grant 15.5kW for larger, lossier homes... Not sure I'd be keen on their own brand (must do more reading on them in those other forums).

The Heatgeeks one will be a guesstimate. I just went on their website, stuck in my address and a couple of details and left its algorithm to "do its thing". The Octopus one was after a bloke came and spent about three hours here, measuring windows and the like.

The Heatgeeks one came with an estimated 12.66kW heat loss (don't know how, but we do have a pretty recent EPC. They estimated the floor area at 208m^2 the Octopus one reckoned 193m^2 (I know, because I have accurate drawings from when we extended the house in 2008 that it's actually 219m^2, but the Octopus guy said he'd knock the porch off as we don't heat that). Either way, they're in the same ball park. Octopus reckoned the heat loss was 10.578 kW

Slightly puzzling that Heatgeeks are recommending a smaller pump for a higher heat loss and floor area though? The Octopus quote assumes a design outdoor temperature of -3.7 decrees C. Heatgeeks guarantees an efficiency of 340%. With Octopus it's 360%, but in the smallprint it says that's an annual average, whereas the Heatgeeks quote doesn't say what it's based on, but I'm assuming that 340% at even zero degrees outside, is "optimistic"?

Apologies, the Heatgeeks quote was for a 210L cylinder not 150.

NEITHER includes anything to do with getting rid of the existing oil tank or its contents - although the latter won't be a problem round here, as lots of people are still on oil and I reckon I can sell that at £20 for a 25l drum! Plenty of farmers always looking for oil oil tanks too.

 

[drives]

The heatgeek efficiency guarantee will be the SCOP (annual) as well.

Only one way the heatgeek quote will be going presumably once they do a survey, and they may well be sizing up the unit afterwards.

That octopus quote will be very difficult to beat I think. The proposed unit sizing looks reasonable, taking into account the calculated heat loss (which again on the face of it sounds about right for the size of your house and if average insulation levels for year), and giving a bit of a buffer for DHW demand and defrost cycles.