@johnmo Ours was insulated before we moved in in 1985 - we have ICI manufactured beads and they really did find their way everywhere. An extension had been built on and RSJ’s had been used that breached the original cavity of the original outside wall - the beads found ther way into those breach points in the brickwork and filled every gap! Regards, Toodles.

@lucia Rogue tradesmen have a lot to answer for! 😳😩 (Bring back Hanging I say!😉) Toodles.

@johnmo Thanks, doesn't seem too difficult. how deep should I bury it?. He said a meter which seems OTT !

@lucia do you know when the CWI was carried out and did it have a CIGA certificate? if you do then it’s a 25-year guarantee against poor work and they will cover remedial works up to £20k. If you don’t have a certificate it’s still worth checking with them if your insulation work was covered by them and allow you to claim.

CIGA.CO.UK "https://ciga.co.uk/guarantee-holders/"

Guarantee Holders | CIGA

Posted by: @jancold

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Thanks, doesn't seem too difficult. how deep should I bury it?. He said a meter which seems OTT

Mine is a couple spades deep, so about 600mm. 

@dougmlancs Thank you - that's definitely worth a try. I know the loft insulation was done in 2006 and the firm went bankrupt (my GBIS assessor found their business card in the loft and my EPC assessor told me the gory details). I can try and check if the same company did the walls. 

The house belonged to my parents in 2006 and they wouldn't have had a clue really, so I can't imagine they used 2 different companies. 🤞🏻

@lucia If you have larger emitters (radiators) then a lower flow temperature can be used to provide the same heat loss. As well as the COP varying with flow temperature, so does the output, here is an article

FIREPOWERHEATING.CO.UK "https://www.firepowerheating.co.uk/heat-pump-outputs-explained-pumps-help-and-advice"

Heat pump outputs vary with outside temperature and flow temperature

It

@bontwoody yes, I understand about larger rads and lower flow temperatures what I don't grasp (and that page doesn't explain because I don't see any mention of heat pump size) is how much a possibly undersized heat pump can make up the heat temps.

If my heat loss is 5.61 kw how much do I need to improve the emitters with a 4Kw heat pump to get it to supply sufficient heat to be warm? (I'm an absolute wuss about the cold 😁). 

Will exchanging my 11s for K2s make a 4kw heat pump meet or exceed that heat loss for example? Can a 4kw be coaxed to do that? I'm not considering water heating here either or defrost cycles. 

Or should I do both.... lobby for the 6kw and bigger emitters? 

@lucia in your position, given a second survey that confirms what you suspected about the heat loss and agrees with your own calculation I wouldn't accept the Octopus proposal as-is. To me its a no-brainer to push for the 6kW Daikin if that meets the predicted heat loss. If you do get the cavity insulation fixed later that will mean you immediately reduce your individual room heat losses and can turn down the flow temperature and gain more efficiency

Also with the BG quote being higher than Octopus, how far off the estimate Heat Geek's site gives is it? Just curious as to the spread between the big energy suppliers and Heat Geek.

@gunboatdiplomat I haven't done a Heat Geek calc but have done a de Podesta calc on 1year's metered gas use (which HG reckon is ok). This gave me 5.61kw which interestingly, the BG MCS survey that was run as 'no wall insulation' almost matched.

This then computes as a 6kw heat pump and all the rads upgraded. and made the cost about £1,700 higher than Octopus (plus paying for gas capping and removal and much higher annual maintenance fees). 

@lucia don’t whatever you do go with a 4kW Daikin, our annual gas bill of 18000kWh means we need a 6.7kW ashp your 16000 means you need a 5.5kW (ish) The Daikin will be about 3.7KW you’ll be cold and it will try to go hotter and you’ll be skint too.

@lucia you can’t improve the emitters  to get more wattage out of a heat pump. All you can do is put an electric fire on!

or wear more clothes and live in a cooler house eg 15-18C. Not my idea of comfort.