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British Gas versus Octopus: Two possible heat pump routes - how to evaluate them?

 
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Air Source Heat Pumps (ASHPs)
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 Johnmo
(@johnmo)
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12/07/2024 1:31 pm  

Posted by: @lucia
↑

Reality - half insulated cavity wall

Half insulation is as bad as no insulation. Bit like a hole in a bucket. It may be a bucket but it's not holding the water.

Maxa i32V5 6kW ASHP (heat and cooling)
6.5kW PV
13.5kW GivEnergy AIO Battery.


   
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 Johnmo
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12/07/2024 1:34 pm  

Posted by: @lucia
↑

Question:What would you do? 

BG and get all the rads changed out for bigger. Allows you run cooler for better running costs. If it's too big you can sort out the cycling. Mine is a 6kW on a 3kW max duty and not much modulation. Works fine.

Maxa i32V5 6kW ASHP (heat and cooling)
6.5kW PV
13.5kW GivEnergy AIO Battery.


   
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 Lucia
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Topic starter 12/07/2024 2:10 pm  

@johnmo You have a 6kw Daikin? 

Good point about the bucket... 

My preference if going for the 6kw is to try and convince Octopus to accept it. I prefer their whole approach. Plus BG want a lot more money for the 6kw set up. 

This problem is caused by MCS regs and EPC ridiculousness. Neither account for problems with the insulation - it's either insulated or not. The EPC says insulated - the borescope (which was done for a different purpose says it's not insulated everywhere....) - 🤦🏻‍♀️


   
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Toodles
 Toodles
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12/07/2024 2:23 pm  

@johnmo That might depend how high up the hole is in the bucket! 😉 Toodles

Toodles, he heats his home with cold draughts and cooks his food with magnets.


   
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Jancold
 Jancold
(@jancold)
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12/07/2024 2:25 pm  

BG have been and quoted at about 1/3 off the original website estimate.

They would change 3 Emitters (as they are now called!) and add one on the landing and came up with 4Kw heat loss which agrees with Ultimate Renewables. My foray into Heatpunk gave 4.9Kw . It would be a Daikin HP.

He appeared to accept my 'no buffer' request but slipped it into the quote!

I would also have to prepare the site for the ASHP with buried pipework for my preferred position which is the other side of a path around the house, about 1 meter away from the house. Where can I find information on a suitable pipe system and fittings?

This was only the quote survey so I look forward to getting the detail later.

Daikin 6Kw ASHP.
MG4 EV
1926 Semi with loft and wall cavity insulation, all radiator.


   
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Toodles
 Toodles
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12/07/2024 2:29 pm  

@jancold Mars may be able to help you with the insulated pipe runs I think. Toodles.

Toodles, he heats his home with cold draughts and cooks his food with magnets.


   
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 Johnmo
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12/07/2024 2:31 pm  

Posted by: @toodles
↑

@johnmo That might depend how high up the hole is in the bucket! 😉 Toodles

I know what your saying but - Not really, heat will take the path of least resistance, that's why it's so important to get no gaps in insulation. If the cavity is incomplete don't take any credit for it, that is the correct thing to do.

 

Maxa i32V5 6kW ASHP (heat and cooling)
6.5kW PV
13.5kW GivEnergy AIO Battery.


   
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 Johnmo
(@johnmo)
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12/07/2024 2:39 pm  

Posted by: @jancold
↑

Where can I find information on a suitable pipe system and fittings?

I made my own.

110mm flexible underground conduit I had black left over from the build. Inside 28mm Hep2O pipe, and closed cell (armour flex 25mm wall thickness insulation. Wrapped the insulation in aluminium tape. Where the conduit and pipe came out the ground used stainless steel mesh on the end of the assembly to keep wildlife out, foamed into place. Once out of the ground used UV resistant insulation and a 90 Deg fitting to take through the wall.

Maxa i32V5 6kW ASHP (heat and cooling)
6.5kW PV
13.5kW GivEnergy AIO Battery.


   
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Toodles
 Toodles
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12/07/2024 2:40 pm  

@johnmo Can such partial insulation jobs be ‘topped up’ or is there a practical method of removal so that a ‘proper job’ could be carried out subsequently? Regards, Toodles.

Toodles, he heats his home with cold draughts and cooks his food with magnets.


   
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 Johnmo
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12/07/2024 2:46 pm  

Posted by: @toodles
↑

Can such partial insulation jobs be ‘topped up’ or is there a practical method of removal so that a ‘proper job’ could be carried out subsequently

You can normally get mineral wool blown in or use EPS beads they should make their way to fill everything up fully. Beads are less likely to settle later and don't hang on to water if you did get days (or weeks) of rain like we just have.

Maxa i32V5 6kW ASHP (heat and cooling)
6.5kW PV
13.5kW GivEnergy AIO Battery.


   
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 Lucia
(@lucia)
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Topic starter 12/07/2024 2:56 pm  

@toodles No, it can't be topped up.


   
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 Lucia
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Topic starter 12/07/2024 2:58 pm  

@johnmo You have to extract everything first and only then can you refill it. Even for a small bungalow like mine it's £3,000 at least. I can't afford to do that.


   
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