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Replacing Worcester oil boiler with an ASHP

JulianC · 2021-03-30T18:15:26Z

I am replacing my 25/32 Worcester oil boiler with an ASHP Had discussions with many suppliers, a lot of whom wouldn't quote because we have 10mm pipe drops to each radiator, from 28mm loft pipes. Anyway: 201m2 bungalow. Built 2001. EPC rating of B after triple glazing, 300mm of loft insulation. We currently use between 1220-1500L of oil per annum. 100A incoming circuit. ASHP approved by DNO (Western Power). 20,500kWh of heating energy required. 3000kWh of hot water demand from the EPC. An energy loss calc and room by room heat demand has been undertaken. This has lead me to select Ecobubl from Winchester to undertake the work. They have proposed a Daikin Altherma 3H HT 18kW ASHP. Also a Mixergy 150L H/W tank - but we are also considering a standard cylinder with a large internal coil, to maximise the ASHP. And a 3kW immersion to use my 4kW of PV and Solic 200 electric diverter. Simple control system, using my current Nest. Had wondered about the Homely Energy control system, but I wonder if this adds complexity. Price is £13,700 for ASHP + Mixergy + buffer tank + installation and support for RHI. I should get back about £10k through RHI. I will take photos before, during and after installation which should be 12 April

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Air Source Heat Pumps (ASHPs)

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JulianC

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Topic starter 09/12/2021 4:09 pm

Reporting performance details again.
MCS installer predicted electric demand of 2130kWh to date from installation in April.
Actual consumption is 1442kWh.
So that’s a good start.
Perhaps I need to put more effort into measuring efficiency. But my quality measurement is Mrs Jules saying the home seems warm 👍

As stated earlier, I intend to run the system for a year using the Nest wall thermostat and then switch over to the Daikin controlled heat curve and compare.

Daikin Altherma 3H HT 12kWh ASHP with Mixergy h/w cylinder; 4kW solar PV with Solic 200 electric diverter; Honda e and Volvo EX30 Ultra Twin Performance electric vehicles with Myenergi Zappi mk1 & Ohme chargers

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Kev M

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09/12/2021 4:26 pm

@julianc

Hi Julian,

what sort of daily kWh numbers have you been using lately?

Kev

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JulianC

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Topic starter 09/12/2021 6:04 pm

35kWh yesterday. Average 30kWh per day in Dec

Average 19kWh/day in November.
And average 5.5kWh/day in October

Predicted was 13.8kWh in Oct, 31.6kWh in Nov and 50kWh/day in December. 54kWh/ day for January before it drops way

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JulianC

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Topic starter 19/12/2021 6:27 pm

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JulianC

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Topic starter 19/12/2021 6:30 pm

Warmer December so far means we are using less electric to heat home than predicted against MSC ASHP model. Namely 1638.11kWh consumed versus 2532kWh predicted. Good 👍

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Derek M

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19/12/2021 7:04 pm

Posted by: @julianc

Warmer December so far means we are using less electric to heat home than predicted against MSC ASHP model. Namely 1638.11kWh consumed versus 2532kWh predicted. Good 👍

You don't believe anything MCS says do you? 🙄

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JulianC

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Topic starter 19/12/2021 7:17 pm

@derek-m haha Derek of course 😂

But it is a good way for me to track actual costs

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JulianC

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Topic starter 21/12/2021 5:11 pm

Took out the gold level Daikin ASHP support contract today. £264/year for 10 years. Fixed price. Including annual service, free parts, labour and call outs. Added cost, over and above the ASHP installation. But I think piece of mind. One of the reasons I chose Daikin over other vendors.
How much do other owners pay for an annual service?

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alastair

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02/01/2022 12:08 pm

Hi @julianc

Happy New Year

It sounds like we are getting a similar set up to you - solar panels, Mixergy tank, Daikin heat pump and battery. In a previous house we had solar panels and a Mixergy tank and loved that set up. The battery seems to be a set and forget type of system, or at least easy to tweak through an app etc. The only component that I've no experience of is the Monobloc heat pump. I've done lots of homework, and am looking forward to having it, but I was wondering what your thoughts are on the actuality of living with your heat pump and the system overall. Does it just sit there and get on with it? Or do you need to tweak it a lot? I noticed that you needed to be sure that noise wasn't an issue - is that working out OK too?

Any pointers/thoughts would be great

Cheers

Alastair

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JulianC

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Topic starter 02/01/2022 9:25 pm

@alastair Happy New Year. Similar systems (except your battery).
My Daikin ASHP is fit and forget really. We are doing a year using a Nest as the controller. I’ve set the heat to come on in the morning and gradually increase late in the day to 20.5C. Then off at night. Mixergy heats during my cheap Octopus night tariff. So I’m using the Daikin like the oil boiler it replaced. No tweaking.
So we’ve used much less electric than MCS predicted (but milder?). 1900kWh used vs 3100kWh predicted. And my wife says our home is warm. So result.
Once the trial year is up, I intend to switch to using the Daikin heat compensation curve. And do another comparison.

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alastair

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03/01/2022 10:59 am

@julianc Thanks for that response. Great to know how you are using it and that you are using less energy than predicted too. 🙂

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JulianC

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Topic starter 15/01/2022 3:15 pm

Was outside as my Daikin went into reverse/defrost cycle. Here is a photo of the start. And the steam/water vapour being cleared as the process nearer the end. Took 9 minutes. At 1 or 2 C. Home stayed warm. But COP must be impacted. I’d not really seen before.

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