Help with air source heat pump

[joth]

52 minutes ago, sharpener said:

Some of the claims in that link are pretty doubtful though.

• Afinia aluminium radiators are more efficient than traditional radiator materials, such as steel and cast iron
• Incredibly effective thermal conductors and with low energy consumption, Afinia radiators can help lower energy bills
• The range can deliver exceptional room comfort, heating up and cooling down very quickly which allows Afinia radiators to respond quickly to any changes in the temperature demand set by the thermostat

Except for heat lost from the back via an external wall (which will not vary a great deal) all radiators are 100% efficient in terms of the heat getting from the pipework into the room.

 

The radiators themselves do not and cannot have any intrinsic "energy consumption", low or otherwise. (Even with fan-assisted radiators the motor power ends up in the room.)

 

Claims about warm-up time are I think illusory, the thermal mass of the metalwork is small compared with the water content and very small compared with the room itself.

 

All the usual misleading advertising guff IMO.

A lot of people mix up efficiency and speed, especially when it comes to heating. It's like saying a Ferrari must be more efficient as it gets you there sooner. 

 

Being very generous, you could read it as time efficient. Like, an electric fan heater is very time efficient way to warm up a room; you waste less time waiting for it. But a heatpump will cost less doing it 

 

Notwithstanding that, totally agree different metals is complete BS.

The one caveat is a badly furred up rad would be less time and money efficient: it is effectively internally insulated so the full heat never really gets out of it so over extended period you waste a lot more heat on the circulation pipework (especially if it goes through cold zones) vs the small amount actually usefully delivered to the room 

Edited November 24, 2023 by joth

[thenight]

1 hour ago, ReedRichards said:

I have two Grant aluminium radiators that look very nice to me; I would consider then "Designer".  But their heat output is good.

 

https://www.grantuk.com/products/aluminium-radiators/afinia-radiators/   

 

My upstairs radiators have a similar look to these. Great choice 🙂

[crispy_wafer]

12 minutes ago, thenight said:

How do you heat your property.. electric?

 

Currently like a cave dweller 🤣!  Stove with backboiler. 

 

Will be a heatpump in the self build, supplemented by air 2 air and a dinky stove, just waiting for electrics to be sorted then I'll plumb it in.  The overriding thought on ASHP's certainly round this forum is positive, just do your due diligence, bring the property up to spec if needed insulation wise, look at air tightness and sources of unwanted ventilation then you'll stand a fighting chance of having something that will run at lower temperatures and give you efficiencies that match up with the cost of gas.  Be mindful though that it may not save you money!

[thenight]

6 minutes ago, crispy_wafer said:

Currently like a cave dweller 🤣!

 

😂😂😂

 

7 minutes ago, crispy_wafer said:

Be mindful though that it may not save you money!

I've read this in some of the heat pump horror stories

[sharpener]

Not really a horror story. Mostly it's because elecricity is approx 3x as expensive as gas, but the CoP of an HP is also in the region of 3x so the cost relative to a gas boiler is down to small differences in the two and may be more or less.

 

Hence the emphasis on running the HP from off-peak electricity as far as practicable. The amount of energy needed is beyond the scope of small domestic battery systems.

 

The situation in Norway is rather different, they have a history of cheap hydroelectric power (dating from before their exploitation of oil and gas fields) so saving 2/3 of consumption by upgrading from resistive heating to heat pumps is a no-brainer. There is also much more use of MVHR which helps.

[thenight]

Thanks for all of your help!

[Ferdinand]

Let me add a couple of comments.

 

1 - We have our own Heat Model spreadsheet written by a former member, which many have found useful. Here:

 

2 - I often think that the easy way to upgrade your radiator is to upgrade from single to double panels as often as needed. Less new plumbing required.

 

OTOH redoing radiators and pipework can be quite cheap - the last house (I am an LL) I did replacing all the radiators and pipework was only slightly more than a Powerflush. 

 

3 - I think your £499 British Gas number indicates £7999 minus the grant which goes direct to the supplier.

 

4 - When you get your EPC done, ,make sure you can prove all your good insulation points, and discuss beforehand with your EPC consultant.

If it is not proven (eg 2G performance, possibly cavity insulation) they quite often have to make low-value assumptions, which can slug your number. 

F

[thenight]

On 26/11/2023 at 11:22, Ferdinand said:

3 - I think your £499 British Gas number indicates £7999 minus the grant which goes direct to the supplier.

I've done quite a bit of research this weekend and £7999 doesn't sound bad. I expect that is providing all radiators are good enough and there is no extra insulation required.

Thanks for your help Ferdinand

[Ferdinand]

1 hour ago, thenight said:

I've done quite a bit of research this weekend and £7999 doesn't sound bad. I expect that is providing all radiators are good enough and there is no extra insulation required.

Thanks for your help Ferdinand

 

To me the Octopus deals look potentially good, as they cover necessary radiator work, and other things too.

 

https://octopus.energy/get-a-heat-pump/