April 2022 5k towards heat pump

[Paul_F]

image_2021-11-14_083033.png (83.38 KiB) Viewed 3665 times

[Ken]

Here is just one extract from the Energy Saving Trust ref above. Remember that these systems were professional installed and overseen by HP manufacturers and yet the following alterations had to be made after installation.

Examples of heat pump interventions Table 3
Major (12 sites) Medium (9 sites) Minor (11 sites)
Replacement with new heat pump Re-filling ground loop Changing control pattern
Reduce the area heated by heat pump Installation of new hot water tank Adding extra insulation
Repair a leak to the ground loop Connection of shower to heat pump system Disabling auxiliary heater
Recharging refrigerant Installing new radiators Adding insulation to pipes
Installing new circulation pump

There is no way that HPs can displace gas boilers purely on cost especially at the moment with a price differential gas to leccy of 5ish and even at 3 it must be debatable.

What people are forgetting is that to achieve the high efficiency COP they have to spend a lot of money on top of the HP either to reduce the heat demand or to have rooms full of rad or to have low COPS and high bills. Take your choice.

The work by Trystan Lea is truly excellent and we should truly thank him for this. He shows what a properly designed system can do in the right circumstances but this is totally inapplicable to most houses ON A COST BASIS

[spread-tee]

Hear hear Ken, 5 grand on heatpumps is nuts, they're barking up the wrong tree.

Desp

[Moxi]

We should send forum invites to the relevant ministers and their shadow counterparts- they may learn a few things ! I know I learn something every day I read the posts.

Moxi

[spread-tee]

Why not?, also a list of recommendations to reduce a domestic carbon footprint in a cost effective way?

Desp

[Andy]

Andy

Would be interested in a chat as I am looking at a GSHP system as I can’t convince myself the an ASHP will cut it up here (Aberdeenshire) inspite of what a couple of companies say. For exactly the reasons you site.

Why don't you start a new thread and we can all contribute . I do have a friend who built a house recently and he has an ashp. He had considerably lower bills than us despite having a much larger floor space. Modern spec insulation and UFH + upside down house go a long way towards making it work. He also runs the house cooler than I am allowed to

[marshman]

_

[Paul_F]

Amazing COP figures for that ASHP. BUT looking at the total consumption over 12 months at 1945kWh (space heating + DHW) for a mid terrace house did make me raise an eyebrow or two! My GSHP which I guestimate averages out at a similar level - i.e. 3.5 to 4, last year used 1345kWh in a 5 bed detached house of some 240sqm. OK I thought he is in N. Wales. maybe it was a lot colder, but looking at the mean temperatures outside they are remarkably similar to what I recorded for the same period, and also my internal temperatures are higher with an average closer to 20 deg C. We are in a windy exposed position as well. Now either it shows how much difference decent insulation levels, draught proofing and controlled ventilation, triple glazing etc. makes or his heat meter is over reading. I haven't read all of his blog and he does seem to be quite thorough but I wonder if he has verified the heat meter readings - easy to do by monitoring a heating cycle for the DHW where you know the start and end temps and the volume of water heated.

Walls are solid stone, and heat demand is within 20% or so (under) the SAP calculation. He's also accounted for most of the deltas between his readings and the SAP calculation. That's the impact of insulation, but then again given that the total demand is relatively small it's not obvious that better insulation is still a high priority.