Octopus exclude them from other installations, they wanted to exclude it from mine.
Now, I suspect because it suits them, it must be heated.
Does anybody now the MCS rules?
Does anybody feel I have been hard done by, the original heat loss survey was materially incorrect and decisions were made based on that, are Octopus being reasonable now in saying what they are?
Surely any competent person would have excluded this problem area from the heat loss calculation, fitted a suitably sized heat pump for the house and found an alternative solution for the problem areas such as the under floor heating already fitted and operational or oil filled radiators or fan heaters.
Any of those would have resulted in better efficiency and lower running costs than fitting a heat pump that is clearly to big for the property.
I don’t know how any of that fits with MCS rules but the MCS don’t live here, they don’t have to deal with the problem and they don’t have to pay for it.
This cannot be how the MCS want this to work, they must have considered exceptional circumstances where one difficult to heat area has a significant influence over the rest of the property?
It looks like your input processing in emoncms.org is linked to the data coming from the meter on your backup heater and so when you turned it off those inputs stopped updating. Do you want me to fix it for you?
I can also fix what would otherwise be a small gap in your data if you want? e.g between the time you switched off the meter and the point we reconfigure the inputs…
The booster and back up heaters show up separately in my feeds and they are reporting correctly.
The booster is on electricity 2 and the back up is on electricity 3
The heat pump itself is on the first electricity feed and the circulation pump is being reported and that has always been reported on the first electricity feed along with the normal consumption.
I thought they were three completely separate feeds, how can the booster and back up affect the others, I never see any back up heater use normally.
If you can fix though that would be great thank you
Wow that’s incredible isn’t it! To think how many other systems out there have this backup heater coming on Look at the COP jump up now (All fixed for you)
The inputs for these had stopped, I assume because turning off the circuits turned off the SDM120 meters themselves.
Do you think 5100W heat loss for the house at -3C is accurate? Do you expect to put in 122 kWh of heat on -3C days? Or is this assuming overly high air change rates and actual heat loss is lower? You put in 83 kWh yesterday, will be interesting to see what you need to put in per day over this cold snap…
It will hopefully give the data we need to have more confidence on this.
The most gas I ever used was 110kWh in a day last December
I didn’t use 83kWh of heat yesterday, 8kWh of that was hot water so it was I think 74kWh of heat into the house (including conservatory) yesterday.
My average internal temperature yesterday was 23.5c, as we know I am running it warmer than design.
So I had a heat loss yesterday when it was an average 6.3c outside and 23.5c indoors of 3.08kW
So heat loss is 3.08kW at a temperature difference of 17.2c
At my heat loss calculation the average room temperature would be 20c at -2.3c outside
What do we think the heat loss will be at a difference of 22.3c if it was 3.08kW at 17.2c
Remember this includes the house and the conservatory.
Depending on your views, whether if as @ColinS suggests you start at 16c or I just do it linearly I make the heat loss somewhere between 4kW and 5kW, that is for the house and conservatory.
The house heat loss is not 5.1kW and the conservatory is not 2.3kW, the whole lot is 5kW or less.
The data supports that as far as I am concerned.
Have I got something wrong?
My heat loss is not 7.4kW and my house certainly does not lose 5.1kW, it’s impossible based on my heating history and the data gathered here since I have been using the heat pump.
The surveyor showed me the screen on his heat loss calculation, he was unable to edit the air change rates for each room, he said they were set by the MCS based on the age of the house, in my case 1960 to 1999 is the band I fell into. There were different air changes based on the type of room.
That approach is valid and it’s difficult not to endorse it*
However…in this case using eyeballs and tape measures would result in a lower cost installation through downsized equipment which also happened to operate with higher efficiency.
I wouldn’t want to conflate making an educated commercial decision with excusing poor performance on the grounds that doing better automatically costs money though.
*Today’s job here is getting the ground loop filled and trying to get the heat pump proper running whilst the car can still get vaguely near.
In the interim a little (9k BTU; €600) AC is in. Set to “30” overnight as an experiment (ambient is averaging around 0C over 24 hrs) the poor little thing spends 20 mins of every hour defrosting. It gets the place to 25C though and would probably keep doing 20C internal down to say -10C.
Why the heck am I fitting this ground source unit I ask myself sometimes. Partly was £600 on eBay and that’s not far off what an invented cylinder costs. Partly comfort of rads vs air movement (though it has to be said that in a well insulated place you need so little heat that a 9000 BTU class unit isn’t like sitting between a hairdryer and the fridge like it is in typical British houses). Mostly lack of experience and trust with the a2a units until now.
Where an I going with this?
Model an idiot proof sCOP 5 air to air unit to supplement a gas combi for heating most of the time; leaving the gas combi for DHW; and you do have to ask why we’re subsidising wet heating at all…
I think where data is available this should be the way the heatpump should be sized, with a signature from the customer to say they are happy with the comfort levels this heat input entails…
In your case it would indicate ~4kW if the boiler was 85% efficient . Your 3 kw / 17k calc comes out about the same.
In theory, the big suppliers like Octopus and British Gas can’t do that due to competition law but they can try until stopped by an annoying court case.
Anyway the 9kW Daikin would be fine it it behaved how you might expect.
This is the problem I keep coming back to, I knew it was too big in terms of it’s maximum output, I would never need it but I thought it would have a wider range of operation.
When I look at the older 7kW Daikin, it is happy to put out 1,500w using 300w of electricity.
I thought that this 9kW is just a bit bigger, the next one up, it won’t go quite as low but it will be fine.
But that isn’t what they have done, they jumped from a 7kW to a 16kW, my 9kW goes no lower than the 16kW, they produced a 16kW heat pump and turned it down at the upper end in three stages to create the range, if you need a 16kW great, if you need 9kW than it is always going to be more difficult, even more difficult when it is oversized for the property and when it is grossly oversized it’s a disaster.
The are not going up in small steps as you would think, it’s a massive leap going from the 7 to the 9.
As my house only needed a 7kW or less then it’s a huge problem.
I am at work this morning and I have just remembered another couple of gems from my conversation with Octopus yesterday.
They said that I should never try to run on just pure weather compensation, the system is only designed to run with Madoka control of the room temperature.
One of the final comments when we talking about my previous gas usage and my heat production so far was that although a smaller heat pump might suit my needs they were bound to consider the needs of future owners of our house for whom a bigger heat pump would be more appropriate.
So I have to have this just in case somebody else wants it even though I don’t and I paid for it.
Thinking about my heat production, it’s looking clear that I will rarely, if ever, need more than the minimum heat output of this heat pump. I don’t think there could be a bigger clue that it is oversized.
You should stop conversing through deniable channels if you want to get anywhere.
Whilst what they’re saying is totally in character it’s also totally deniable unfortunately. Unless they’re prepared to share the call recordings.
Ask if they’re recorded then subject access request them for posterity perhaps?
On the “suitable for others” line; ask what the operative design temperatures are explicitly then ask if those would be suitable for 90 year olds to shut down that weasel avenue…
that will do wonders for your COP!
