Looking for reference sites and installer recommendations
Posted by: @iancalderbankthere are no other heat sources
Don't forget people are heat sources. If you had a number of house guests, you had a number of mobile radiators/convectors... Estimates vary as to how hot we are (sic) but a commonly quoted figure is we are rated at 100W so if you had ten people in the house that's the same as a 1kW heater.
I agree, empirical evidence is always better than theoretical predictions. I also agree with @kev-m, even manufacturers' engineering data can be optimistic. The way to spot whether defrost cycles have been factored in is to plot the output against ambient temp, and look for a dip in output around 5 to 0 degrees ambient. If there is one, that is probably the defrost cycle effect showing up, meaning their effects have been included. Here's a quick plot for my 14kW (ha ha very funny) Midea heat pump at 50 degree LWT. It's not perfect, because of course with weather comp you don't have a constant LWT, but you can see a dip around 5 degrees either side of zero ambient, meaning defrost effects probably have been included:
Here's another way of looking at the data, from a chart I did a while back. It's a bit harder to get your head round, as it plots output against LWT for various ambients, but the clue to defrosts is in the gap between the drab olive 5 degree line and the mid blue zero line. That gap is the effect of defrost cycles kicking in:
Midea 14kW (for now...) ASHP heating both building and DHW
Posted by: @jswhite@derek-m
I've been trying to think of a solution to this. Apparently the inner wall and outer stone is not suitable for cavity insulation. I was wondering if I could line the inner wall (and ceiling) with kingspan or equivalent straight onto the current plaster and then finish off with something a little more attractive. Half the room is already well insulated but the other half might benefit. We would lose width on a 3.3metre wide room but could probably live with that if it made a difference.
I'm not an expert when it comes to insulation, so I would suggest that you talk to a suitable company. Though more expensive, external wall insulation would probably be better, since the walls then form part of the thermal mass.
@jswhite you can buy insulated plaster with vapour barrier built in. However its best to install a vapour barrier if you want to insulate a wall like yours - it'll prevent condensation and will allow you to insulate the room on the inside.
https://www.fastbuildsupplies.co.uk/knowledge-hub/does-project-need-vapour-barrier/
Somehow I managed to screw up the x-axis in the second chart in the post above - here is the chart with the correct x-axis labels (can't edit the previous post):
Midea 14kW (for now...) ASHP heating both building and DHW
Posted by: @jswhiteI was wondering if I could line the inner wall (and ceiling) with kingspan or equivalent straight onto the current plaster and then finish off with something a little more attractive
I hate to be that person, but please do consider the vapour-openness of your walls. Sealing in the moisture with kingspan or a vapour barrier or even gypsum plaster could lead to issues down the line. There are insulating lime plasters (made more insulating with cork, glass bead or hemp), but are intrusive, time-consuming and expensive to install.
Posted by: @chickenbigPosted by: @jswhiteI was wondering if I could line the inner wall (and ceiling) with kingspan or equivalent straight onto the current plaster and then finish off with something a little more attractive
I hate to be that person, but please do consider the vapour-openness of your walls. Sealing in the moisture with kingspan or a vapour barrier or even gypsum plaster could lead to issues down the line. There are insulating lime plasters (made more insulating with cork, glass bead or hemp), but are intrusive, time-consuming and expensive to install.
If problems were to occur in the future, could MVHR help to resolve them?
Posted by: @derek-mIf problems were to occur in the future, could MVHR help to resolve them?
For the moisture inside the house? I suppose so. https://www.greenbuildingstore.co.uk/information-hub/internal-wall-insulation/ seems relevant!
I'm annoyed I didn't install MVHR when I had the chance. Retrofitting would be expensive and annoying.
- 22 Forums
- 2,087 Topics
- 46 K Posts
- 37 Online
- 3,379 Members
Join Us!
Trusted Installers
Struggling to find a reliable heat pump installer? A poor installation can lead to inefficiencies and high running costs. We now connect homeowners with top-rated installers who deliver quality work and excellent service.
✅ Verified, trusted & experienced installers
✅ Nationwide coverage expanding
✅ Special offers available
Latest Posts
-
RE: Solar to power Heat Pump for DHW
Wow, how big is your heat pump that it is pulling 6kW d...
By Old_Scientist , 29 minutes ago
-
RE: Mitsubishi Ecodan Fails to Heat Water despite temperature drop
Hep. Max drop is 10C. Tried changing and it 5C made no ...
By m1kegibson , 1 hour ago
-
RE: Air source heat pump roll call – what heat pump brand and model do you have?
@jamespa Hi, No major issues just learning to live...
By DowallyDrifter , 3 hours ago
-
RE: Commencing on an ASHP Installation Process
Quick progress update. It looks like there are only 2 ...
By Sheriff Fatman , 7 hours ago
-
There are DHW tanks with a built in heat pump that take...
By JamesPa , 17 hours ago
-
RE: Vaillant AroTherm Plus 7kW
If the thermostat is connected to the call for heat ter...
By JamesPa , 1 day ago
-
RE: Renewables & Heat Pumps in the News
Yes I realise I'm picking this up a week late...... but...
By Transparent , 2 days ago
-
@editor Mars if you have any recommendations for down s...
By abam48 , 3 days ago
-
RE: Surface mount or bury primaries for heat pump installation?
@tomasmcguinness HI, The rules is a best practise, the ...
By ASHP-BOBBA , 3 days ago
-
RE: Getting the best out of a heat pump - is Homely a possible answer?
@cathoderay how did you get a script to run for that- d...
By benson , 3 days ago
-
RE: Renewable Heating Hub Homeowners' Q&A Podcast
@ashp-bobba thank you, and equally so, thank you for ta...
By Mars , 4 days ago
-
@judith good to know… I’ll continue to feed Wattson, an...
By Mars , 5 days ago
-
RE: My misgivings about installing ASHP and solar panels via the ECO4 scheme...
@editor great article re accreditation. I note ISO/IEC ...
By Bart , 5 days ago
-
RE: Who's your electricity provider and what's your tariff?
I don't (yet), but my PW3 is due to be installed shortl...
By Old_Scientist , 6 days ago
-
RE: MCS and NAPIT complaints process
@chrislay, is your heat pump complaint still unresolved...
By Mars , 6 days ago
-
RE: ASHP Install from hell - help please
@saf1973 I’ve been going through old cases on the forum...
By Mars , 6 days ago
-
RE: RDSAP10 effect on existing heat pump EPC rating?
@aaron There's the rub, the database does not list my ...
By AF1 , 7 days ago