Stiebel WPL 25 heat pump in South Wales with no insulation
Stiebel WPL 25
South Wales
5 Bed Detached 1900s build with cavity Wales, no insulation
Underfloor heating downstairs, rads upstairs
EV, Solar, Batteries
That's an early date to find cavity walls in Wales @shaeney
The practice became widespread after the Great War.
What material is each leaf constructed from?
What feature(s) of the Stiebel WPL 25 made you opt for it?
Or was it the installer's preference?
Save energy... recycle electrons!
Ah, perhaps all that blubber helps to insulate …. (In the ‘cavity Wales’) Sorry, couldn’t resist! 😊 Regards, Toodles.
Toodles, he heats his home with cold draughts and cooks his food with magnets.
@transparent so its weird construction.
Double engineering brick outer wall and single skin inner wall. Our buyers inspection engineer said the walls were bombproof!
Makes for very deep window recesses.
Went for Steibel because the high efficiency and high output.
That's a really sturdy outer leaf!
It's unusual to find such an over-engineered approach... especially as it's the inner-leaf which supports the roof.
As for the Steibel - are you actually achieving the level of efficiency you were after?
Have you got a controller which tells you the COP?
Save energy... recycle electrons!
@shaeney welcome to the forums. So I simply must ask given the amount of articles that persist saying that heat pumps don't heat old buildings, especially with no/little insulation. Are you warm and what are your running costs like? Did the Stiebel replace an oil boiler?
Pre-order: The Ultimate Guide to Heat Pumps
Subscribe and follow our Homeowners’ Q&A heat pump podcast
@editor Steibel replaced an old gas boiler.
When we bought house, boiler needed replacing. We wanted all the radiators gone off kitchen walls, so wanted under floor heating......
So we ripped up downstairs floors, put under floor in and went with a Heat Pump. just 2 rad changes needed upstairs, rest were already oversized.
Downstairs is mainly open plan but we do have a log burner mainly for really cold winter nights, but its for the look and feel more than heat. heating keeps up even at -6 the other night.
Running costs is about half what gas was, I estimate, but thats mainly down to the cheap overnight tariff. So I heat the underfloor mass etc with cheap energy.
I think people say you need COP of 3 to "break even" at 7p gas and 30p leccy, so I am above COP 3, then factor in average I pay for leccy is around 16p (I think), it makes a huge saving.
@shaeney super interesting. In the absence of insulation, I’m very curious to hear what the heat loss survey was. Can you walk us through that? Also what was the target temperature? 21C?
Pre-order: The Ultimate Guide to Heat Pumps
Subscribe and follow our Homeowners’ Q&A heat pump podcast
@editor the main living room is approx 30m2 with a design temp of 21 degrees at 74w/m2 for a total of 2,264. No idea how that compares to anyone else!
Theres a LOT of glass in that room with 1 set of French Doors and a triple bifold. Ceiling height is around 8 and a half foot
Total area of living space is 185m2
Posted by: @shaeneyI heat the underfloor mass etc with cheap energy.
For clarification @shaeney
so that UFH pipe is all running through a new solid/concrete floor, correct?
Concrete thickness?
Insulation below it?
I suspect that approach allows your heat-pump to operate more efficiently.
The high thermal mass, slowly heating over many hours will diminish/eradicate the HP from cycling.
Here's part of my house with the UFH pipe stapled to insulation prior to the concrete pour.
@editor -- it would be great if this could in some way be reflected in one of the heat calculators you're contemplating for this site.
But I'm unsure how to achieve that.
It needs input from one our tame HP physicists/engineers 🙂
It would be a useful feature for members here to evaluate the different efficiencies which be obtained depending on how they implemented the heat-emitting elements for their home:
- radiators
- UFH (suspended floor)
- UFH solid floor with high thermal mass
Maybe this would be better illustrated with a theoretical house, rather than the householder putting in their own details.
Save energy... recycle electrons!
@transparent so the old flooring came out, down about 8 inches, I think.
Then 4 inches of insulation went down, foil side up. The underfloor heating coils were secured to the foil side, then a few inches of "biscuit mix" screed went down over the top
Probably a total of 70m2 underfloor heating went in. Abut half is covered with quick step laminate, the other half with tiles
Great. That's what I'd imagined @shaeney
Got any photos during the works?
Was this all DIY, or did you buy in contractors?
I have tiles in the kitchen area, and engineered oak boards over the rest.
But it was more complex because that oak boarding spanned across to an area with suspended floor, running across joists. 😲
Did you fix your laminate to the screed to increase the heat-transfer?
Or does it 'float'?
I consulted Bostik technical support, who recommended a primer and an adhesive "Laybond Wood MS Polymer".
That's proved very successful, despite my fears of differential expansion rates.
Bostik really know their stuff!
Details are useful here on the forum.
Others will come across this topic in months/years to come and be able to copy the best practices from what we've achieved.
Save energy... recycle electrons!
- 26 Forums
- 2,153 Topics
- 47.3 K Posts
- 47 Online
- 5,673 Members
Join Us!
Podcast Picks
Latest Posts
-
Engineer has been. Prob air locks....undid a few things...
By Profzarkov , 53 minutes ago
-
RE: Boiling Mad: Exposing Radiatorgate
Hi @Rob, I’d be more than happy to contribute. I have ...
By DREI , 2 hours ago
-
RE: Solar Power Output – Let’s Compare Generation Figures
@andris a great year - very happy with our system
By Profzarkov , 4 hours ago
-
RE: Mitsubishi Ecodan 11kw Defrosting Issue.
A bit of a follow up on the progress of the Ecodan pump...
By ThunderMink , 4 hours ago
-
RE: A Customer's Lessons Learnt from a Heat Pump Installation in a Large House
After our rather lengthy meander off piste, I thought I...
By GrahamF , 6 hours ago
-
RE: Midea ASHP – how to set weather compensation
@pash44pump - to collect the IAT/OAT data, can I sugges...
By cathodeRay , 7 hours ago
-
RE: Ecodan software update. Real or scam?
@vinz86 Contact Mitsubishi and an engineer attends and ...
By ASHP-BOBBA , 17 hours ago
-
My Samsung Gen6 (probably same controller as yours) onl...
By Old_Scientist , 1 day ago
-
@drei When I was in local government we were of cours...
By JamesPa , 1 day ago
-
RE: Heat Pump SCOPs – The Truth Might Not Be What You Think
Sufficient system volume is also essential for ensuring...
By Old_Scientist , 1 day ago
-
RE: Flexi-Orb Heat Pump Scheme: A Game-Changer for the UK's Heat Pump Industry
As someone who has suffered from a Heat Pump installati...
By DREI , 2 days ago
-
RE: New Vaillant aroTherm Plus in black - When will it come to the UK?
Hope they know what they're doing regarding paint types...
By PatrickVito , 2 days ago
-
RE: What crazy nonsense are inverter limits and why are they imposed?
I’ve also got a dual fuel Rangemaster. We originally ha...
By Majordennisbloodnok , 2 days ago
-
RE: Octopus tariffs - a quick comparison
@tim441 I’d agree wholeheartedly with that, with 2 x Po...
By Toodles , 2 days ago
-
RE: Electricity price predictions
@bontwoody Maybe one for @editor to consider whether a ...
By ChandyKris , 2 days ago
-
RE: is a home battery without an EV worth it?
You would think, but when I had my Powerwall 3 installe...
By Old_Scientist , 2 days ago
-
@mars That response surely deserves a nomination for Tu...
By JamesPa , 3 days ago
-
Specifying batteries, pv solar etc using ChatGPT
I thought I'd try to use ChatGPT to specify my requirem...
By Tim441 , 3 days ago