High air source heat pump running costs – Vaillant AroTherm Plus
Hi everyone, I'm looking for some advice please and have seen that there are some very knowledgable people using this forum. One month ago we moved into a new build house which has underfloor heating throughout the ground floor and radiators upstairs. The property has a large number of floor to ceiling glazed windows, but a high B rated EPC. The primary heat source is a air source heat pump, and the running cost for the first month appears to be very high - especially since it has been so mild. I will try to include all the details here in the hope that someone can provide an insight into our setup and what might be done to optimise it.
EPC details
- 276 square meters
- B rated (86 score)
- All scores "very good", except:
- Hot water "good" from main system
- Airtightness "average" - air permiability 9.9m3/h.m2 as tested (the three and two should be superscript)
- Primary energy use for propert is 58 kilowatt hours per square meter (kwh/m2)
- Estimated yearly energy cost for the property = £1001 (presumably this is based on gas?)
- Space heating 14994 kWh per year
- Water heating 2425 KWh per year
Current electricity usage (last month)
- Day rate = 1761.1 kwh
- Night rate = 579.7 kwh
- Total = 2340.8 kwh
- Average daily usage during December = 70.93 kwh per day (today's usage is 112kwh!)
Installation details
- Airsource Heat Pump Model - Vaillant ecoTherm Plus VWL 105/6 or 125/6 (not sure which)
- uniSTOR HP
- Buffer cylinder VPS R 100/1 M (I think)
- Controller multiMATIC VRC 700/4
- Heat Pump control interface module VWZ AI
- Weather compensated system control VRC 700/6 - I am not sure whether this is optimally setup because the rep indicated it could have been done differently, with a full Vaillant system rather than the themostat setup used. It looks to have just one zone configured and DHW. The temp is set to 26.0 degrees and set back to 26.0 degrees. See image of the big number on the panel the temp is normally around 16 degrees whenever I've looked - is this the flow heat? The DWH is set to 50 degrees. The water always seems to be hot enough. Is it correct for the weather compensated system control to be in the insulated area of the garage?
- VWZ MWT 150
- Six heating zones, five downstairs and one for the whole of upstairs. They are controlled using Heatmiser Neo2 Thermostats.
- Thermostats have been set to 20-22 during the day and around 17 at night depending on the room. The upstairs stat rarely seems to reach temperature (note large glazed windows on all sides and high ceilings)
- There are manifolds for the zone heating in the garage (boxed in) and the understairs cupboard.
- The system is installed in a store room section at the rear of the garage which I assume is reletively well insulated for this purpose, but definately not as well insulated as the house itself.
- My neighbour has a very similar setup (two similar new build properties are sited next to each other) in a slightly different house design and has experienced similar high levels of consumption.
Other information:
- I noticed water pooling on the plaform built for the unit (after raining) - I will flag this to the installer, might this impact performance?
- I have noticed some draughts in the house that need addressing, but can't believe this is the root cause.
If anyone can offer any advice about how to maximise efficiency of our system I would be extremely grateful because this is currently costing well over £400 per month which is significantly higher than expected, and we're still on a fixed tariff and it's not been that cold yet! We are in contact with Vaillant and any information that might help inform discussions will help a lot.
Happy to provide further information as required. Many thanks in advance.
I'm sure @derek-m will help you with the technical details. However, although my house is smaller than yours at 160m2, its heat requirements are similar because it's older. My average in December is 25.5kWh/day to heat the whole house to 21C for 19 hours/day. As long as the design of the system is sound you should be able to improve on 70kWh/day.
If the EPC is correct, your heating requirements are c. 15000kWh/year. You should normally need 15% of that in December, say 2300kWh. Even at a COP of 2.3, that's 1000kWh/month consumed; a lot less than you're using.
A question; how much hot water do you use?
Hi @webcmg
I have been searching for a manual that details how to check and set the weather compensation curve, but have not been able to locate one.
Unless you have a manual that shows this information, then I would suggest that you ask your installer to demonstrate how the weather compensation has been set on your system, and how it can be adjusted if necessary.
I have a 5KW aroTHERM plus.
Manual:
My settings (desired temp 20.5 / setback 20.5) System on 24/7
Adaptive heating curve: OFF
Heating Curve 0.6 (Temp Mod)
Min Flow Temp 20 / Max Flow Temp 45
Domestic hot water 48C
Cylinder boost offset 8K
3 bedroom detached new build, my unit also pools water below it.
HTH
Posted by: @kev-mI'm sure @derek-m will help you with the technical details. However, although my house is smaller than yours at 160m2, its heat requirements are similar because it's older. My average in December is 25.5kWh/day to heat the whole house to 21C for 19 hours/day. As long as the design of the system is sound you should be able to improve on 70kWh/day.
If the EPC is correct, your heating requirements are c. 15000kWh/year. You should normally need 15% of that in December, say 2300kWh. Even at a COP of 2.3, that's 1000kWh/month consumed; a lot less than you're using.
A question; how much hot water do you use?
Thanks for replying Kev. This is very reassuring. We don't use a great deal of hot water. There are two of us in the house and we normally have a reasonable length shower each day.
Posted by: @spdtdlI have a 5KW aroTHERM plus.
Manual:
My settings (desired temp 20.5 / setback 20.5) System on 24/7
Adaptive heating curve: OFF
Heating Curve 0.6 (Temp Mod)
Min Flow Temp 20 / Max Flow Temp 45Domestic hot water 48C
Cylinder boost offset 8K3 bedroom detached new build, my unit also pools water below it.
HTH
Thanks, what is the function of the set back temp and cylinder boost offset?
Posted by: @spdtdlI have a 5KW aroTHERM plus.
Manual:
My settings (desired temp 20.5 / setback 20.5) System on 24/7
Adaptive heating curve: OFF
Heating Curve 0.6 (Temp Mod)
Min Flow Temp 20 / Max Flow Temp 45Domestic hot water 48C
Cylinder boost offset 8K3 bedroom detached new build, my unit also pools water below it.
HTH
Also what's your target flow temp set to please? Also by 24/7 should I update this in the Time Programmes menu? Currently set to 06.00-22.00.
My heat curve was set to 1.1, now changed to 0.6
-
VDI 2035 heating water specification
1 day ago
-
Installing your own ASHP - DIY
2 weeks ago
-
New Installation - Grant Aerona 3 + 210L Hot Water Cylinder
3 months ago
-
Volumiser placement in Vaillant Arotherm + system?
4 months ago
-
How can I programme a setback for my Samsung Gen6 8kW heat pump?
5 months ago
- 25 Forums
- 1,513 Topics
- 31.8 K Posts
- 16 Online
- 1,283 Members
Join Us!
Latest Posts
-
RE: Additional Battery v Wind Turbine v Ripple
I should add, being an investment, the value of your in...
By Old_Scientist , 4 hours ago
-
RE: Ecodan - flow rates, sensors, settings
Achieving an accurate flow measurement is probably the ...
By Derek M , 7 hours ago
-
RE: Ecodan ASHP - How to optimise my set up?
Again, thank you for another thorough post, @derek-m - ...
By rhh2348 , 9 hours ago
-
RE: Delivering a smart and secure electricity system: government consultation
@Transparent.Now that I am represented by a new MP I th...
By IanMK13 , 11 hours ago
-
RE: Vaillant aroTHERM plus not level or flat - what base is best under an external unit?
Similar thread here
By Johnmo , 12 hours ago
-
RE: VDI 2035 heating water specification
Been looking and it seems a good little project. Ever...
By Johnmo , 1 day ago
-
RE: Do I accept an ASHP and Solar Panel retrofit under the HUG 2 scheme?
Will do. I'm currently waiting for another survey / vis...
By dssr , 2 days ago
-
The company that did the borehole were expecting us to ...
By Johnmo , 2 days ago
-
-
RE: The Misquote That Ruined the Heating Industry
@abernyte manufacturer training is pretty average. They...
By Mars , 2 days ago
-
-
RE: ECO4 Scheme and EPC ratings
@mellow Thanks. Given there is a scheme requirement to ...
By Old_Scientist , 3 days ago
-
RE: Do I just go with the lowest quote for my heat pump?
@jancold To me its a no-brainer then, a max 40C flow te...
By bontwoody , 3 days ago
-
-
RE: Heat Pump Books Beginners – Bodge Buster & From Zero To Heat Pump Hero
@editor Presumably he had some good weather Compensatio...
By Toodles , 4 days ago
-
RE: New Vaillant 7kW aroTherm ASHP or oil boiler dilemma/decision??
Storage capacity really is dependent on storage tempera...
By Johnmo , 4 days ago
-
RE: HP Cycling, Expected or Undesirable
Just a little update. I ordered a longer shielded twin ...
By bontwoody , 4 days ago
-
RE: Domestic hot water timer doing crazy things on my Grant Aerona3 10kW air source heat pump
Thanks @allyfish for the pics and info. Spoke to the in...
By Mellow , 4 days ago
-
RE: Aira Heat Pump: Stylish Scandinavian Heating
It's been a busy day for calls and emails from Aira. I ...
By MikeH , 4 days ago
-
RE: Heat Pump Servicing & Maintenance – Good Value or Rip-Off?
Hmm. A bit of a nuanced answer, methinks. As I've alr...
By Majordennisbloodnok , 4 days ago
Latest Topics
-
Ecodan - flow rates, sensors, settings
By rhh2348 10 hours ago
-
Replacing mains water with well water
By Johnmo 2 days ago
-
Additional Battery v Wind Turbine v Ripple
By bontwoody 2 days ago
-
By jamespipe 3 days ago
-
VDI 2035 heating water specification
By Johnmo 3 days ago
-
Do I just go with the lowest quote for my heat pump?
By Jancold 5 days ago
-
The Misquote That Ruined the Heating Industry
By Alec Morrow 5 days ago
-
Battery Storage Wiring Gauge Question
By Puff 6 days ago
Members Online
No online members at the moment