Renewable Heating Hub Heat Pump Forums

Search with Wattson
Forums
Sustainable Sidetra...
Energy Storage
Outdoor Battery Sol...
 
Notifications
Clear all

Joining the Renewable Heating Hub forums is completely free and only takes a minute. By registering you’ll be able to ask questions, join discussions, follow topics you’re interested in, bookmark useful threads and receive notifications when someone replies. Non-registered members also do not have access to our AI features. When choosing your username, please note that it cannot be changed later, so we recommend avoiding brand or product names. Before registering, please take a moment to read the Forum Rules & Terms of Use so we can keep the community helpful, respectful and informative for everyone. Thanks for joining!

Outdoor Battery Solutions?

 
Page 2 / 2
Energy Storage
Last Post by Batpred 4 weeks ago
16 Posts
5 Users
6 Reactions
692 Views
RSS
 EtchedPixels
(@etchedpixels)
Estimable Member Member
Joined: 1 month ago
Posts: 89
08/06/2026 4:53 pm  

VAT Notice 708/6.

It's not as far as I am aware ever mentioned MCS and indeed many of the things it covers are simply not even MCS covered in the first place (eg draught strips).

For a vat registered operation the paperwork should be no more than usual for VAT. For a not vat rated operation I don't know but I doubt it's fun if it's even possible.

 



   
ReplyQuote
Batpred
 Batpred
(@batpred)
Noble Member Member
Joined: 2 years ago
Posts: 1066
08/06/2026 5:37 pm  

@etchedpixels 

Thank you. From what I see, it covers all building trades. VAT registered contractors or subcontractors can supply and install items in the list free of VAT. 


8kW Solis S6-EH1P8K-L-PLUS hybrid inverter; G99: 8kw export; 16kWh Seplos Fogstar battery; Ohme Home Pro EV charger; 100Amp head, HA lab on mini PC


   
ReplyQuote
 Old_Scientist
(@old_scientist)
Honorable Member Member
Joined: 2 years ago
Posts: 452
09/06/2026 12:05 pm  

Have you modelled the costs of switching tariff?

We have solar, battery and ASHP. Like you, our peak winter usage can approach 50kWh per day. We are able to cover this with a single Tesla PW3 battery at 13.5kWh (installed outdoors in the rain) by using the Octopus Cosy tariff which has 3 cheap rate charging slots.

The Cosy cheap rate is more than your current EV tariff, but we need a fraction of the battery capacity as we are able to recharge the battery 3 times per day so each recharge only needs to last 6h until the next available cheap rate slot. It also works well ion summer as a single 13.5kWh PW3 nicely covers a full day's usage (~12kWh) in summer, even if there is absolutely zero solar. We do not have an EV in that mix.

So for us the question was/is simple - would the cost of additional batteries be offset by moving to a cheaper overnight tariff (we could pretend we have an EV on regular Octopus Go). To achieve that, we'd need two or three PW3's so for us the smaller (cheaper) battery capacity works out better and gets us to the point of having zero bills (export in summer offsets import in winter)

There is also the risk that you may not see a return on capital if cheap overnight EV tariffs end (or prices normalise) as you now have large battery capacity that you can no longer cheaply fill.


This post was modified 4 weeks ago by Old_Scientist

Samsung 12kW gen6 ASHP with 50L volumiser and all new large radiators. 7.2kWp solar (south facing), Tesla PW3 (13.5kW)
Solar generation completely offsets ASHP usage annually. We no longer burn ~1600L of kerosene annually.


   
👍
1
ReplyQuote
Batpred
 Batpred
(@batpred)
Noble Member Member
Joined: 2 years ago
Posts: 1066
09/06/2026 6:48 pm  

For us, adding a 16kwh battery means a heatpump can reduce energy costs by 50% (instead of a 10% drop(. And since our £/kwh is significantly lower than Tesla's, it is a simple decision. 


8kW Solis S6-EH1P8K-L-PLUS hybrid inverter; G99: 8kw export; 16kWh Seplos Fogstar battery; Ohme Home Pro EV charger; 100Amp head, HA lab on mini PC


   
👍
1
ReplyQuote
Page 2 / 2
Forum Jump:
  Previous Topic
Next Topic  
Topic Tags:  Solax (1) , EcoFlow (1) , IP56 (1) ,
Share:

SPONSORS

Join Us!

Installer Finder

Degrees of Separation

Latest Posts

SPONSORS

Click to access the login or register cheese
Protected By
Shield Security PRO