I’m moving in at those temps!
If I’m feeling v generous, I’ll bump it up to 16.5 on a really cold night. Never gets put on during the day
1 Like
Maybe I should clarify…
… is only when most of the family is home. When we’re at work/school, it’s set to 12. The Nest is really good at auto-scheduling and ramping up to temp for when someone ‘usually’ gets home. And ramps up quicker if there are any surprise homecomings (when set to do so).
Looking back again at the sheer costs involved with gas 10 years ago, that thing paid for itself during the first 12 months - a highly recommended piece of hardware.
3 Likes
Oh I got that, I WFH but am a little tight too put it to that. Each to their own, of course
1 Like
I haven’t posted the specifics about my set up anywhere yet so here are some details;
In Feb 2019:
- 2.2kW of solar installed
- Cost approximately £3.5k including installation
- Pretty sure you can get more solar than this for that kind of money nowadays as panel efficiency has improved.
- At the time, IKEA had a partnership with a company called SolarCentury who did our installation, but I don’t think they do that anymore.
In August this year;
- I went with the myenergi ecosystem
- 5kW Libbi Inverter
- 10kWh Libbi Battery
- Zappi for EV charging
- Cost approximately £10k including installation.
- To install I found an electrician with experience doing battery installs that covered my region. Try to find one with MCS certification as that will make it easier to get paid for any energy you export.
The myenergi Libbi is an expensive option to be honest. The GivEnergy All-in-one I think is the best value for money at the moment, and supports a “gateway” that allows it to run the entire house off-grid if the grid goes down. The Libbi only supports a single circuit off-grid.
If you’re interesting in going down this route… here are the main factors I think you should consider;
For sizing the system;
-
kWh requirements per day - how much electricity does your home use in a typical day. Usually this is somewhere between 5-10kWh. You ideally want a battery size that will more than cover a full days electricity usage. If you plan to use more electricity for heating in the future, your electricity usage will increase so you may want to factor that in. Also keep in mind some systems are modular/expandable. I’ve bought 10kWh now, but I intend to add a further 10kWh in the future, and made sure my installer was aware of this so that they laid out the system with space to accommodate future expansion.
-
Max kW output requirements - this refers to the throughput of the battery and basically determines how much power can be pulled from it at once (also referred to as the max charge/discharge rate). I recommend maximising this as much as possible to avoid pulling from the grid when multiple appliances/electric heaters are running at the same time.
-
off-grid functionality - different systems have different levels of off-grid capabilities. For ultimate peace of mind in the event of an apocalyptic event, try to find something with full instantaneous grid back up. Otherwise, just having a single circuit with some sockets available in the event of a longer term blackout might be fine. Depending on how prone to power cuts your area is, I don’t think this should be a deal breaker personally. You can get a relatively cheap UPS to prevent your internet/PC from going down if you have occasional sporadic short term power cuts.
For setting a budget;
-
Annual utility bill - Your annual utility bill represents the absolute maximum ceiling on your possible savings per year, so its worth keeping this figure in mind. So if your annual utility bill is around £2k. £2k per year is the absolute theoretical ceiling on your possible return on investment. In practice, your savings will be some fraction of this annual utility bill figure depending on how much of your usage gets covered by solar (free), how much is covered by off-peak costs (usually around 30% the cost) and how much of your gas usage can be replaced with electricity provided by the battery (either for free by solar or off-peak elec).
-
Exports - Depending on how you size your system, you could go down the path of buying cheap and exporting at a good price to fast track your returns.
-
Longevity of the system - If you’re in your forever home and think you’ll keep the system for 20+ years, then you’re more likely to see financial benefits long term
For managing the system once its in place;
-
MyEnergi app gives control over when the libbi charges. The rest of mostly handled automatically. Pretty sure other systems have similar apps.
-
Home assistant can pull state of charge from the libbi system. So I’ve set it to send me prompts if the battery gets low so that I can change my behaviour accordingly. Still exploring other ways to automate things, as it starts to get even colder, I’ll probably set some electric heaters to automatically run if the battery state of charge is above a certain threshold and there is a certain amount of solar available.
There is a great youtube channel that covers all of this kind of stuff in more detail: https://youtu.be/x83t1iCMXxw?si=gqONzWqPVm7jDgOk
He also has an online tool that lets you play around with potential system sizes etc to get a sense of how it changes the impact; Solarazma - Daily Solar Modelling Utility
5 Likes
Recap of my energy usage for 2023:
- 10kWh battery installed in August '23
- 58% increase in overnight electricity usage (compared to previous year)
- 24% reduction in gas usage but 10% increase in gas cost
My rate for gas came down in recent months but remains nearly double (6.7p/kWh) compared to start of '22 (3.7p/kWh). My rates for Octopus Go tariff changed in Nov '23. Day rate reduced from 40p/kWh to 31p/kWh, night rate increased 7.5p/kWh to 9p/kWh.
10kWh libbi battery installed in Aug '23. Started using portable electric heaters to reduce our gas usage in Oct-Dec (using cheap rate battery usage to keep average unit electricity costs low). Battery has kept £/kWh low since install in August.
2.1kW solar installed in Feb 2019. It generated 2,233kWh in '23.
The system is still working great, but its definitely too small and will struggle to charge the 10kWh battery during Spring/Summer/Autumn. Considering a solar upgrade for '24.
Increasing proportion of our energy comes from electricity rather than gas as we use the battery for some small scale heating.
Average daily winter electricity usage closer to 20kWh than 10kWh… battery upgrade to 20kWh maybe?
Energy goals for '24 include reduce gas usage, get on export tariff, continue to research heat pumps, solar upgrades & battery upgrades. Plus RippleEnergy’s Derril Water solar park should come online by end of 2024 (hopefully)!
I tweeted this here too: https://x.com/DrLewisPearson/status/1742196081306247333?s=20
4 Likes