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AWS
AWS Lambda Durable Functions
Lambda functions work best for short lived, compute intensive tasks. An individual Lambda invocation is limited to 15 minutes at most. You pay for the time the function is running, including when it’s waiting for IO to complete. If the function fails, you will need some external process that retries it later. Lambda Durable Functions address these weaknesses.
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AWS
AWS re:Invent 2025
Once again, I spent the week after re:Invent gorging on YouTube videos at 1.5x speed. I’m using the same approach as last year to find more nuggets of gold and less corporate filler. That is, get a list of new announcements from the keynotes, then look for technical sessions on the interesting stuff. Finally, look for technical presentations from speakers I know are good.
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Gear
Kia e-Niro 12V Battery Drain
We’ve had our Kia e-Niro EV for five years now. Early on, there were a couple of minor issues with the heater and collision avoidance radar which were sorted out under warranty. We had to replace the 12V battery two years ago. Apart from that, it’s been trouble free.
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Gear
Home Assistant
Heat Pump Cold Weather Performance
We had a cold snap here in the UK. Over a few days, temperatures dropped from consistently over 10°C, to days at or below freezing. Perfect weather for dialing in a heat pump.
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Home Assistant
Home Assistant: Kiosk Mode and High Frequency Updates
We recently had a Vaillant heat pump and Heat Geek NanoStore installed. The NanoStore contains a small amount of hot water which should be just enough to meet demand until the heat pump can kick in and ramp up to full power. Currently the hot water runs out after five minutes while the heat pump takes ten minutes to reach full power.
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Gear
Heat Geek NanoStore
A few weeks ago I described our heat pump installation, which included a mystery hot water system. The mystery hot water system, as some of you already guessed, is a prototype Heat Geek NanoStore.
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Gear
Home Assistant
Open Energy Monitoring
I touched on Open Energy Monitoring briefly when talking about my heat pump install and Home Assistant integration. It’s worth a deeper dive.
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Home Assistant
Home Assistant Heat Pump: myVAILLANT, Emoncms and Met Office
Now that we have a heat pump up and running, the obvious next job is to get it hooked up to Home Assistant. Our heat pump is a Vaillant AroTHERM plus. A quick search of the Home Assistant Community Store turns up the myVAILLANT integration, which uses the same API as Vaillant’s myVAILLANT app.
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Gear
Vaillant aroTHERM plus 7kW Air Source Heat Pump
Like many houses in the UK, we rely on a gas combi boiler for heating and hot water. I know that continuing to burn gas is not sustainable in the long term. However, I couldn’t see the point in switching while the grid is still burning gas to generate electricity.
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Home Assistant
Home Assistant: Concurrency Model
I like to think of myself as a computer scientist. I want to know how things work. Then I want to understand why they work that way.