Keeping the HOTBIN Hot in Winter
THE HOTBIN IS CAPABLE OF WORKING AT 40-60C ALL THROUGH WINTER.
Even when the outside temperatures of falls to 5˚ F (-15˚C). To achieve this, you will need to:
- Add waste regularly – at least once a week
- Add at least 5Kg/week (2 small, or 1 large caddy)
- Ensure you add lots of shredded paper (or corrugated cardboard) in with your food waste
- Re-start your HOTBIN if your waste drops below 68˚F (20˚C) (i.e. use the ‘kick start’ hot water bottle)
Not all customers will achieve hot composting over winter as they do not have enough waste. It’s good if you do but don’t worry if you don’t as you will be able to kick start hot composting when you start to get enough waste.
To understand why, you need an appreciation of the laws of nature that govern how the HOTBIN and bacteria work:
- Hot things cool down – the insulated walls slow the rate of heat loss, they do not stop it
- To keep hot, you need more energy going IN (food to generate heat) than the heat (energy) coming OUT, i.e. lost due to cooling
- Bacteria work faster, and hence generate more heat, at higher temperatures. They work very slow and almost not at all below 41˚F (5˚C). Cold waste with cold bacteria are unable to generate enough heat to ‘warm up’ a cold bin in winter – they need a little help via a ‘hot water’ bottle to give them warmth to which allows them to get active and generate their own heat.
- A HOTBIN in an exposed windy site (e.g. middle of garden) will cool faster than one in a sheltered position (e.g. behind a wall). A windy location requires more waste.
If the HOTBIN is running at 104-140˚F (40-60˚C) it will carry on working when it snows. Snow that falls on the valve is melted by the hot air leaving the valve. There are limits – so watch out for exceptionally heavy snow (like 5cm) as you may need to brush this off to keep the valve clear.
If your HOTBIN is luke warm 68-86˚F (20-30˚C) then there will not be enough hot air rising out to melt the snow – you will need to wipe snow off the valve.
See the attached photo – we have two HOTBINs permanently on test at HQ. At this point in time one is running hot and the other has cooled down. Last night it snowed about 1 in. (2cm).