Do Hot Compost Bins Work?
An honest assessment
Written by Daniel Woodley. Fact Checked by Hannah Miller. Published to Soil & Compost on the 21st June 2021. Updated: 25th February 2023.
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Home composting has become popular in recent years, and during the Covid-19 lockdowns, many of us spent our time in our gardens, so if you’re thinking about getting started, go for it.
I did a lot of composting at my previous home and here’s what I feel the benefits are:
- Great for the environment as less kitchen waste goes to landfill or recycling centres.
- Fun and educational for children.
- It doesn’t take up much space in the garden – most composters are smaller than a wheelie bin.
- It’s much cheaper than buying compost and fewer trips to the garden centre.
- Less plastic packaging waste; you might be surprised at how many bags of compost the average gardener buys.
But what about hot composting?
What is it?
How does it differ from regular composting, and do the results live up to the claims?
My name is Daniel Woodley, and welcome to my guide to the best hot composters and how to get the most from them.
Daniel Woodley
Do Hot Composters Work?
Before I go into how a hot composter works and how it compares to a regular composter, check out the short video below from a small local group called “Norfolk Master Composters”, you can find them on Facebook here.
As you can see from the footage, this hot composter produced good quality compost at the first attempt, and the owner started this pile in January, which is a cold month.
I have experience with hot composters, and I know they produce the goods much quicker during warmer months (more about that later).
The bin shown in the video is a HotBin which you can find here.
Comparing a Hot Composter to a Regular Compost Bin
I’ve previously built both open piles, a regular bin and an insulated composter, and I can tell you the difference between the three is huge.
Simply put, an insulated composter will produce compost much faster than a cold composter or open heap.
I could produce usable compost in 30-90 days, depending on how hot the bin was, the time of year and what I put into it.
According to the RHS, a regular garden compost pile takes between 6 months and 2 years, while a larger council-run compost heap takes up to 1 year.
Commercially built composters are designed to hold in the warmth created by the decomposing matter, while an open pile or regular compost bin loses this heat much more quickly.
Pros
- Fast turnaround time. The Berkley Method to hot composting can produce results in 18 days.
- I found that less space was needed as I could empty the composter more frequently.
- Sterilisation – the heat kills off pathogens and weeds, which is a common problem with many cold composters.
- It’s fun. I was able to control the decay rate by adding fish and bone fertiliser (sped it up) or sawdust (slowed it down).
- I found that the material inside a hot composter didn’t reduce in size as much as a slow/cold composter, so I got more compost.
- I also noticed fewer flies, insects and vermin as it’s too hot for them.
Cons
- The cost – commercially made hot composters cost much more than regular compost bins.
- I live in Surrey in the UK, and in the winter, it didn’t work as quickly.
- I found myself turning the soil more frequently to aerate the contents.
- While they produce compost quickly, I had to spend more time making adjustments and being careful with what I put into it.
- Composting, in general, is easy to get wrong, and hot composting, even more so. I learnt that it’s not simply a case of chucking everything into a bin and leaving it.
The Best Hot Composter For the UK
I previously built my own insulated composter from leftover building materials, but for this guide, I conducted independent research into hot composters currently on sale in the UK, and the HotBin is my #1 choice.
Here’s why:
The HotBin currently has more insulation than any of the other hot composters I examined, and given that many parts of the UK get very cold in the winter, I feel this is important.
There are other products on the market that hold in the heat, but after looking at the thickness and quality of the insulation, I don’t feel they would hold well in cold northern winter.
The HotBin is a sealed unit, and you see how thick the insulation is in these photos:
Also, the HotBin composter looks and feels like a very well-engineered product. It’s airtight, has straps to stop the door from coming loose, has a sloping floor for liquid drainage, has a drainage hole and cap and comes with a carbon filter to capture unwanted odours.
I couldn’t find a better hot composter for sale in the UK despite looking everywhere.
Overview
The HotBin composter comes in two sizes; a 100-litre mini version and the standard 200-litre version, which is about the size of a wheelie bin.
Don’t forget that, based on my experience, you won’t need to wait an entire year to get compost, so the smaller HotBin might be your best option, especially if space is limited or you don’t create much compostable waste in your home/garden.
100-litre HotBin:
115cm high x 45cm wide x 45cm deep.
Height with lid open: 142cm.
Depth with lid open: 53cm.
5cm recyclable polypropylene insulation.
Weight: 4kg unboxed.
Thermometer.
Raking tool.
Aeration valve to control the temperature.
Biofilter to reduce odour.
Sloping internal base so any liquid funnels to the drainage cap. Waste liquid can be used as a fertiliser.
Optional stand.
3-year warranty.
200-litre HotBin:
115cm high x 55cm wide x 55cm deep.
Height with lid open: 142cm.
Depth with lid open: 63cm.
5cm recyclable polypropylene insulation.
Weight: 8kg unboxed.
Thermometer.
Raking tool.
Aeration valve to control the temperature.
Biofilter to reduce odour.
Sloping internal base, so any liquid funnels to the drainage cap. Waste liquid can be used as a fertiliser.
Optional stand.
3-year warranty.
Eco Credentials
There is no doubt that home composting is far more eco-friendly than buying compost from garden centres, but how eco-friendly is the HotBin?
Currently, neither of the HotBins are made from recycled plastic, which is disappointing. However, the ARPRO (expanded polypropylene) used in the construction can be recycled.
It’s also worth noting that the expanded polypropylene found in the HotBins is around 95% air and only ~5% plastic. Hence, there’s actually very little plastic used in the construction, which is evident in the product’s weight. For example, the Mini HotBin weighs only 4kg, including the thermometer, valve and raking stick.
Alternatives
The obvious alternative to a hot composter would be a regular compost bin, but these take much longer to produce compost and are notorious for not killing off pathogens and weeds as well as attracting vermin and pests.
The next best hot composter in the UK is the Aerobin. However, I’ve looked at this product and in my opinion, the insulation is far too thin. The company behind the Aerobin is Australian, and while this product may work well in a warmer country, I feel it would struggle in cooler parts of the country in the UK.
It may work well in the far south of the UK, but I believe the Aerobin would get so cold during the winter months that it just wouldn’t work in northern areas.
There are a couple of advantages over the HotBin, so maybe those living in warmer parts of the UK could try it:
- Cheaper.
- Larger bin options – up to 600 litres.
The Aerobin installation video is below. As you can see, it’s not as well insulated and is perhaps more suited to a warmer climate:
Conclusion and Summary
Hot composters work very well and can produce usable compost in 30-90 days.
30 days – expect bulky mulch-like compost.
90 days – expect a fine compost for pots, baskets and borders.
If you live in a cooler part of the country, I think you should choose a very well-insulated composter if you want to use it all year round.
Be aware that some foreign products are designed for different climates; they might not work so well in cooler parts of the UK.
Composting is eco-friendly and fun but can also be frustrating and I found it takes time and quite a lot of effort to learn the correct ratios of green and brown waste:
Too much brown waste, such as woodchips and larger twigs – cools the composter and can stop the process.
Too much green waste such as grass clipping, soft leaves, annual plants etc. – accelerates the process, but the lack of bulky materials can lead to sludge and slime.
I like that hot composters are sealed units that don’t seem to attract as many pests as open piles and the fact that they produce compost in a fraction of the time.
I dislike the hassle and time it takes to set it up and keep it optimal.
FAQs
What Produces the Heat Inside the Composter?
As the matter inside the composter decomposes, it produces heat. If the composter is well insulated, the increased temperature will accelerate the process.
In cooler climates, you can chuck in a hot water bottle to get the process started, but all of the hot composters don’t use any other form of artificial heat.
Should I Locate the Composter in Direct Sunlight?
I created my own hot composter, and I found that when I located it in direct sunlight, there was some slime and the process was too quick and I had to vent the unit.
Based on my experience, I suggest placing them in shade or partial shade, rather than direct sunlight.
Do I Need to Buy Compost Accelerators or Similar Products?
Compost accelerators usually contain nitrogen to speed up or kick-start the process; they are beneficial in cold, regular composters, which are notoriously slow to produce compost but I never used them in my hot composter.
Can I Put All My Food Waste in a Hot Composter?
Unlike a regular cold composter, a hot composter will break down all food waste, including those from animals.
I’ve found that the key is to not overload the composter with too much of one thing as it requires the right ratio of materials to function correctly.
This pdf from HotBin lists everything you can put into a hot composter.
Do I Really Need a Hot Composter?
Regular cold composting works just fine but takes longer, doesn’t kill off all the weeds and pathogens, and you need to be more careful with what you put into a regular composter as it could attract pests before it’s had the chance to breakdown.
While I enjoyed experimenting with my hot composter at my previous address, I also found it quite a lot of hassle and not really worth my time.
Author: Daniel Woodley
Daniel has over 18 years of experience in the construction, home improvement, and landscape garden industries.
He previously worked as a project manager and has experience in managing teams of tradespeople and landscape gardeners on both small and medium sized projects.
Daniel is also a keen gardener and enjoys growing unusual plants and tending to his lawn.
Why Trust Us? Our Experience With Hot Composters
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Daniel Woodley previously built his own hot insulated composter from leftover building materials and used it for two years, including two winters. He also conducted independent research into commercially available composters in the UK for this guide.
As accuracy is important, we asked qualified horticulturist Hannah Miller to review and fact-check this guide.
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