Home › Forums › SUSTAINABLE CONSTRUCTION, ENERGY and WATER CONSERVATION › Sustainable Energy & Energy Conservation › Looking for opinions on the Thermalux Stirling Supreme Mk3
September 25, 2015 at 11:34 pm #258296
I’ve been browsing this site for awhile, and have really enjoyed learning from everyone’s experiences. There’s a significant pool of knowledge here that’s been great to tap into.
I have a small 50 acre farm that I run cattle on. I have a standalone 10kw solar power, a biolytix waste treatment unit and a great garden and orchard that produces plenty for my small family, with chooks to come. The only sticking point is that we have gas for the hot water and cooking, and given that I have an abundance of hard wood on the property, I’m seriously thinking of swapping out the gas oven and putting a Thermalux Supreme in, but I’m having trouble finding any comments from owners as to what they’re actually like to live with. I see there’s plenty about the Esse’s from the UK, but not much on the Thermalux (or that I can find).
My plan is to have a hot water tank set up so that I can use the solar power system to heat the element during the hotter months instead of firing up the oven, and to use an induction cooktop to cook on if we don’t need to use the wood oven itself. During the colder months or on rainy days etc, I thought we could use the wood oven to cook and heat hot water. Apparently it can be set up this way, and also still give me the option of flicking over to the gas water heater if I need to.
Basically I’m really keen to hear from anyone who can tell me about what they’re like to use. What I’m really interested in knowing is how much wood it chews through when running and also when idling overnight when using hard woods (I know this will be subject to some variables, but I’d really like to get some idea), and how much heat does it generate i.e. is it like a normal gas or electric oven which will warm the house a bit, or does it really heat the room up like a space heater? Has anyone had issues with it being smokey or smoke/odours coming back into the kitchen?
The Thermalux is significantly cheaper than the Esse and Rayburns, and I’d really like to support Australian made. And that said, if it means I can swap out my gas oven and go down this track, I’d be happy with the decision (mainly because I’ve already chopped up a big pile of hardwood and built a wood shed so I don’t want my effort to go to waste!). I know there will be plenty to learn, but I reckon that’s half the fun of it.
Thanks very much.
crabyApril 22, 2016 at 2:50 am #538260hobbyfarmerMember
We got one to replace our Everhot which was worn out and drew poorly through an old chimney.
It lights easily and draws well, but the very large firebox means that to get it burning cleanly it generates too much heat, but if it runs slowly it is a smoke and creosote factory. Excellent hot water, but have to run it hard to get the oven and top plate hot. Could be because of our wood – well-dried peppermint gum.
Perhaps it’s how we use it, but need to do regular chimney cleaning (caught fire once) and the damper flap sometimes sticks shut with tar/creosote.
Significant plus- easy to clean – no difficult to reach smoke passages. In fact can lift the kettle plate and clean the damper flap when it’s running.
To get it to run a bit hotter I filled the back of the firebox with firebricks which may have helped. Until manufacturers are compelled to match the efficiency/clean burning standards that wood fired heaters must meet, I guess these ranges will not improve.
So in summary: well made and runs well, with reservations. I doubt if Esse or Rayburn are twice as good at twice the price, but be prepared to keep the flues clean, probably helped by using good wood – we may buy in some redgum.April 22, 2016 at 3:31 am #538261
Thanks very much for your reply. Its coincidental as I’m driving into Brisbane on Tuesday to look at the Thermalux as they’ve got one on display there.
I’ve got about a ton of forest red gum cut up that I’ve had drying for around 18 months. I burned some the other night in an outdoor fire and there wasn’t much smoke, but it had a really bright orange/yellow coal action that was really quite good and lasted for ages, with a few licks of blue flame as well, so I guess it burns pretty hot. I found a list of different eucalyptus woods and their individual densities for firewood purposes, and red gum is listed as having a high density than the peppermint, particularly for coal action, so you’re probably right about trying it. I’ve attached the list as you might find it helpful. Basically the higher the density, the more weight in wood is contained within a square metre i.e. you’ve got more weight of ironbark in a square metre than peppermint, because its denser. That said, forest red gum (Eucalyptus tereticornis) isn’t on the list, but when I looked it up its 1000 seasoned and 1200 unseasoned, so it’s right up the top of the list. The wood is like blocks of cement it’s so dense and hard, so I’d say its worth a look. I’ve been buying half a dozen saplings a year and planting them to keep a future supply going, but mind you my kids will be the ones using those I’d say!
In relation to the hot water, do you just have the header tank in the ceiling, or do you have an outdoor tank with a backup electrical coil in it as well, or what type of setup do you have?
When you say its hot, is it much hotter than a normal electric or gas stove when the oven is on? I’m hoping it will double as a bit of a heater in winter.
I’m going to be interested in seeing the Esse’s and Rayburns as well, as I had the same question. Can they really be worth twice the price? They look at bit flasher, but the price is pretty steep.
Thanks very much.
crabyApril 22, 2016 at 5:46 am #538262SnagsMember
I would love a a wood fired oven and looked into it.
Its only cold for 2 or 3 weeks so it doesnt justify the costs.
I would love the idea of a slow cooked meal and to run a hydronic heater,but a barbie and a reverse cycle aircon make more economic sense. (insert sad face icon)April 22, 2016 at 11:14 pm #538263LioraParticipant
We have a couple of friends with a thermalux, wet back etc and they are very happy except for the fact the unit is a bit boxy in appearance, but they are very happy with functionality. When we moved to a house with no fire place we considered the thermalux, but realised due to the size of the stove and our house, we’d have to have all the doors and windows open. Just too big in our very small house. We decided on a nectar, made in SA, and it is perfect for us, oven and fire box and can cook on the top. If your house is large I’d say go for it.April 24, 2016 at 9:36 pm #538264
I suppose that’s been my big reservation about the Thermalux i.e. it looks like I made it myself. The Esse’s and Rayburns are quite attractive units, but their price is really over the top. Our house isn’t too big, so I’ll be interested to see how much heat it puts out compared to a normal oven. I’ve been in old houses that have had small kitchens and wood burners running in those rooms, and you pretty well had to draw straws to see who got to sit at that end of the table in summer!
I’ve been really struggling to get much info from people that actually use them, so it’s been great to have a few people on this forum touch base about it. It’s been surprising that Thermalux themselves don’t seem to have much of a presence online for their product, particularly compared to Esse, but that said the company seems very helpful and has given me a lot of info in response to some questions I emailed through. I thought there’d be a lot of banter on their facebook page, but there’s not much. That said, it looks like they’re updating their website, so hopefully there’ll be more pictures etc there soon.
regards,May 28, 2016 at 11:12 am #538265
Well I finally managed to get a day to drive into town to look at the Esse and Thermalux units. It took me 3 hours to get to the shop but it was worth it to see them close up.
I’ll describe what I saw and mention the pricing differences. They had a Thermalux Supreme 3 and a Esse 990. We were looking at the Esse 905, but it’s basically the same at the 990 but with one less oven.
Essentially the Thermalux is a large iron box. On the right side is the oven, and the hot plate is like a large rectangular BBQ plate on top. The fire is on the left side, and is directly below the plate with nothing in between. The oven is on the right inside the main box, and directly next to the fire. It appears to be quite rudimentary in build e.g. the doors are held in place by little metal clips instead of latches, and it generally looks like it was made in a sheet metal shop. With the chrome top and powder coat options it would run to around $8500.
The Esse however is quite flash in appearance and design. Unlike the Thermalux, it is well insulated, and has piping that runs around inside the unit to enable a lot of control over the heat, so that the ovens are at a consistent temperature, or the hotplates. When the plate was removed, we could see the piping around inside, and all of the insulation. It re-burns the smoke to make it more efficient and produce less ash and smoke. I did some research into independent testing of the Esse units and it looks like they burn about 1.5kg per hour, which is what they advertise. The build quality was extremely impressive, and I could see why it was worth more than the Thermalux. Both will do the job of course, but the Esse was clearly the Rolls Royce on the showroom floor.
With a 315l hot water tank setup installed, the Esse 990 would run to around $20k installed. It was about $7k dearer than the Thermalux, so getting close to twice the price. The 905 which we’d get is about $5k or so dearer to the Thermalux if it’s decked out with its fancy chrome and powdercoat options. The gap is much wider when compared to the basic Thermalux Supreme.
Looking at them both, I think we’d end up going the Esse, but like I said, they both work and would do the job. The Esse 905 has a radiant output of about 3kw, which is basically the same as a bar heater on max, which is another thing I wanted to know. Essentially it would be about as hot as the gas oven we currently have. The 990 runs hotter as it has 3 ovens.
I took my forest red gum timber with me and had it tested with their moisture meter, and it’s at the high end for burn time and energy density, which apparently means longer idle burns and less soot. Esse reckons you can only empty the ash pan out once a month, and even then it should only have a couple of cups of ash. I think it works like the solo stove camp stove I have, where the smoke is recirculated through the fire again. We can run that for half and hour and it has about a tablespoon of ash left, as everything is totally burnt.
Apparently any plumber can rig up the hotwater, and the hot water systems that are installed on the Esse are made in Australia by Thermalux. It would have an electric booster in it, and I could switch back to the house gas hot water unit if I ever had to. Basically I can switch between the oven doing hot water, the solar power system or the gas hot water unit.
From cold its about 40 minutes to get the Esse to a moderate oven. They demonstrated lighting it for us and it was quite impressive how well the draw worked.
Anyway, I thought I’d write back to say how it went, and what they were like up close. Comparing them both directly I could see why the Esse costs more, but ultimately they’d both work.
regards,May 30, 2016 at 6:41 am #538266LioraParticipant
Esse is a sexy looking unit. I’d have loved one.
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