Most aspects of firewood burning are about trading one advantage at the expense of another and so there is an infinite number of "right" choices. Firewood in a single row, split, 16" long, off the ground, in the sun, in Arizona... will dry the fastest. A pile of 24" long rounds on the ground on the Pacific Northwest Coast... will dry the slowest. My six rows are 4" apart, inside a shed, half rounds, on pallets, with only one small window in one of three walls (overhead doors on the fourth wall), and maple rounds in the middle will dry to below 16% moisture (dry basis) in three years, red oak 18%. My air flow is low but the building keeps the humidity low. I tried drying wood outside but shade and weather kept my wood above 20% moisture. Moving the wood inside after two years outside would work but moving 25,000+/- pounds twice is the trade off. Holz hauzen has an advantage for some folks but not for me. Can the wood dry enough in a holz hauzen? Yes, it dries in the deepest darkest section of my pile. Is there a way to get wood drier? Yes, but I am happy with my six rows inside just like those who have holz hauzen or... Actually, if I do not get creosote in my chimney and do not run short of dry firewood then I do not have a reason to change my system.
Well at least he knows what works for him. Like he said it depends on what part of the country you live in and what size the splits are and what type of wood it is. I can stack in single rows outside no cover at all and have wood down to 15%. Here there is no humidity, lots of wind, and sun.
The issue I was trying to show was conditions vary widely: there are many different ways to dry wood (split versus round for example), many different priorities (to move wood or not for example), climate, and many different wood specie. Holz hausen could dry wood well with conifer wood in a cold, windy, snowy, low humidity climate but be a poor choice in a warm, wet, and humid place with maple wood.
Just realized another reason I do holz hausen , is there isn’t a need for squared off bark shaved splits for cribbing or stacking. I cut at 24 inches, and would be longer if I had a larger splitter. My haus are not pretty, they serve a purpose. After a couple circles, I lay a row of flat splits around the radius to ensure the splits continues leaning inward. I can have all manner shapes and sizes of splits, and they are stacked solid and high. Usually around 6.5 feet one example I saw, was after a guy completed his, he made an additional “row” around it. ingenious way to place a surplus of splits when you don’t think you do t have enough to complete another haus as far as the chimney effect, that has been experimented with and discussed. I do t doubt the airflow helps drying. Better than what we think of as traditional stacks- a lot of variables come in to considering
I’m really surprised that there has been no discussion of the Bernoulli effect, boundary layer separation and laminar flow of air with respect to round versus square stacks as well as space that is allowed between stacks and stack height…. When considering airflow, there is a distance between the stacks that is optimal (relative to height and area of the stack) as that distance allows for maximum acceleration of air due to a fixed mass of air moving through a smaller space. Less than that optimal distance and the the majority of the air would just flow around and over the two (or more) stacks.. greater than the ideal distance and the air would not accelerate as much. Think about the effect of tall buildings in a city that cause wind speeds to increase as the air flows through the city. As for laminar flow, that is what is required by an airplane wing ( or helicopter rotor or propeller or sail) to generate lift. As the air is flowing around your stacks, and as it speeds up due to the Bernoulli effect, it is generating a lower pressure thus pulling air out of the stacks.. to generate this lift, the air must move smoothly across the surface without significant disruptions. With a round stack, the flow would be smoother than with squared off stacks. With square stacks, you will have the boundary layer (which generates the lift in laminar flow) separate from the outside of the stack resulting in airflow eddies which slow the airflow as it is disrupted and ultimately minimizes the pressure reduction that would produce the lift that would draw moisture laden air out of the stacks…. Rather than do all of the calculations for all of this to figure out how to optimize the airflow to maximize these effects, I just stack my wood as the terrain allows, wait at least 3 years, and then burn it.
I built one. Didn't enjoy it in any way - wasn't for me. Would much rather have wide space between my stacks like I have in the picture below.
A holz hauzen will transfer a good deal of air through it during daylight hours. All the way around, the hauzen will pull in air through the outer ring(s) of splits, all moving toward the center and up to exit the top / center of the hauzen. Air circulation may be reduced as compared to windrow stacking but the upside is that the hauzens get much warmer during daylight hours. The first couple I stacked I tossed a thermocouple in near the middle and it was very impressive how warm they got during the day, especially on already warm- to- hot summer days. I believe the most important factor in drying wood is temperature rather than air movement, and H.H.'s seem to be very good at that. The best example would be kilns used to force- dry wood, lots of heat but minimal air circulation. Temperature at the core of the splits is the key to driving out the moisture, and any water introduced from outside, such as rain, cannot penetrate the splits anywhere near the center. If it is desirable to dry wood as quickly as possible, I would suggest covering the entire hauzen with clear plastic, leaving a 2' to 3' hole in the center of the top. They will get almost amazingly warm during the day, drive off a lot of moisture and that moisture will leave the hauzen in the form of vapor going up, and condensate traveling down the plastic when the sun goes down. Covered, the wood will remain warm for a long time after the sun goes down and so greatly extending the drying time of the wood in a 24 hour cycle, as compared with stacked but uncovered wood which cools down quite quickly after dark..... due to the air circulating through the splits. All of that said, I do not have any actual data, other than the internal temps., as compared to normal row stacking. But the advantage to me is not how fast they dry wood but rather the compact nature of the stack- 8 or 10 cord of wood can be stacked in a surprisingly small space. They may take a bit more time to stack but I believe that is offset by the fact that they are stacked in one place and there is very little walking involved in stacking and breaking down the stacks, again as compared with stacking in windrows. In the end, I think the differences are really pretty small and it is simply not a big deal. The key getting decent firewood is far more based on time sitting outside than any particular method of stacking, again IMO of course. The real issue is trying to burn wood before it is dry enough and that is a gigantic step backwards regarding getting the most heat out of firewood. The time outside easily beats any and all other variables such as stacking method IMO.
I do not. Just stack the sides so that they are the correct angle to the vertical, which will mean more angle on the low side and less angle on the high side. And of course to bring the hauzen to a level height, more splits on the low side and gradually fewer splits as you go around the hauzen. You could 'shim' the pallets up to horizontal but that sounds like a PITA coupled with bucking the pallets so they will carry quite a bit of weight. Insufficient blocking of the pallets is just going to result in an unhappy hauzen and a more unhappy hauzen owner.
