Wood based shop/home heating options

[Andy Pratt]

I'll hopefully be building my dream shop in the next year or two and I'm trying to iron out the biggest expenses now so I know how soon I can quit my current job and start woodworking (it will be a wonderful day). In that vein, I'm trying to make my plan for a somewhat unconventional heating arrangement and was wondering if anyone could offer me some advice on their experience with similiar setups.

Basics:
- The shop will be in upstate NY (no nat. gas avail in my area) and I will keep it heated 24/7/365
- My primary heat source for shop and home will be wood with a backup of electric or propane for convenience/vacation.
- I would like to heat the shop with radiant (liquid) floor heating unless there is a compelling reason not to (seems all in all the best option to me).
- I plan to keep this shop/home for the rest of my life (I'm 26 now) so longevity of the system is fairly important unless repairs are easy&cheap.
- Initial cost is immaterial as long as it produces accordant efficiency&savings in the long run

What I would like:
- Something that can heat both my house and my shop at the same time (temps in the house and shop will be similiar year round). Shop will be about 1000sq/ft home will be 18-2500 sq/ft.
- A backup system (propane or electric) that can tie in somewhat efficiently to the main heating system.
- Something that can burn a load of wood 8-12 hours (night) without re-stocking, and hopefully only need one or two loads during the day.

I've heard that I can buy a giant outdoor (well insulated) wood-fired boiler that could accomplish all of my home and shop heating needs and could have a smaller backup system tied in to keep everything above freezing when I'm on vacation. Any ideas of where to start this search or advice if you think my plans are misguided would be great. I've only got a slight clue what can solve this situation, so even the most basic advice would be great.

Thanks in advance for your help, and for slugging through the long post.

Andy

[Stephen Pereira]

Hi Andy,

An outdoor wood boiler is a good way to heat your home and wood shop. There are a few ways to go about this for your shop: install plastic lines under concrete slab, use finned copper baseboard units around outside walls, or hang unit heater from the ceiling. The infloor plastic lines work well.. just make sure they are installed correctly.. you don't want to discover leaks after the concrete is poured.

If your house furnace is forced air you can install a unit heater in your plenum or run hot water baseboard units around the perimeter of your home. You can make a unit out of 2" copper pipe to heat your hot water.. works good. The plumbing can get sort of complicated.. zone valves, manifolds, circulating pumps etc. It all depends how fancy you want to get.

I built my own boiler and ran hotwater baseboard units in my house and hanging unit heater in the shop. The boiler is centrally located between house and shop and I buried two insulated plastic water lines to each building. I built this twenty years ago when outdoor boilers were just gaining popularity in northern Minnesota. They have better insulated plastic lines today but be prepared to spend some money.

Outside wood boilers in cold climates can burn LOTS of wood.. a well insulated boiler and buried water lines will help. The boiler I built was a "tea kettle" type.. non pressurized. I believe commercial units come both ways.. there are advantages to both.

If I had to do it all over again and was building a new shop I might house my boiler in a concrete block room connected to the shop. Pipe the hot water to the house and blow the "waste" heat from the boiler to the shop. Your insurance company might have other ideas.. check with them first.

Good luck,

Steve

[Jim Becker]

Bill Grumbine is heating both his home and shop with an outdoor wood-fired boiler. I messaged him about this thread in hopes he will comment.

[Jim O'Dell]

Steve Ash did a corn boiler that sat outside and heated his house. See http://www.sawmillcreek.org/showthre...ht=corn+boiler
Start at post 13. But I doubt that corn would be the best source in upstate NY. But it did offer power feeding so you didn't have to load wood multi times a day. There was a company that had a banner ad on Woodnet at one time that sold the wood burning units. I read through their on line brochure, but haven't seen them in a while, and don't remember the company name, but I'm sure there are several out there. Maybe Steve's information on the comapny he chose will also do wood burning units. Good luck, and remember to update and post pictures when you start this project! Jim.

[Henry Cavanaugh]

Keeping in mind the energy lost in transfering heat from an outdoor unit, and community's are starting to come up with regulations on there use, because of smoke issues etc I would use a stove in the house. A previous house I had for 10 years had a woodstove on the first floor with a water jacket for hot water. The upstairs was heated by registers in the floor. The basement being underground needed no heat.

[Bill Grumbine]

Hi Andy

Jim let me know that this thread was going on, since I don't always get over here to this forum. We put a Heatmor outdoor furnace in two years ago this coming October. I am currently heating the house with it. I have the piping run to do the shop, but I have not come up with a solution (or the cash!) to install the heat into the shop, but it is coming.

We looked at a number of different possibilities for an outdoor heater, and settled on the Heatmor for a number of reasons. First, it will burn wood or coal. I am not wild about burning coal, since it requires a bit more work than wood, but it is a good option to have if the cut and dried wood supply runs low. Second, it has a forced draft, meaning it fires faster, and shuts down faster than a solenoid operated draft does. Third, the ash pan is located below the firebox, making removal of the ashes a lot faster and easier.

The furnace has a 10 year warranty, and parts are replaceable. Once other nice thing about the Heatmor over regular wood furnaces is that it is "bottomless". The bottom consists of a cast iron grate surrounded by owner installed sand, as opposed to a stainless steel floor that most of these things have. The floor is the biggest wear point of the box, and cast iron and sand have a longer life expectancy that stainless steel will.

I see a couple of issues have already been mentioned. I had a number of them raised when I was asking about these things too.

Smoke - if the furnace is loaded properly, it is going to smoke very little. It is people who are burning things that should not be burned, or using a furnace that has not been maintained properly that cause smoke problems. One man in our township was shut down for burning carpet scraps and causing an awful smell for all the neighbors. When we put ours in there were no regulations, but the popularity has jumped along with the price of fuel, so regulations are popping up.

Heat loss - I don't know of a way to measure this, but I think it is a non issue. What I do know is that it can be bitter cold here, like sub zero with the wind howling, and the furnace supplies adequate heat to keep our drafty stone house comfortable. It also supplies enough hot water for the endless showers of multiple teenagers. There is heat loss, but I think it is minimal. We have our furnace 135' from the house, since I wanted it to be by an existing structure ideal for holding wood and coal.

Work - It takes work to make one of these things go. I had all sorts of people warn me about the dire consequences of having to go outside every day in the winter! Well guess what? I like going outside every day. The only days I am not outside for part of the day is when I am too sick to get out of bed. As far as work goes, that is good for me. I get to exercise while hauling, cutting, stacking, and loading wood into the furnace. And it is free! I don't have to pay a gym or buy a machine to do it. And as far as the time it takes, again, I would have to spend that time doing something to keep from getting even fatter than I already am, so this works out very well for me.

Efficiency - If I load the stove with big wood, it can go for 12 -18 hours on a single burn. Even in the real cold weather it will go at least 12 hours. I work here on the property as well as live here, so I am usually home during the day. I burn smaller loads of smaller wood and stoke it more often. If I put too much small stuff into the stove at once, it burns too fast and creates a smelly gray-black smoke. Smaller fires during the day are more efficient and allow me to use up small bits of firewood and scraps from the shop. When burning properly, as mentioned above, the furnace is very efficient. I get a small wisp of white smoke when it is shut down, and virtually clear vapor when it is firing at full blast. Not only does this keep neighbors and officials happy, it is in my best interests because it means I am getting the most out of my fuel.

My furnace will burn logs up to 3' long, and has an opening that is 18" x 20". So, anything smaller than that, and which I can lift, gets burned. I have thrown a number of pieces in that have taxed even my strength, and I am no weakling! But boy do they burn nice! The length of burn I will get out of my wood varies depending on species, dryness, and if the wood has started to rot. The ambient temperature also affects this as well. In Oct/Nov, I can get three weeks or more out of a cord of wood. In the colder parts of the winter, I will get two weeks out of that same cord. If you have a newer house, that will offset the colder climate where you are. Our house is about 200 years old, stone, and drafty. It requires a lot of heat to keep it warm.

A lot of people are looking to these things as if they are a panacea for heating issues. They are not. They require work, maintenance (filling and cleaning for example) and they need a backup system. Ours is piped through our oil burner, and it can be set up so that the oil burner automatically kicks on if the wood fire goes out. If we are in the throes of a Nor'easter, I let the oil burner kick in until the storm is over. Then I shovel a path, and start the wood going again. If I am sick or out of town, my wife can decide to burn oil or wood, or even coal if she needs to do so. But we keep the coal for a reserve. We also have it set up so that if the power goes out, I can run the whole system off a portable generator. It requires less than 10 amps to keep the furnace, circulator, and oil burner going. So as long as I have the gasoline, I can keep the entire house warm and people in hot water for as long as I need in the event of a power outage.

If you don't mind the work, you like being outside, and you have the source for wood, it is a good choice. But it is not for everyone. If you have more questions, I would be glad to try and answer them.

Bill

[Dan Muller]

About 13 years ago my wife and I did a lot of work looking into home construction techniques for our dream home. (It has yet to be built, for a variety of reasons.) We got very interested in something called a "Hill boiler". For the life of me, I can't find it referred to by that name on the Internet. Apparently it's now referred to as a Jetstream furnace.

This is a wood-burning furnace designed to burn wood fast and clean, fed by forced combustion air. It heats a water jacket which circulates the water into a large water tank, which stores the heat. The hot water is later circulated through the heating system.

The nice things I remember about the units that were available at the time:

• Takes four-foot sticks.
• Burn a load in the morning, gives heat for the whole day.
• Very compatible with radiant floor systems, which like a lower temperature than standard hydronic systems.
• Very compatible with solar heating systems, which also like to have a large storage tank.
• Incorporated an optional oil burner for when you're away.
• Makes efficient and clean use of the wood.

Downsides:

• Not cheap.
• Not small, when you take into account the water tank.
• Used with standard radiators, you'd have to oversize them because of the lower water temperature.
• Not manufactured anymore?

I just read the whole Wikipedia article that I linked to above, and now I'm thinking it must've been more than 13 years ago! Dunno if anyone is still making these, but they sounded awfully intriguing to us at the time. When you mentioned radiant floor heating, I just felt the urge to share this fascination, though I'm not sure it's actually a useful memory anymore...

(BTW, this is my first post on SCM. Figures it wouldn't be about woodworking... )

[Ben Grunow]

Cant speak to the boiler aspect but when you build, consider using spray foam insulation and at least 2x6 studs for upstate NY. You could lower your heat requirements by half with the right insulation and window/door package. They all cost more upfront though. Figures right?

Consider some "green" building techniques to increase efficiency and reduce energy use all around. Be careful of too many new fads though as you are in it for the long haul. Sounds like its time to find a good builder who has some experience with these types of things.

Good luck.

[Greg Funk]

If you're on a reasonable size property and you don't mind a bit of upfront expense I would investigate a geothermal heat pump. They operate very efficiently and provide heat in the winter and cooling in the summer. You won't get as much exercise as a wood fired boiler but they are very efficient to run.

Greg

[Jim Nardi]

If I was designing the ultimate it would be a water jacked fire tube boiler with a burner designed to run on startup and when needed for additional heat. It would have 2 circulating pumps one to run and a spare. I'd have a small backup generator that ran on propane for the building. There are several industrial heating systems that have large hot water storage tanks something you might want to discuss with your system designer. My best guess is the ultimate power plant with building would be in the 60,000.00 dollar range.
Learing how to service your boiler and the quality of insulation is where your going to make or break the effiency of your setup. There are so many variations on ways to heat and cool your buildings your going to have some hard choices. This wind turbine and deep ground heat pump combo are interesting. So are several developement's into the cheap solar panel setup. Good luck if you narrow it down to a few post again.

[Bruce Wrenn]

Years ago,I purchased the plans for an outdoor furnace. (Google the word HAHSA.) It was a block building with a firebox. The firebox was surrounded by SAND. In the sand was a grid of CPVC pipe, through which water was circulated. The fire was stoked "hot" and the sand was heated. The heat was then transferred to the water in the CPVC pipe. By not having a "tank full of water", you could use the RV waterline antifreeze in grid. It is food grade gylcol, unlike he stuff in Chinese toothpaste. For piping, use schedule 20 PVC sewer pipe burried a couple feet down. Inside, use PEX piping, with insulation.There are many pipe insulations available, with the cheapest being the swim noddles from the dollar store. There is a "cord wood stove" that has wood inserted vertically. The wood burns at the base, with a forced air flow (fan) blowing on it. As wood burns, it drops down to feed fire. Ideal situation would be to have wood stored above furnace so it could be fed by gravity into furnace. These three ideas could be combined into one outdoor furnace.

[Andy Pratt]

Thanks for the detailed replies everyone. I've definitely got a better handle on what to look for now than I did before the thread. I'll start doing some more detailed searches and working on pricing and will probably have a few more questions soon.

Thanks again,
Andy

[Jon Shively]

I have had a Central Boiler outside wood burner for six or seven years now. All I know, how ever long it has been I have not had a heating bill since then!!!!!!!!! It is the single best investment I have made to my home to reduce my ties to a gas company.
Central Boiler now has a new stove (been out probably five years now) that has a natural gas or propane gas alternative. It is called a dual option stove. It will automatically switch to your choice (natural or propane) at a certain tempature to maintain the water temp. So if you go away, no problem, it will switch over and the house and shop will stay warm. Once home you have to mechanically switch it back to wood option, build the fire and continue on your merry way. There are stoves in this lineup big enough for your square footage. The addition on my home I installed radiant floor heat, it is the second best investment I made in my home!!