When we bought this property, one of the things on the "needs to be replaced soon-ish" list was the water boiler in the old house. The water boiler was very old. The advice we received from every HVAC person who looked at it was: "I'm afraid to touch it. Consider yourself lucky it lasted this long".
It was time to evaluate our options. The easiest option would have been to simply replace the existing boiler with another boiler of the same type. But we decided we should at least consider alternatives, including:
- electricity
- oil
- propane/natural gas
- geothermal
- wood
Electricity
Although electric boilers for on-demand domestic hot-water are all the rage right now, heating a whole house with an electric boiler still remains very (prohibitively?) expensive.Our research also indicated that although our property is already fed with a 200A service, there's a very good chance we would have needed a larger service for a primary, whole-house, hot-water boiler. Getting the utility company to bring in a new feed (or updating our existing feed) would not be cheap. Plus, we would also need lots of new inside electrical work as well.
So getting this work done would be expensive, and the on-going costs of running the system would also be very expensive as well.
Oil
On the one hand we already had oil tanks in place. Simply switching the old water boiler for a newer one would have been the easiest way to go. But on the other hand, the oil tank in the old house was just about due for a new certification, and it was very likely our insurance company would have insisted on us switching to a double-walled tank. If the insurance company insisted that the tank in the old house be switched to a double-walled tank, then it was inevitable they'd eventually want the tank in the new house switched as well when its re-certification came due (in about 5 years). So in our case, continuing with oil would have required us to replace both of our oil tanks, and one furnace.If you've ever lived in a house that is heated with oil you'll know that oil can be smelly. Even if your system doesn't have any leaks, even if everything is shiny and new... just having oil in the house is going to emit some smell, and it isn't a pretty smell.
Regardless of whether your tanks are single-lined, double-lined, or have 5 liners, there is always a chance of an oil spill. Maybe the person filling the tank messes up and overfills, maybe a tank gets knocked off its legs, maybe a connector comes loose, maybe the hose going from the tank to the furnace gets punctured... anything can happen. From what I hear, oil spills are very nasty: everything gets ruined, and the cleanup is long and costly. Although spills are rare, there's always the possibility. Plus, no matter what tank you have, it still needs to be re-certified every couple years, and every couple years the insurance companies like to change their minds on what sort of tank you must use.
Although oil is, relatively, the easiest route, in our case we'd still have to replace our tanks. Plus, do we want to continue living with the smell of oil, the constant tank re-certifications, and the possibility of a nasty spill?
Propane/Natural Gas
For most people, switching to a gas-fired boiler is the no-brainer solution. Most HVAC people will push customers towards gas: it's what they know, so it's what they recommend. Currently, gas-fired furnaces are probably one of the most popular technologies in my part of the world.
However, in our specific case, there are no gas pipes going past our house on the road. All the roads around us have gas, but not ours. When I called the gas company to ask if/when our road would get service they said there just weren't enough houses on our street to justify putting the lines in. So if we wanted to switch to gas we'd have to get our own tank, which involves having to choose a size of tank, getting it filled regularly, and (most likely) paying a yearly rental.
Gas isn't a bad choice. We actually had decided we were going to go with gas but were turned off by the lock-in. The tanks are very expensive to buy, and they must be replaced every X years, so it makes little to no sense to actually buy a tank. This means you have to rent. However, the moment you rent a tank from someone, you're locked into buying all your gas from that person. You can't get one company to rent you a tank, then get someone else to fill it. It became exceptionally messy trying to compare all the different companies, prices, and options. One company, for example, would charge nothing for the install and next to nothing for the yearly rental, but their gas prices were always 10c more than everyone else. Another company charged huge fees for the install, but their gas prices were the cheapest by 2c. Of course gas prices fluctuate wildly, and every company changes their prices at random times. Just because one company has the cheapest gas prices today doesn't mean they'll have the cheapest, or even good, prices next month.
Although this is probably the choice most people would make, in our case we'd have to replace two furnaces (if we wanted to get completely away from oil) and, since there aren't any gas lines along our road, comparing gas tanks and pricing was frustrating.
Geothermal
In-ground heat pumps have been popular for a couple years and most people seem pleased with them. They seem to provide a lot of "I'm saving the planet!" karma, but little else.
For one thing, they have one of the highest initial costs. Then, because the temperature delta is so low, very large volumes of liquid needs to be pumped through the system very fast. This means larger pumps, using higher amperages, which leads to higher electric costs to keep the system running.
Not to mention, there are a disturbingly large number of reports of people paying tens of thousands of dollars for a system, and still having to supplement with something else on those really chilly nights! Thankfully extra chilly nights are infrequent and don't last for too long, but it seems strange to pay so much for a heating system that only works most of the time.
Wood
Between electricity, oil, gas, and wood: heating with wood can be many times cheaper than the others. This is especially true if you are able to source and process your own wood. However, if all you can manage is to buy small quantities of seasoned wood, then wood has less of a cost advantage over other sources of fuel. But if you have the space and time, coupled with a little bit of planning, you can buy "green" wood and have it delivered early in the cycle so it seasons on your property. This is significantly cheaper than having to buy seasoned wood.
But wood has its downsides. Wood is a lot more work, and it's messy.
But wood has its downsides. Wood is a lot more work, and it's messy.
If you're buying wood it'll be delivered in a big jumble, which you then have to move and pile. There goes an afternoon.
If you're cutting your own wood there's a lot of manual labour associated with processing a tree. Plus there are additional costs associated with processing the wood on your own. You need to buy wood-processing equipment (chainsaws, saws, axes, wedges, sledgehammers, splitters, etc), then there's the cost of their maintenance and upkeep.
Then, to use the wood, it has to be brought into the house to where your fireplace is located. Moving wood around always leaves a mess. When you put wood down in a pile then pick it up later, some amount of mess is always left behind. Bringing it into the house from the snowy outdoors means tracking snow around and/or having to put boots on and off continuously.
Lots of insects enjoy hibernating in piled wood. When you bring cold wood into the house, inevitably some number of critters will be brought in as well, critters which will then warm up, wake up, and start crawling or buzzing about the house.
But not only is handling wood messy, using a fireplace is messy. Ashes are very light and drift around easily. Moving ashes around, or cleaning your fireplace of ashes, always causes some amount of ash to become airborne allowing it to spread and settle about the house.
Fireplaces are often relatively small and need to be fed regularly. Plus, to get optimal heat from a fire, and optimal efficiency from the wood, dampers need to be adjusted frequently during the burning process.
If you're cutting your own wood there's a lot of manual labour associated with processing a tree. Plus there are additional costs associated with processing the wood on your own. You need to buy wood-processing equipment (chainsaws, saws, axes, wedges, sledgehammers, splitters, etc), then there's the cost of their maintenance and upkeep.
Then, to use the wood, it has to be brought into the house to where your fireplace is located. Moving wood around always leaves a mess. When you put wood down in a pile then pick it up later, some amount of mess is always left behind. Bringing it into the house from the snowy outdoors means tracking snow around and/or having to put boots on and off continuously.
Lots of insects enjoy hibernating in piled wood. When you bring cold wood into the house, inevitably some number of critters will be brought in as well, critters which will then warm up, wake up, and start crawling or buzzing about the house.
But not only is handling wood messy, using a fireplace is messy. Ashes are very light and drift around easily. Moving ashes around, or cleaning your fireplace of ashes, always causes some amount of ash to become airborne allowing it to spread and settle about the house.
Fireplaces are often relatively small and need to be fed regularly. Plus, to get optimal heat from a fire, and optimal efficiency from the wood, dampers need to be adjusted frequently during the burning process.
Depending on your fireplace, lighting a fire can take a bit of skill. If the air in the flue is significantly colder than the air inside the house, when you first light a fire, the smoke will have a tendency to come into the house rather than go up the flue! So if you don't first heat up your flue properly, you can end up smoking yourself out!
Wood can be a really cheap source of fuel, but is it worth the work and the mess? What if there was a way to get the benefits of wood but with a lot less downside?
Outdoor Wood Boilers
In rural areas outdoor wood boilers are becoming more and more popular. An outdoor wood boiler is like a fireplace that is designed to live outside your house. Its job it is to heat up some quantity of liquid to some temperature. An outdoor wood boiler allows you to use wood as a relatively cheap source of fuel, while mitigating many of wood's downsides.
But, like anything, outdoor wood boilers do have their downsides too.
For one, they're more complicated to install. Unless you're handy and will be doing all the work yourself, there's a chance you're going to need to coordinate a bunch of people to get the job done, rather than just working with one person (e.g. your HVAC person). If your experience is anything like ours, you'll have a hard time finding an HVAC person who is willing to take this job on. Sad to say, but for most HVAC people who I've encountered, the answer to every question is "get a gas furnace". So the moment you show them something new, instead of just saying "sorry I don't know anything about outdoor wood boilers" or instead of wanting to learn about something new, they'll say something silly like "that'll never work, you should install a gas furnace".
For one, they're more complicated to install. Unless you're handy and will be doing all the work yourself, there's a chance you're going to need to coordinate a bunch of people to get the job done, rather than just working with one person (e.g. your HVAC person). If your experience is anything like ours, you'll have a hard time finding an HVAC person who is willing to take this job on. Sad to say, but for most HVAC people who I've encountered, the answer to every question is "get a gas furnace". So the moment you show them something new, instead of just saying "sorry I don't know anything about outdoor wood boilers" or instead of wanting to learn about something new, they'll say something silly like "that'll never work, you should install a gas furnace".
Another downside to an outdoor wood boiler (although I consider it rather minor) is that you have to go outside to feed them, and they have to be checked several times each day. I live on a horse farm, so waking up at the same time every day and going outside several times every day, 365.2422 days a year, in every weather condition imaginable, is something I have to do anyway. Adding a pit stop at the wood boiler isn't going to inconvenience me that much, but maybe you feel differently? When it's -20 outside on a Saturday morning, you can't just decide to roll over and sleep-in until noon before bothering to check the boiler, otherwise you'll be getting up to a rather chilly house!
Due to the nature of how they operate, if you're going to have an outdoor wood boiler, it would be a smart idea to have a thermostatically-controlled automatic backup system of some sort. On the one hand it makes sense to have some sort of backup system "just in case". In case you want to go away for a holiday, in case you get stuck at work and can't get home in time, in case you underestimate how much wood you need, in case you underestimate how fast the wood is going to burn, in case you underestimate how cold it's going to get at night, in case you forget to check the boiler before going to bed, in case a storm blows in and shuts down the highway while you're out shopping, in case there's a bad accident on the roads and it takes you longer to get home than anticipated... On the other hand, many jurisdictions, local by-laws, and insurance companies will require you to have a backup system when your primary heat source is from wood. So, in a way, you end up installing two heating systems instead of just one. Therefore some sort of extra expense or additional planning should be anticipated if you want to heat from wood. However, having a backup system does mitigate some of the other downsides such as not being able to sleep-in on Sundays!
On the positive side, wood boilers have a lot going for them. Wood can be a very cheap source of fuel. An outdoor wood boiler can let you use a cheap source of fuel while eliminating or reducing some of the downsides that are associated with using wood.
Wood never needs to be brought inside the house. You can pile your wood once, by your boiler, and never have to move it again except to feed it into the fire. Any mess that is created by having wood piled and handled, stays outside. Any bugs that choose to nest in the wood get thrown directly into the fire without coming (and waking up) inside the house. There's no "moving the wood multiple times", there's no "tracking snow into the house".
A wood boiler, just like any other wood-burning appliance, needs to be cleaned regularly of its ashes. But if you spill a bit of ashes on the ground outside, or some ashes become airborne during the cleaning process outside, so what? Those ashes aren't landing on the floors inside your house, and the airborne ashes aren't settling on any of your indoor furniture.
Compared to an indoor fireplace, outdoor wood boilers are electronically controlled so there's no fiddling with dampers; they do all that themselves automatically. You don't have to open the dampers manually when you add wood, then check and close them off as the fire gets hot in order to maximize the efficiency. A wood boiler's job is to heat a quantity of liquid to a certain temperature. It's intelligent enough on its own to be able to monitor the liquid's temperature and open itself up or closes itself off as required.
Having a large wood chamber means the boiler doesn't need to be filled as often. It still needs to be checked a couple times a day, but it is a lot less frequent than a regular fireplace would require. Compared to an in-house fireplace, an outdoor wood boiler requires a lot less feeding and fiddling.
Outdoor wood boilers are usually lit just once a year, then burn continuously for the season. Therefore there's no "smoking yourself out" every time you light the fire. Besides, by being outside, there's no temperature differential along the flue before lighting your fire, so even if you are re-lighting your boiler frequently there's no downdraft. And even if there was a downdraft, it isn't smoking you out of your house!
The liquid from the outdoor boiler can be used not only to heat your house, but, with the right equipment, can be used to heat up your hot water tanks as well. If your domestic hot water tanks are electric, for example, using your outdoor wood boiler to heat up your domestic hot water will save you on electricity.
The pumps that are used to move the liquid from the boiler to the house don't need to be large. Therefore the electricity cost of running the pumps is small. The boiler itself, although it needs electricity, doesn't need large amounts of electricity, so the on-going costs of operating an outdoor wood boiler are low.
In a power-outage situation, all you need is a small generator to keep a couple small pumps running, and you can still enjoy a completely warm house and all the domestic hot water you want for however long you can keep the generator and pumps going.
Should you ever have any sort of chimney fire or accident with your boiler, it all happens outside and away from your house. Most jurisdictions and insurance companies will mandate a minimum distance away from your house that your wood boiler needs to be installed. By having a decent space between them, you can reduce the risk of a fire destroying your home.
With an outdoor wood boiler all the combustion required to heat your house occurs outside. When a furnace inside your house fires up, unless it specifically takes its oxygen from outside (not all of them do), it will need to take oxygen from inside your house for its combustion. That oxygen needs to be replaced from somewhere. The only way that oxygen can be replaced is to pull it from outside, which brings cold air into your house. Also, unless you have other furnaces that need them, or a fireplace, when you switch to an outdoor wood boiler any chimneys on your house can be capped, leaving fewer ways for cold air and critters to enter your house. If all your combustion occurs outside, then the air inside your house is less susceptible to drying out.
With oil or gas there's always the question of delivery. We have a hilly, gravel, driveway, and our property is located on a country road at the bottom of a hill. Although we do our best to keep our driveway clear of snow and ice, it's always getting snowy and icy in the winter. When does it get icy and snowy? When it's cold. When do we need the most frequent deliveries of oil or gas? When it's cold. So when our driveway is the iciest and snowiest is when we need the delivery person to come the most frequently. When it gets really cold is when they get really busy, meaning it gets harder for them to get around to everyone in time. There have been times when we've had to turn down the thermostat because we weren't sure the oil was going to last until the delivery truck could make it to our place! That's assuming, of course, that they're confident getting to our property at all. After a particularly bad storm, or a nasty bout of freezing rain, our little side road isn't very high on the municipality's list in terms of being a priority for getting ploughed. In short, I'm not fond of relying on someone to drive by with a truck to refill my heating fuel throughout the heating season. I really like the idea of using wood for heat because I have all spring, summer, and fall to gather up my wood, and before the first snow falls I know that I have, on property, all the fuel I need to last the entire winter.
Due to the nature of how they operate, if you're going to have an outdoor wood boiler, it would be a smart idea to have a thermostatically-controlled automatic backup system of some sort. On the one hand it makes sense to have some sort of backup system "just in case". In case you want to go away for a holiday, in case you get stuck at work and can't get home in time, in case you underestimate how much wood you need, in case you underestimate how fast the wood is going to burn, in case you underestimate how cold it's going to get at night, in case you forget to check the boiler before going to bed, in case a storm blows in and shuts down the highway while you're out shopping, in case there's a bad accident on the roads and it takes you longer to get home than anticipated... On the other hand, many jurisdictions, local by-laws, and insurance companies will require you to have a backup system when your primary heat source is from wood. So, in a way, you end up installing two heating systems instead of just one. Therefore some sort of extra expense or additional planning should be anticipated if you want to heat from wood. However, having a backup system does mitigate some of the other downsides such as not being able to sleep-in on Sundays!
On the positive side, wood boilers have a lot going for them. Wood can be a very cheap source of fuel. An outdoor wood boiler can let you use a cheap source of fuel while eliminating or reducing some of the downsides that are associated with using wood.
Wood never needs to be brought inside the house. You can pile your wood once, by your boiler, and never have to move it again except to feed it into the fire. Any mess that is created by having wood piled and handled, stays outside. Any bugs that choose to nest in the wood get thrown directly into the fire without coming (and waking up) inside the house. There's no "moving the wood multiple times", there's no "tracking snow into the house".
A wood boiler, just like any other wood-burning appliance, needs to be cleaned regularly of its ashes. But if you spill a bit of ashes on the ground outside, or some ashes become airborne during the cleaning process outside, so what? Those ashes aren't landing on the floors inside your house, and the airborne ashes aren't settling on any of your indoor furniture.
Compared to an indoor fireplace, outdoor wood boilers are electronically controlled so there's no fiddling with dampers; they do all that themselves automatically. You don't have to open the dampers manually when you add wood, then check and close them off as the fire gets hot in order to maximize the efficiency. A wood boiler's job is to heat a quantity of liquid to a certain temperature. It's intelligent enough on its own to be able to monitor the liquid's temperature and open itself up or closes itself off as required.
Having a large wood chamber means the boiler doesn't need to be filled as often. It still needs to be checked a couple times a day, but it is a lot less frequent than a regular fireplace would require. Compared to an in-house fireplace, an outdoor wood boiler requires a lot less feeding and fiddling.
Outdoor wood boilers are usually lit just once a year, then burn continuously for the season. Therefore there's no "smoking yourself out" every time you light the fire. Besides, by being outside, there's no temperature differential along the flue before lighting your fire, so even if you are re-lighting your boiler frequently there's no downdraft. And even if there was a downdraft, it isn't smoking you out of your house!
The liquid from the outdoor boiler can be used not only to heat your house, but, with the right equipment, can be used to heat up your hot water tanks as well. If your domestic hot water tanks are electric, for example, using your outdoor wood boiler to heat up your domestic hot water will save you on electricity.
The pumps that are used to move the liquid from the boiler to the house don't need to be large. Therefore the electricity cost of running the pumps is small. The boiler itself, although it needs electricity, doesn't need large amounts of electricity, so the on-going costs of operating an outdoor wood boiler are low.
In a power-outage situation, all you need is a small generator to keep a couple small pumps running, and you can still enjoy a completely warm house and all the domestic hot water you want for however long you can keep the generator and pumps going.
Should you ever have any sort of chimney fire or accident with your boiler, it all happens outside and away from your house. Most jurisdictions and insurance companies will mandate a minimum distance away from your house that your wood boiler needs to be installed. By having a decent space between them, you can reduce the risk of a fire destroying your home.
With an outdoor wood boiler all the combustion required to heat your house occurs outside. When a furnace inside your house fires up, unless it specifically takes its oxygen from outside (not all of them do), it will need to take oxygen from inside your house for its combustion. That oxygen needs to be replaced from somewhere. The only way that oxygen can be replaced is to pull it from outside, which brings cold air into your house. Also, unless you have other furnaces that need them, or a fireplace, when you switch to an outdoor wood boiler any chimneys on your house can be capped, leaving fewer ways for cold air and critters to enter your house. If all your combustion occurs outside, then the air inside your house is less susceptible to drying out.
With oil or gas there's always the question of delivery. We have a hilly, gravel, driveway, and our property is located on a country road at the bottom of a hill. Although we do our best to keep our driveway clear of snow and ice, it's always getting snowy and icy in the winter. When does it get icy and snowy? When it's cold. When do we need the most frequent deliveries of oil or gas? When it's cold. So when our driveway is the iciest and snowiest is when we need the delivery person to come the most frequently. When it gets really cold is when they get really busy, meaning it gets harder for them to get around to everyone in time. There have been times when we've had to turn down the thermostat because we weren't sure the oil was going to last until the delivery truck could make it to our place! That's assuming, of course, that they're confident getting to our property at all. After a particularly bad storm, or a nasty bout of freezing rain, our little side road isn't very high on the municipality's list in terms of being a priority for getting ploughed. In short, I'm not fond of relying on someone to drive by with a truck to refill my heating fuel throughout the heating season. I really like the idea of using wood for heat because I have all spring, summer, and fall to gather up my wood, and before the first snow falls I know that I have, on property, all the fuel I need to last the entire winter.
Conclusion
Everyone's situation is different; and for every different situation, a different solution is possible.
In our case electricity would be too expensive and future/on-going costs too uncertain. We didn't want to continue with oil (smelly and potential of spillage), and would have needed to replace our tanks anyway. Since we don't have gas to the door, renting a tank and being locked-in with a vendor means our future costs are unpredictable, so we didn't want to go with a gas furnace. In-ground geothermal is trendy, but even after huge up-front costs there's still larger operational costs and a chance you'd have to supplement with something else for up to a month or two per year. With any of electricity, oil, or gas, their prices fluctuate wildly, and being locked in to any one can be costly.
Outdoor wood boilers don't eliminate the labour involved with using wood but they cut down on the number of times you need to move your wood, and they significantly reduce the mess. Heating from wood can be very cheap, especially if you have your own land from which you can cut and process your own trees (which is true in our case). An outdoor wood boiler allows you to take advantage of a cheap source of fuel and, by living outside, eliminates many of wood's downsides.
In the end we decided to go with an outdoor wood boiler; it's what made the most sense to us.
