Wood-stoves are Space Heaters. Here’s How to Get the Heat into Those Hard to Reach Places.
Many of us enjoy the warm, direct heat of a wood burning stove. At times they over-heat a room and we have to adjust dampers, flues and stove-vents to manage the temperature. But all too often remote bedrooms and bathrooms never seem to get warm enough. If you depend on a single wood-burning stove to heat your whole house you can take some steps to share the heat.
The Hidden Power of Heat
Heat rises. That’s the key to getting heat around and into your whole house. The trick is to take advantage of that thermodynamic to get the heat to go where you need it. Conventional heating systems use a series of ducts to channel heat to other areas. There’s also a fan or fans used to force the air though the ductwork. Wood-burning stoves lack both the ductwork and the fans, but that’s where you can improvise. Here’s where to start.
1. Increase Heat Exchange.
Most wood burning stoves are made out of cast iron. The wood in the firebox burns and makes the iron hot. The hot iron of the stove than raises the temperature of the surrounding air. This is called heat-exchange. You can increase the heat exchanging capability of your stove by placing cast iron objects on top of the stove. They will absorb the heat and increase the area of the stoves hot surface to more air. The more hot surface area exposed to the air, the greater the heat exchange.
Most of these cast iron objects are in the shape of wildlife from iron ducks to cast iron frogs. They’re inexpensive and they work. Every wood burning stove should have one, or two or three….
2. Cast Iron Fans
Cast iron fans take the heat exchange concept to the next level. They are made of cast iron but the have a fan built in. The fan is not powered by electricity. The rising heat from the stove-top causes the fan to slowly turn directing both the heat from the stove and the hot cast iron of the fan into the direction the fan is pointed.
They’re typically used to direct heat towards an opening to another room. They don’t spin rapidly but once they get going they can direct a good amount of warm air beyond the immediate space surrounding the stove.
3. Stove Pipe Heat Traps
Stove pipes vent smoke from a wood-burning stove and get hot even when they’re double insulated with two layers of metal. On their own stove pipes can increase the heat exchange area of a wood-burning stove, but you can increase the amount of heat you draw from the stove pipe with a heat trap.
A stove-pipe heat trap attaches to the stove-pipe above the stove and can be turned to passively direct the heat in a certain direction. They’re not as effective as stovetop fans but they help to maximize the amount of heat exchange from the pipe.
4. Vents in the Ceiling
Upstairs rooms are typically dependent on a stairway to deliver any heat from a wood-burning stove on the first floor. You can create a more direct path for that heat to travel with carefully placed vents in the ceiling. These vents will allow the heat that has risen to the ceiling of a first-floor room to escape through the vent to an upstairs room.
The amount of heat allowed to vent can be controlled like any vent used for a conventional heating system by simply adjusting a baffle in the vent to increase or decrease the air flow. Multiple vents can be placed in the ceiling to increase the amount of heat released into a room or rooms.
The vents should be both in the ceiling and opposite the ceiling vent in the floor above. Make sure you don’t cut through any water pipes or electric wires and drill pilot holes to make sure you are installing the vents between rafters free of obstructions.
You should install a short piece of duct work to connect the floor vent and the ceiling vent to ensure the heat is delivered to the room and not lost in the space between the rafters. This duct doesn’t have to be made out of metal because the heat passing through it is passive. Wood or even thick plastic can be used to create this channel through the rafters.
Drawing heat from the room where the wood-stove is located may require you to sustain a hotter fire, but the more you distribute the heat with stove-top fans and vents the easier it will be to maintain a relatively comfortable temperature in most rooms in the house.
5. Wall Vents
Wall vents are installed high on a wall between the room with the heat source and an adjoining room. They don’t deliver quite as much heat as a vent in the ceiling, but the vents on either side are tilted down or up.
The side with the vent shutters titled down is intended for the room with the heat source. The heat rises up the shutters in the vent and travels across the pipe. Helping the air to draft through the pipe are shutters on the other vent that are titled up. This encourages the air to rise up and out of the pipe and creates the draw of air.
6. Venting Multiple Rooms
You can extend the installation of vents to distribute air across your home to encourage heat-flow. Because the vents have baffles that allow you to close them off, you can manage how much heat is delivered to various rooms depending on time of day and use. As a general rule, the farther the room from the heat source the less the heat but it’s better than no heat.
7. Consider Your Wood Source
Hardwoods burn long and hot. Soft woods burn hotter but faster. It’s often recommended that you get your fire started with softwoods and then add hardwoods to sustain it. This has the added advantage of kick-starting the heat level in your home before the hardwoods take over to keep it warm.
8. Keep it Clean
Have your chimney swept at least once a year. Creosote from smoke builds up and not only can block air flow but catch fire. A chimney fire is very dangerous, burns very hot and can cause the roof to catch fire.
You should also make sure that your stove is well maintained. This includes:
- Cleaning it regularly for creosote buildup.
- Checking the gasket for a clean seat and replacing if necessary.
- Making sure that all stove-pipe joints are sealed and fit properly.
- Cleaning and maintaining any flues or other moving parts that control air-flow into or out of the stove.
9. Stove Size
Regardless of how ambitious you get with heat-sharing ideas, a small wood-stove can only do so much. If you want to heat your whole house with one wood-burning stove, make sure you ask your installer or retailer about BTU’s and the amount of living space you plan to heat.
It would also be a good idea to do some homework if you’re installing a new stove for the first time or planning to replace one. If you’re current stove is too small and you don’t want to replace it with a larger one or the living space is just too large to heat, you could consider a second stove.
10. A Second Stove?
If all else fails you may have to think about installing a second stove somewhere in your house to allow your heat to meet in the middle. This could be a second-story stove or another stove at the opposite end of the house. It doesn’t have to be as big as your primary stove but should use the same fuel. If you’ve decided that a pellet stove is your heat source of choice it doesn’t make a lot of sense to have a second stove requiring firewood.
You should also make sure that any second stove is checked regularly. Leaving any wood-burning stove unattended can be dangerous. A pellet stove is safer and can be unattended for a period of time, but the open fire of a wood-burning stove can create problems if there are any openings like air-vents allowing for the potential escape of hot coals or smoke.
You also have to balance the cost of purchasing and installing a second wood-stove plus the added costs for firewood or pellets. If whole-house heating with one wood stove is a chronic challenge on particularly frigid days, a second stove may be your best choice unless you turn to a different alternative heat source like electric baseboard heating or an electric space heater. A vented propane heater connected to a propane tank used for outdoor grills is another option for short-term heat.
Putting it All Together
On their own, each one of these heat sharing ideas is only so effective. The good news is that most of them are relatively inexpensive for the benefits they provide even though they are passive systems. However, if you combine these ideas you may be surprised to see that even a single wood-fired heating source can keep your whole house warm.