Indoor boilers

Dmurph2016

New Member
May 9, 2019
30
Mass
Has anyone replaced a oil boiler with a indoor wood burning one ? If the concept is the same as the outdoor ones, the burn times should be pretty long? A family member is in need soon to replace their oil fires boiler and was looking into this, I’d like to get some feedback so I can better help them make a decision. Thanks

edit. They have forced hot water not forced hot air
 

Highbeam

Minister of Fire
Dec 28, 2006
17,195
Mt. Rainier Foothills, WA
Has anyone replaced a oil boiler with a indoor wood burning one ? If the concept is the same as the outdoor ones, the burn times should be pretty long? A family member is in need soon to replace their oil fires boiler and was looking into this, I’d like to get some feedback so I can better help them make a decision. Thanks

edit. They have forced hot water not forced hot air
Replace the oil boiler with another automatic non wood boiler. Then consider how you would add a wood boiler as well. Very few people are "cut out" to heat 100% with wood and insurance companies want automatic heat.

Indoor wood boiler systems will cost 15k plus by the time you're done.
 

peakbagger

Minister of Fire
Jul 11, 2008
5,257
Northern NH
Many members have wood boilers in the basement that is their primary heating source with some sort of backup. If the family member has a mortgage they technically need to have another source of heat like natural gas or heating oil. Some banks are now allowing pellet boilers to be primary heating source as long as they have bulk deliveries.

The problem for just putting a wood boiler in place of an oil/gas boiler is that a wood boiler needs to burn at high rate preferably flat out to be most efficient. If you pay more you can get more advanced controls and designs that will allow the boiler to be turned down somewhat and still be efficient. Other designs just shut the air off to the boiler to get it to reduce its output but that means low efficiency and creosote. If the owner wants to spend their time sitting next to the boiler they can vary the fuel load but its definitely not an automatic operation. The way 95% of the indoor wood boilers do it is install a large tank of water that can be heated up from the wood boiler. The heat in the tank then is distributed to the house while the wood boiler if off line. Depending on heating demand of the house and the tank volume, the storage tank may last a couple of days prior to having to fire the boiler off but most folks burn once a day.

Depending on the equipment selected and tank size a rough guess is 10K or more if they go with higher end gasifier boilers with advanced controls. The payback is very dependent on where they get their wood, how well its seasoned and what they pay for the wood. In many cases its a very long payback unless they have access to free wood and are willing to put the time in to cutting, splitting and seasoning wood for 2 years. Its major commitment. If they have natural gas they may be better off buying a new condensing type boiler, improving their domestic hot water system and putting in more advanced controls like outdoor reset.

A wood boiler and storage also takes up a lot of space and getting the storage tank in the house (usually 500 to 1000 gallons) is difficult in many homes.

Another option is wood pellet boilers,they are a lot more automatic and in some areas of Mass there are bulk deliveries. Bulk deliveries cut out the handling of bags of pellets but the storage bins take up a lot of space.

Mass utilities usually have deals on energy audits and many will pay a portion of the cost to put in place the recommendations to reduce energy usage. On an older home the annual energy usage can drop 10 to 25%. If the home has a good location for solar, Mass has very generous incentives. Solar with net metering and a couple of minisplits is a bigger initial investment but potentially a shorter payback. A minisplit heats and cools so if they have AC, the minisplits are for more efficient than most central systems and definitely more than window units.
 
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Drewby

New Member
Aug 20, 2018
38
LaCrosse wi
I heat with wood in an indoor boiler. In the Midwest propane is so cheap that wood can never pay for itself at these prices. Even if you cut all of it for free because you like doing it as a hobby you cannot pencil out the new boiler in the long run. If you get an awesome deal on a used boiler and do the install very cheap it will start to look better for wood. But you still have to like the work of it. Now when propane is $3.00 per gallon its a different story.
There is some people on this forum that have $15k-$20k systems and love them. I assume that their fuel prices are pretty high to justify those high upfront costs.
 

maple1

Minister of Fire
Sep 15, 2011
10,438
Nova Scotia
Has anyone replaced a oil boiler with a indoor wood burning one ? If the concept is the same as the outdoor ones, the burn times should be pretty long? A family member is in need soon to replace their oil fires boiler and was looking into this, I’d like to get some feedback so I can better help them make a decision. Thanks

edit. They have forced hot water not forced hot air
They should not put themselves in a situation where wood is their only source of heat. I suspect their insurance people would highly object also. If anything, perhaps replace the oil boiler with a new more efficient cold start one, and find a way to add a wood fired something as a second heat source.

Long burn times are detrimental to wood boiler operation. Those come at the expense of reduced efficiency, & creosote generating smoldering.