Wood burning fireplace for heat

[Chapap]

Down here in Florida most fireplaces are decorative. My parents use theirs for the fun of it and for heat. It seems like it could heat the entire house, but it's inefficient at getting the heat into the house. It's got a nice insert thing... like an iron box with heavy doors and built in blower. The box gets quite hot, but it just doesn't transfer the heat to the air. It can heat the house, but they have to pack it full, open the dampers, and really get it hot. Seems like one serving of wood should go allot farther than it does. Any tips on servicing it?

Also I'm house shopping and would like a fireplace. Any tips on good inserts? I imagine to really get heat out of it, it'd need to be attached to a good size radiator.

 

[Roert42]

sounds like the blower may not be working properly.

A typical open fireplace you see in the movies is about 25/30% efficient, most of the heat goes up the chimney. You need a big fire to get much from it, and the larger the fire the larger the draft required to feed it, so the other rooms in the house will get colder as the room with the fire gest warmer.

A decent insert or wood stove should be at least 70% efficient. An insert will need a blower to pull the hot air from around the fire box and blow it into the room.

I've seen the blowers on a fireplace installed wrong. I would get a manual/ installation instructions for yours and look and see how it's supposed to be setup. I think most fans are designed to suck in the air from the room, and push the hot air out from around the fire box out a vent.

 

[2011Supercab]

The type of wood has a lot to do with it also.

The Best Firewood: Heat Values and Wood-Burning Tips

Here is a list of the best firewoods for your woodstove and fireplace based on its heat value and more tips for burning firewood in the winter from The Old Farmer's Almanac.

www.almanac.com

 

[Josh B]

The best setup I've seen with a fireplace was with a wood stove included.
It's been a long time since I saw it so the memory is vague, but I believe it had a raised fireplace, probable not a foot above the floor, and a stove from United States Stove Co in Tennessee, I remember the brand so well because I have one here, although mine will burn wood or coal.
Either way, they both have a fan that blows the warm air around the fire chamber and out the bottom front, into the house
He had an installer set it up, this is about a 250 pound stove, but in my book the best stoves you can buy.

 

[RonD]

Inserts should generate quite a bit of heat, especially if they have an electric motor to pull air in at the bottom and push it out at the top
Non-powered inserts work as well, "hot air rises", so as the insert is heated up a natural flow starts, pulls in cooler air from lower vents and pushes out warmer air from upper vents

Draw back of open fireplace(and wood stoves) is that it pulls in already heated from inside the house and sends it up the chimney, and that pulls in colder outside air from unsealed doors and windows
You can add a fresh air vent so the wood fire is using outside air, not heated house air, to stay burning

 

[CrabGuy]

My son uses only a small airtight wood stove in winter; his propane FAU is just too expensive to run. To get warm air to other rooms he uses the 'fan only' function on the thermostat. It actually works pretty well to distribute heat since the return intake is 5' away in the ceiling. He needs to figure out how to make the fan cycle on and off though so it doesn't run all the time. Doing tree work he has a near endless supply of black oak, madrone, and cedar that he can feed to his splitter and sells the excess.

 

[franklin2]

When I moved into this house it had a insert. I tried it, didn't like it. Like you I found out it didn't heat very well, and to get any heat at all you have to run the blower. That's a negative for me, since before fuel got so high, the main use for a wood stove is when the power is out. If the insert will not heat the house without the blower on, it's no good to me. The instructions with the insert even say do not fire it without using the blower, or it can overheat and ruin the blower system. And besides that, the blower is very noisy.

Another thing to be aware of, a lot of these inserts are called "slammers". They are called that because people take the insert and just slide it into the fireplace and call it good. It's not good and can cause chimney fires. The insert needs to be plumbed properly into the liner of the chimney. It's very prone to cooling and cresote buildup around the insert if it's not plumbed into the chimney liner.

I sold mine. I then went to my local steel supplier and they sheared a large piece of 3/16 steel for me to cover the entire hole in the fireplace. I torched a round hole in it for the stove pipe, and piped in a pipe and tee into the stainless chimney liner, and ran the pipe through the hole I torched. I then mounted the whole thing to the front of the fireplace. I then bought a woodstove fire resistant pad and sat my woodstove out from the fireplace in the room.

Much Much better, and no blower required. Of course it takes up some room sitting out there but since fuel went up I am using it for my primary heat source. It works well.

 

[Chapap]

I have no idea how it’s installed, but it’s had two decades of fires in it so I guess they did it right. The fan does work and it heats very well, but the box has to get scalding hot for it to put out significantly hot air. It doesn’t use outside air for combustion, but it has adjustable lovers at the bottom. We have them adjusted all the way closed so one load of wood lasts all night. We can pack it full and there’ll only be a couple smoldering sticks in the morning.

Here’s a pic. Anyone have any idea what it is?

 

[2011Supercab]

We have them adjusted all the way closed so one load of wood lasts all night. We can pack it full and there’ll only be a couple smoldering sticks in the morning.

And that is why you don't get much heat out of it.

Wide open is hot/fire and short lasting

Fully closed is smoldering/embers and long lasting

You have to find a happy medium and add wood sometime during the night if you want good heat.

 

[Chapap]

And that is why you don't get much heat out of it.

Wide open is hot/fire and short lasting

Fully closed is smoldering/embers and long lasting

It just seems like smoldering should do better than it does. The box is too hot to touch but the air blowing out is mildly warm. I guess I could do a temp test of the box with fan on and off. I imagine it’s a cheap one so not much engineering for efficiency. A bunch of heat sink panels in the casting is what I’d like to see.

 

[Cees Klumper]

We have both types in our house: insert with blower, and a separate stove that sits in the room, piped back into the chimney, no blower. The latter is far more effective at heating and we rarely run the insert for that reason.

 

[Chapap]

We have both types in our house: insert with blower, and a separate stove that sits in the room, piped back into the chimney, no blower. The latter is far more effective at heating and we rarely run the insert for that reason.

Seems like the stove things rely more on radiant heat. Maybe that's how they're designed. A blower ought to be pretty good at capturing convective heat, but there's just no surface area on these things.

 

[franklin2]

Seems like the stove things rely more on radiant heat. Maybe that's how they're designed. A blower ought to be pretty good at capturing convective heat, but there's just no surface area on these things.

I believe after this season it's time for you to check on things. Pull the insert out and see how much cresote build-up you have and get the chimney checked/cleaned. Putt putting all night with the dampers almost shut is not good. If you find a lot of black sticky stuff in the chimney that stuff burns like gasoline if it gets lit off. Being in Florida where it doesn't get that cold aggravates the whole thing.

If you have never checked on it, be careful with it and don't let it get too hot till you see how much build-up you have. I hope you have some sort of liner in your chimney. What happens, over time as the chimney gets older some of the mortar falls out and leaves gaps. That sticky black oily stuff (cresote) can leak out through these cracks into the house, in the attic if the chimney goes through the attic. Then one good hot over fire of the system and that stuff lights off and burns the house down. A liner helps keep things inside the chimney.

 

[bilbo]

My in-laws heated with wood for a long time. When I first met my wife they had a wood stove. The stove room was like a sauna to make the rest of the house comfortable. Then they upgraded to an outdoor wood-fired boiler that used an air handler and heat exchangers. To increase efficiency you have to lower the flue gas temp. As franklin2 mentioned you have to be careful as of it gets too low things start condensing out in the flue and you have fires. Every once in a while the flue on that outdoor boiler would take off and it looked and sounded like a jet engine pointed straight up in the air. No big deal as it was a quarter mile from the house but probably wouldn’t be good inside a house. Hot fires keep this at bay. Their final upgrade was a gas furnace. The wood boiler sits unused. Wood heat sounds great until you have to deal with it. They had a sawmill nearby and used scalpings, so the fuel was "free" but still required a lot of work to go pick up, haul, unload, cut/prep, store, etc.. And it wasn't great firewood. Their other source was clearing out shelter belts. The saying that heating with wood warms you twice is true for sure. If they had to buy wood, it wasn't any cheaper than propane.

I would say just use it for the ambience and "romantic" factor. There's no way I would rely on a stove or especially fireplace for the bulk of my home heating, even here in FL. Or there are gas fireplace inserts too. Not the same I know but extremely convenient!

 

[rumblecloud]

This is what we have now for a secondary heat source.



It was an insert (Heatilator brand) with a blower. But as has been said, most of the heat went up the chimney. While the newer set up is more efficient and heats the room, the rest of the house gets cold because the thermostat is in the same room as the stove.

The insert your parents have is very similar to one my my sister-in-law has. She's up in the UP near Saulte Saint Marie. Similar issue with the heat not getting to the other parts of the house. Fans help. Kept at lower speeds to gently move the air around works pretty good, but not ideal.

EDIT: Plus one on the creosote build-up. We clean ours every year and there is still quite a bit of soot build-up.