Advice: High ceilings + how much of my home's sq ft can I feasibly heat?

[Magicshanoo]

Hello. I have a new modern, south-facing home being built in S.E. TN on a slab. It has passive solar design with windows on the south face and a roof overhang that lets winter sun into the home. It is a shed style roof that reaches 16 feet at its highest. The stove I'd like to put in will top vent through the roof at about 12-13 feet. I understand heating square footage when the space is generally open, but after searching, I still have difficulty understanding the amount of heat I can expect to share with less open spaces. Furthermore, should I take into account my ceiling height in picking a stove size?

The main level is 1800 sqft. There is an upstairs, but it has its own heat source.

We will have central heat, but I'd instead love to run wood all winter if it were comfortable. I plan on installing a large ceiling fan in the living room with very low speed capable of moving more air and, if it would help, also running our hvac fan. Is it wiser to get a small stove for the living room, close the bedrooms and buy space heaters or would you buy one for the entire 1800 ft^2?

Could I heat the entire level without overheating the living room? My family works and schools at home, generally spending our time together in the main spaces, so the comfort there is most important.

Basically, what square footage would you use to determine which stove fits my particular needs?

I attached the floorplan which includes the proposed location of the stove. Also, if any guidance on brands and models occurs to you, I'd love to hear the suggestions.

Many thank you's in advance.

 

[Lake Girl]

Patience on waiting for replys ... the wood stove experts will be along to give you ideas. Stove position in the LR seems to be optimal for moving heat and the hvac fan will promote air movement.

Good luck!

 

[EatenByLimestone]

The size of the wood stove you choose depends on many variables, as your research has hinted at. Pure square footage indicated by the manufacturer isn't always a good indication of the ability of the stove. Houses have different orientations, insulation, and yours was designed for passive heating. That's the big wildcard in my view. How much will that contribute to your heating requirements? I think I would look into a medium sized stove. Have you decided on catalytic technology or secondary burn tubes?

 

[Ashful]

This will not be an issue. I'd put a pair of ceiling fans on drop poles in the living/dining area to circulate air. Your house is laid out almost identically to half of my first floor, and we have 14' ceilings in our similar (16' X 32') living/dining space, with rooms off both sides.

We also get a lot of solar heating in our living room. Makes it often too hot during the day, with the stove going in there, so expect to deal with some of that, unless you like it warm. "Too hot" for us is anything over 75F, we normally aim for 70 - 73F.

One note, the bedrooms will be cool, in this layout. Many folks prefer that, but zoning off the heat in this rooms would be a huge advantage, here.


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[St. Coemgen]

Furthermore, should I take into account my ceiling height in picking a stove size?

Yes. Absolutely.

The concept of sq ft in a North American standard and assumes a standard ceiling height and wall insulation. Which is often not only unrealistic but out right wrong.

In Europe they rate stoves by the volume to heat, which makes much more sense. Many wood stove manufactures have a European web site, so just go to one of those to get a handle of the stove size you need to heat your real world volume.

We will have central heat, but I'd instead love to run wood all winter if it were comfortable. I plan on installing a large ceiling fan in the living room with very low speed capable of moving more air and, if it would help, also running our hvac fan.

A ceiling fan will not move much heat. We have one. So I know. You need some type of forced air fan that directs air to the other rooms. These are rather cheap to buy and install. But still may not provide the heat needed.

For more information, see:

http://woodheat.org/moving-heat-around-the-house.html

Could I heat the entire level without overheating the living room? My family works and schools at home, generally spending our time together in the main spaces, so the comfort there is most important.

Depends on the stove. Many cast iron stoves work on the principle of radiant heat, so can overheat the local environment. Other stoves that work on the concept of convective heating are less likely to overheat the local room.

Basically, what square footage would you use to determine which stove fits my particular needs?

Again, you need to think in volumes, not two dimensional measures like sq ft. But given your floor plan, I would say it would difficult to heat with just one stove given the many rooms to heat. Heating with a single stove is best with an open floor plan, which you do not have.

For example, to help with internal heating using one of our 8 KW stoves, we removed two walls in our house. We still need a secondary 6 KW stove for the back room simply due to the fact the heat does not move through door ways enough, despite forced air movement using fans.

 

[Ashful]

A ceiling fan will not move much heat. We have one. So I know.

Fans don't move heat, they move air, whether that air be hot or cold.

I have two ceiling fans in the room with the stove shown in my avatar, which has some similarity to the OP's living/dining room. The room is 16' wide x 32' long, with 14' ceiling, and the stove is at one end. We have the fan over the stove pulling up, and the one at the farther end of the room pushing down, both on drop poles putting them maybe 10' above the floor. It's usually warmer at the end of the room farthest from the stove than it is at the end of the room closer to the stove (except right in front of stove, of course), with these fans running, so they do indeed move hot air pretty well.

If you want to go into cold air vs. hot air density symantics, remember the cold air you're moving is just displacing hot air, potato / potatoe. It's all about getting the right direction of flow in the right place, but making a blanket statement that fans don't move hot air is just plain stupid.

 

[rawlins02]

Consider using a fan to generate a convective flow of air out of the room. For example, if you were to place a floor box fan in the kitchen, forcing cooler air into the living room, warm air will flow out of the living room and down the hallway toward the bedrooms. As others have mentioned, a fan will be more efficient moving cooler air into the room. That cooler air will displace warmer air, forcing it out of the living room.

 

[ElmBurner]

If you are designed as a passive solar house, you should have good insulation, so the temperatures will naturally tend to normalize across the house. No room should be drafty/cool unless you are exposed to a lot of wind and even then, it shouldn't be bad.

My house was built three years ago and I program the HVAC fan to run in "circulate" mode (20 minutes out of every hour, the fan is on). This is enough to get all the rooms in the house within 2-3 degrees of the room where I have the stove in even the coldest weather. If I up that to run 100% of the time, the temperature is basically identical, anywhere you go.

Obviously this requires good system design and tuning, such that you have enough properly placed cold air returns and vents and that the vents are balanced to change the air in the room 2-4 times / hour.

My problem is that my stove isn't big enough to heat the volume of my house for the burn times that are convenient for me. On weekends, when I can feed it every 6 hours or so, the house is perfect. During the week, when I load it around 6:30 a.m. then again at 6 pm, the house has cooled 4-5 degrees and I have to ramp it back up.

You may find that a moderate to large sized catalytic stove with a long burn time is going to be what is needed. It might be able to heat your second level, as well, but it looks like you have two completely separate HVAC systems, so the only way you would get any heat to the second floor is up the stairwell. This is obviously not ideal.

 

[HappyCamperMan]

If you are designed as a passive solar house, you should have good insulation, so the temperatures will naturally tend to normalize across the house. No room should be drafty/cool unless you are exposed to a lot of wind and even then, it shouldn't be bad.

My house was built three years ago and I program the HVAC fan to run in "circulate" mode (20 minutes out of every hour, the fan is on). This is enough to get all the rooms in the house within 2-3 degrees of the room where I have the stove in even the coldest weather. If I up that to run 100% of the time, the temperature is basically identical, anywhere you go.

Obviously this requires good system design and tuning, such that you have enough properly placed cold air returns and vents and that the vents are balanced to change the air in the room 2-4 times / hour.

My problem is that my stove isn't big enough to heat the volume of my house for the burn times that are convenient for me. On weekends, when I can feed it every 6 hours or so, the house is perfect. During the week, when I load it around 6:30 a.m. then again at 6 pm, the house has cooled 4-5 degrees and I have to ramp it back up.

You may find that a moderate to large sized catalytic stove with a long burn time is going to be what is needed. It might be able to heat your second level, as well, but it looks like you have two completely separate HVAC systems, so the only way you would get any heat to the second floor is up the stairwell. This is obviously not ideal.

 

[HappyCamperMan]

Hi, ElmBurner...

May I ask what type of programmable thermostat you are using?

 

[ElmBurner]

Hi, ElmBurner...

May I ask what type of programmable thermostat you are using?

It's a Honeywell unit that came with the HVAC system we installed.

The nearest equivalent now would be the Prestige IAQ, but mine doesn't have WiFi or the other internet-connected stuff.

You can buy DIY'er thermostats with a circulate function, though.

 

[Ashful]

I've never been able to find a function on my Honeywell RTH7500D's that will cycle the fan on a time schedule, so model number would be very handy. I've also been hunting for such a feature.

 

[ElmBurner]

I've never been able to find a function on my Honeywell RTH7500D's that will cycle the fan on a time schedule, so model number would be very handy. I've also been hunting for such a feature.

The Vision Pro 8000 has it. Price is around $130.

It really depends on what you need the thermostat to do, though. It might be best to call your HVAC dealer or Honeywell (or another thermostat manufacturer) and explain your situation.

 

[Ashful]

I just need it to cycle a few minutes out of each hour, to resolve stratification in my three floors of AC on one zone, on days when it's not hot enough to force the system to cycle frequently. Third floor gets hot, second floor where t'stat is located stays cool, system doesn't run.