House will get "too hot" with a wood stove?

[ericm979]

We're in the process of designing a custom house, working with a design/build firm. The house will be about 2200 sq ft, single floor, and built to Earth Advantage spec for insulation and tightness. It's basically a LEED light that's common in the pacific northwest where the house will be built.

The climate where the house will be has average lows during winter a little below freezing and the record low being around zero. The house will be heated and cooled with mini splits.

The designer/builder has told me that a wood stove would be too hot for the house because it will be so well sealed and insulated. Is that a thing? My plan had been to use a catalytic stove (a Blaze King Sirrocco 30.2 or maybe a smaller 20 series) that can be turned down low. The house won't need a stove to stay warm but firewood has become a hobby and I'd like the option of burning it.

Also right now the best floor plan would put the stove at one end of the house in a large great room and I worry about that part of the house getting too hot. What would you build in to distribute heat to the bedrooms?

 

[all night moe]

You already have the solution.

Blaze King.

If you can incorporate the stove in the center of the house, you would be much better off.

 

[EbS-P]

You need your manual J load calc heating requirements. If it says you only need 12k btus at design temp then yeah the stove will make it too hot. I’d you have 24k heating load at design temp then you get to run the stove some.

Here is the question to ask. What is the average December-February temperature and what is your design temperature. And what is the load calc at that three month average temp.

Your BK choice is right on but to be sure if that wood stove choice you need some data.

 

[EatenByLimestone]

Manual J will tell you if you can run a stove.

 

[DBoon]

Everybody told me the same thing - "the stove will cook you out of your house". My house is 1750 square feet (two stories) and has a heat loss of 18 kBTU at 0 degrees F. I don't run the stove until it gets reliably in the 20s, and when it is warmer I burn silver maple, cherry and walnut. When colder I burn sugar maple, ash and hickory. My firebox is on the small size (Woodstock Keystone) and a catalytic stove helps. I wouldn't go larger than a 2.0 cubic foot firebox or so (i.e., get one of the smaller Blaze Kings).

My house will stay comfortable - not 75 degrees, not 65 degrees, but about 70 degrees, with just the woodstove during the day, and cooler at night (downstairs might reach 65-66 degrees, upstairs cooler). I load twice per day (not pushing the stove hard). The catalytic helps me burn slower and longer. My radiant heat will kick on to level out the temperature around the house, but only runs at about 20% of the capacity it would otherwise have to run at to heat the house full time.

If it approaches zero or goes below, the radiant heat will run more.

Bottom line - know what your heat loss is and then ignore those with nothing but anecdotes and rules of thumb to go by.

 

[ericm979]

We're not far enough into the process to have a Manual J. I ran one on an estimate of the house just to get an idea what the heat loss would be on a well insulated and sealed house that size and that showed that it'd be in the 20kBTU range at the average winter low temp. Of course that's not the real house (and didn't have nearly the amount of windows that will be in the real house). But if that's what it is, I think that's comfortably more than the minimum heat output for the BK stoves.

Isn't the Manual J done at the 98th percentile coldest temp (or something like that)? Ideally I'd be able to run the stove at normal winter temps.

 

[BillBurns]

I would just get one, use it, and shut it down if it gets hot. And crack a window if you need to, lol.

 

[Highbeam]

Look at the epa list for stove output ratings. You will see even the medium sized princess has a low output rating way below 20k btu. Another funny thing is that the smallest bk stoves actually have (or had) a higher minimum heat output rating than the normal sized ones.

The design heat loss of your home is just what needs to be replaced to hold the temperature constant. What often happens to those of us with smaller heating needs is we let the house cool to 68 and then warm the house to 78 during the burn cycle and fire again when the house drops to 68. Your house can absorb a lot of heat.

So the manual j is meaningless at the bottom end. You want a stove that can make at least as much as your house needs.

Or you can do like the Europeans and buy a super tiny cast iron stove and feed it little finger sized pieces of firewood constantly in an effort to micromanage your indoor temperature.

 

[EbS-P]

We're not far enough into the process to have a Manual J. I ran one on an estimate of the house just to get an idea what the heat loss would be on a well insulated and sealed house that size and that showed that it'd be in the 20kBTU range at the average winter low temp. Of course that's not the real house (and didn't have nearly the amount of windows that will be in the real house). But if that's what it is, I think that's comfortably more than the minimum heat output for the BK stoves.

Isn't the Manual J done at the 98th percentile coldest temp (or something like that)? Ideally I'd be able to run the stove at normal winter temps.

Usually 99% but that’s like like 89 hours at or below design temperature a year. On average.

https://www.captiveaire.com/catalogcontent/fans/sup_mpu/doc/winter_summer_design_temps_us.pdf

your HVAC is the most complex system you will have. Get somebody really good. They are rare. Adding a woodstove to a higher preforming stove comes with considerations like it will likely need an oustside fresh air kit. So stove location is crucial to allow that.

 

[ericm979]

Yep I'm planning an OAK. And the house will need HRV and make up air for the cook stove vent hood. The house will need to be balanced so the pressure doesn't go negative and make the wood stove back flow when I open the door to add wood.

 

[begreen]

We're not far enough into the process to have a Manual J. I ran one on an estimate of the house just to get an idea what the heat loss would be on a well insulated and sealed house that size and that showed that it'd be in the 20kBTU range at the average winter low temp. Of course that's not the real house (and didn't have nearly the amount of windows that will be in the real house). But if that's what it is, I think that's comfortably more than the minimum heat output for the BK stoves.

Isn't the Manual J done at the 98th percentile coldest temp (or something like that)? Ideally I'd be able to run the stove at normal winter temps.

More details needed. I would have the designer/builder provide some numbers, otherwise it's just speculation. The house may be 2000 sq ft, but cathedral ceilings will greatly boost the volume of air heated. If there is a lot of large windows, they will also present a major heat loss.

Can you post a sketch of the floorplan marking possible stove locations?

 

[ericm979]

We're in the initial design phase so its too early to post anything.

 

[begreen]

Ok, hard to be specific while in the spitballing phase. What part of CA will this be in?

 

[ericm979]

It's in southern Oregon.

We have a design and should have permits and start work any day. The house is 2350 sq ft, "earth advantage" certified, advanced framing, 6" walls and R30 vaulted ceilings for most rooms. Single story (there's an unheated basement). Lots of big windows for the view. The stove will go on one long side of the 50x18 great room/kitchen. The primary bedroom is the farthest from the stove, down a wide hall and around a corner, so I'm not expecting any heat from the stove to get there. Walls are 9' with the great room vaulted ceiling being higher. Yes there will be ceiling fans. The great room has the most large windows as would be expected so there'll be more heat loss there. HVAC will be mini splits.

I ran loadcalc.net's manual J on the design. Hopefully my results with that are close to the real results. At 40 degrees it'll need 16.5k btus, at 30 22.3k, at 20 28k. Temps rarely go below 20 but historic low is -4. It's below 40 pretty often. It's rare for the high to be under 40 but it does happen some days.

My current stove selection would be a BK 30 series, which per their docs has a low output at 12k btus. Maybe, since I might not want 24 hour fires, the smaller box of the 20 series would be more appropriate? Are there other stoves I should look at?

 

[begreen]

That's a good choice. A mid-sized Kuma could work too. If many of the fires will just be morning or evening chillchasers with the sun warming up the house during the day, then a non-cat could also be a good choice.