BK Ashford 30 in unfinished basement

[NewToVT]

I’ve searched this forum and I’ve seen some related threads but not quite what I’m looking for.

I just placed an order for a BK Ashford 30 through a local dealer, and then the next day I came across this sentence in the BK Ashford manual, and now I’m questioning the order:

“All Blaze King wood burning appliances are designed as radiant room space heaters. They have been tested and certified to be installed in insulated, habitable rooms within your dwelling. The appliance has not been designed to be installed in a concrete, uninsulated basement or in a shop/garage environment. Such applications may cause the thermostat to be unresponsive due the constant call for heat resulting in appliance being in a constant over fire situation. Consequential damage from this type of operation will deem the warranty null and void.”

I did a lot research and reading on this forum and elsewhere before deciding on the Ashford. I chose a BK because it seemed to have the fewest complaints, and because of the thermostat function, which seemed to lower the risk of overfiring. However, our basement has concrete walls and floors and is unfinished, and uninsulated except for the sill (that has fiberglass insulation), so now I’m concerned about the decision, mainly the overfiring concern, as that was exactly what I was trying to avoid by going with the BK.

The stove would NOT be our primary heat source for the main level. It would be the primary for the basement.

The basement currently has no heat source, so the wood stove would be the primary heat source for the basement, but it needs to be comfortable down there since we use it as a guest space (not Airbnb, just friends/family) and workout space, so ideally not much more than 70 F near the floor.

So far the coldest our basement has been with no heat at all is 54 F, even when temperatures dropped into the negatives (F) overnight.

We would not use the stove in the shoulder seasons as the basement stays relatively warm until outside temps start dropping into the 30s or lower during the day. This would be winter use only.

We have an on demand propane boiler/baseboard heat system for the main level.
We also have a heat pump rated down to -5 F

It would be nice if the stove can warm our floors on the main level and provide some heat to the main level, to reduce the need for as much propane heat ($$$$) when temps get too cold for the heat pump to work efficiently. We typically keep our thermostat on the main level at about 66 F. We really hate when it’s too hot, we’re not looking to wear shorts and t-shirts inside in the winter. We moved to Vermont because we like it cold.

Here are the specifics, including specs above and I’ve attached a few pictures

-We live in Central Vermont
-Our house was built in 2009
-the house is 1400 sqft, all one level, mostly open layout with 2 small bedrooms, 7.5 ft ceilings
-the basement is also 1400 sqft, a set of stairs leads up from the basement into the breeze room.
-the basement has concrete walls and floors and is unfinished and uninsulated except for the sill (fiberglass insulation).
-the ceilings in the basement are 10 ft
-The flue is in the center of the house and has an 8” diameter (the dealer will install the new stove and put in a 6” reducer to the stove)
-We think the flue height is somewhere around 22 - 25 ft: I don’t have an exact measure but it runs from the basement up through the main level and the roof
-There is an old stove in the basement that will be removed when the new one is installed. A chimney sweep inspected the stove and chimney when we bought the house (8 months ago) and he said the chimney looks great but the current stove is not safe to use, so we don’t use it)
- main level has baseboard heat (propane on-demand boiler) and a heat pump (rated to -5 F)
-the basement is currently unheated

So to wrap up, my questions are:
1-Is overfiring a concern given our setup, will we have issues with the thermostat on the BK Ashford, and if so is there any way to manage this?
2-Are we likely to have issues with the 8” flue with 6” reducer?
3-Is the Ashford 30 likely to meet our needs to heat the basement without overheating and provide some heat to our main level that we can then supplement with baseboard heat or heat pump.

Please note, to keep this specific, were not looking for recommendations on other stoves at this time, right now we just want to figure out if we made a mistake with this order and should try to cancel.

We appreciate your help and feedback. Thank you!

 

[all night moe]

It would not take much to insulate those walls.
2'' foamboard is all that's needed then, run that Ashford.... low n slow.
Once heated, that 8'' flue will probably overdraft. When cold, draft may be a bit difficult to establish.

I'd put the reducer right at the support box. Run 6'' double wall straight out off stove. No cleanout-T.
If you find over drafting an issue, install a key damper 18'' up from stove.

 

[kborndale]

Insulate the basement, any stove has a tough time heating and uninsulated basement as much of the heat goes to heat up the walls and earth. Insulation will save you a lot of wood. Put some carpet tiles on the floor and foam on the walls. You will not regret it.

 

[stoveliker]

Built in 2009 in VT and no external insulation...?!

I don't know if it'll overfire. I do think it's important to insulate the basement; you'll loose 30% of the BTUs to the outside otherwise. I.e. 30% of effort or $$ for the wood is lost. (Also, fiberglass in front of the rim joist sucks,. especially when you heat the basement; air flow can go through fiberglass, leading to warm moist air reaching a piece of 1.5" thick wood outside of which it's winter cold. Condensation and mold/rot will ensue.)

An 8" flue is not great; at the transition the gases will slow down and cool more. Running these stoves low you already have very low flue gas temps, and this risks creosote accumulation.
Is the ID 8" or the OD? (6" class A often has an 8" OD.)

 

[NewToVT]

It would not take much to insulate those walls.
2'' foamboard is all that's needed then, run that Ashford.... low n slow.
Once heated, that 8'' flue will probably overdraft. When cold, draft may be a bit difficult to establish.

I'd put the reducer right at the support box. Run 6'' double wall straight out off stove. No cleanout-T.
If you find over drafting an issue, install a key damper 18'' up from stove.

Thanks, the problem with foamboard is that it seems we would then need to drywall over it for fire safety, and that’s basically finishing the basement, which is not something we planned to do, but maybe we need to look into it.

Alternatively we might need to rethink putting a stove down there at all if we can still cancel the order.

Thanks for the suggestions on the flue.

 

[NewToVT]

Insulate the basement, any stove has a tough time heating and uninsulated basement as much of the heat goes to heat up the walls and earth. Insulation will save you a lot of wood. Put some carpet tiles on the floor and foam on the walls. You will not regret i

Built in 2009 in VT and no external insulation...?!

I don't know if it'll overfire. I do think it's important to insulate the basement; you'll loose 30% of the BTUs to the outside otherwise. I.e. 30% of effort or $$ for the wood is lost. (Also, fiberglass in front of the rim joist sucks,. especially when you heat the basement; air flow can go through fiberglass, leading to warm moist air reaching a piece of 1.5" thick wood outside of which it's winter cold. Condensation and mold/rot will ensue.)

An 8" flue is not great; at the transition the gases will slow down and cool more. Running these stoves low you already have very low flue gas temps, and this risks creosote accumulation.
Is the ID 8" or the OD? (6" class A often has an 8" OD.)

I don’t know if the exterior walls of the basement are insulated, I’ll see what I can find out. We know who the builder is so we can get in touch. Moisture wise it seems to be pretty well sealed, but I don’t know what they did in terms of insulation.

Thanks for the heads up on the rim joist. We were thinking about having the rim joist spray foamed at some point, so we’d make it a higher priority if we go ahead with the stove.

I have no previous experience with wood stoves or flues (probably pretty obvious at this point). I measured the diameter of the flue exterior in the basement and it’s 8 inches, so I guess it could be 6” ID, which would solve one part of the problem.

 

[NewToVT]

Insulate the basement, any stove has a tough time heating and uninsulated basement as much of the heat goes to heat up the walls and earth. Insulation will save you a lot of wood. Put some carpet tiles on the floor and foam on the walls. You will not regret it.

Thanks, I have the same comment/question I had for all night moe: can you put up foam board without drywalling over? It seems like that could be a fire risk.

 

[kborndale]

Most important thing is get your wood yesterday so it's dry by next winter.

 

[kborndale]

Thanks, I have the same comment/question I had for all night moe: can you put up foam board without drywalling over? It seems like that could be a fire risk.

They may make a non combustible foam board you could put near the stove, I'm not sure. Regardless, you could put regular foam board around the entire basement except for within 36" of the stove.

 

[all night moe]

Your stove is in the middle of the basement. The joists and subfloor above would catch on fire 1st.
The only reason for sheetrock would be for aesthetics so, you may want that anyway. You could hook the stove up now, and insulate as you go. Drywall later.....

Whatever your budget approves.
Don't cancel your order. It's a great stove. You most likely have a 6'' flue. Measure the inside dia.

 

[NewToVT]

Your stove is in the middle of the basement. The joists and subfloor above would catch on fire 1st.
The only reason for sheetrock would be for aesthetics so, you may want that anyway. You could hook the stove up now, and insulate as you go. Drywall later.....

Whatever your budget approves.
Don't cancel your order. It's a great stove. You most likely have a 6'' flue. Measure the inside dia.

Makes sense, thanks!
We’ll have to figure out the insulation, but if we don’t need to drywall it should be more feasible.

 

[stoveliker]

No, polystyrene foam board does need to be covered by drywall (or rockwool) everywhere per firecode.

Regarding external insulation, if there is a vapor barrier there (e.g. closed cell foam board) you don't want a vapor barrier inside in the rim joist (as spray foam would be) because any moisture from the concrete that wicks through the sil plate will have no way to dry out, leading to rotting rim joists.

Before doing something there do talk to a knowledgeable person - noting that many (insulation) contractors are not very knowledgeable.

Regarding the stove, you can still put a stove in without a thermostat. It's the thermostat combined with an uninsulated space that is potentially problematic. A stove without thermostat would work normally.
Problem is that you would have to size it to work with the uninsulated BTU need which would be too much if you end up insulating it later.

6" is good as it works with many stoves.

 

[bigealta]

I wonder why that existing Vermont castings defiant (i believe) was determined to be "unsafe".
I would definitely have a woodstove down there in that spot.

 

[all night moe]

I wonder why that existing Vermont castings defiant (i believe) was determined to be "unsafe".
I would definitely have a woodstove down there in that spot.

I was wondering the same. Possibly just needs new gasketing/cementing? Or, warped panels inside from over firing?

Care to share some more pics OP?

 

[BKVP]

Let me add in here:
When someone installs a wood heater in the uninsulated basement, they SOMETIMES complain it won't put out enough heat. These situations don't match expectations of heating FROM the basement.

SOME users are tempted to run the stove other than as directed. Such transgressions include, leaving front loading door cracked open, running stove with bypass open, removing main air tube lid and placing an item to keep thermostat blade open continuously.

This is the reason for the statement in the manuals.

I agree with others, insulate basement walls this year (check for tax credits) and next year run a wood stove. This will also permit sufficient time to build wood shed and fill it.

BKVP

 

[stoveliker]

Interesting, as the text quoted by the OP explicitly mentions thermostat issues (which is different from user misbehavior upon not being satisfied, as you allude too).

 

[BKVP]

When you leave the door open, bypass open, the thermostat doesn't know this, so as the stove gets over heated, the blade closes and no matter the adjustment to the knob, the thermostat does not respond. Close the door and bypass, it will function as designed and intended.

BKVP

 

[stoveliker]

If that is the true and only reason for the advice against installation in uninsulated basements, the manual needs to be revised as it contains needless and wrong statements:

"The appliance has not been designed to be installed in a concrete, uninsulated basement or in a shop/garage environment. Such applications may cause the thermostat to be unresponsive due the constant call for heat resulting in appliance being in a constant over fire situation. "

 

[BKVP]

It is true, I wouldn't post otherwise.

What it should say is "If your expectations are.....keep in mind concrete, unisulated basements present a challenge....and you should not deviate from these instructions in an effort to....Doing so can damage your stove and not be supported by warranty.

BKVP

 

[stoveliker]

So you're saying that if the OP outs an Ashford in his current basement *and adheres to all the (other) instructions in the manual* things should be fine with the stove (even if performance may not meet expectations because the uninsulated environment)?

I.e. no overfire?

 

[BKVP]

Correct.

 

[stoveliker]

Thank you.

OP, bkvp is what his name suggests.
Seems an Ashford would work and your concern is not a problem if you adhere to the manual (as you should anyway).

They beauty is that you can run it a bit harder now but if you insulate you can run it at lower output.

The other concern about basement installs is negative pressure, where your home functions as a chimney (drafts warm air up) which can lead to smoke roll out (or CO).

Hard to say if this would be an issue. If the upstairs and the ceiling to the attic is well air sealed, it may not be an issue.

 

[NewToVT]

I wonder why that existing Vermont castings defiant (i believe) was determined to be "unsafe".
I would definitely have a woodstove down there in that spot.

According to the chimney sweep, it’s a knockoff of a Vermont Castings and had several isssues, I don’t remember the specifics, but he strongly suggested not using it.

 

[NewToVT]

No, polystyrene foam board does need to be covered by drywall (or rockwool) everywhere per firecode.

Regarding external insulation, if there is a vapor barrier there (e.g. closed cell foam board) you don't want a vapor barrier inside in the rim joist (as spray foam would be) because any moisture from the concrete that wicks through the sil plate will have no way to dry out, leading to rotting rim joists.

Before doing something there do talk to a knowledgeable person - noting that many (insulation) contractors are not very knowledgeable.

Regarding the stove, you can still put a stove in without a thermostat. It's the thermostat combined with an uninsulated space that is potentially problematic. A stove without thermostat would work normally.
Problem is that you would have to size it to work with the uninsulated BTU need which would be too much if you end up insulating it later.

6" is good as it works with many stoves.

It was an insulation contractor who suggested sprayfoam at the rim joists. If spray foam isn’t good, and fiberglass isn’t good, what should go there?

We just spent a bunch of money on air sealing in the attic (by a different insulation contractor), mainly because VT has a really good rebate on that, so we were going to wait a bit on any basement insulation, rim joist or otherwise, but good to know for the future.

 

[NewToVT]

Let me add in here:
When someone installs a wood heater in the uninsulated basement, they SOMETIMES complain it won't put out enough heat. These situations don't match expectations of heating FROM the basement.

SOME users are tempted to run the stove other than as directed. Such transgressions include, leaving front loading door cracked open, running stove with bypass open, removing main air tube lid and placing an item to keep thermostat blade open continuously.

This is the reason for the statement in the manuals.

I agree with others, insulate basement walls this year (check for tax credits) and next year run a wood stove. This will also permit sufficient time to build wood shed and fill it.

BKVP

Thank you for the clarification, very helpful!