Rising Heat

[makato]

My house has a large Vermont wood stove in the first floor boiler room. All the living area is on the 2nd floor. Basically the stove is overkill because the heat build up is really wasted below. There is a stairwell that rises to the 2nd floor and the way the room was built much of the heat gathers along the ceiling and under the stairs. Yes, there is heat transfer up the stairs but I would like to maximize this since all this heat is available.
I'm thinking of installing grates or registers in the top 2 kickboards to allow all the heat gathering under stairs to flow through less impeaded. Does anyone have any thoughts on this? I'm sure this brings allot of questions so instead of trying to write a book, I'm providing the basics. Its a poor design since I have zones for hot water heating in the garage on one side and a small attached greenhouse on the other side of the house. It gets so warm in the boiler room, the thermostat can't react to the need for heat in the garage. This is a gambrel style house again with hot water baseboard heat and all the living area upstairs.

Thanks.....Makato

 

[WILDSOURDOUGH]

Common problem- You are not alone.
Grates in the floor between the floor joists would help, as would registers in the kickplates-
but to really get the heat upstairs ( or anywhere for that matter )- you need air movement, as in fans and blowers.
Have you considered moving the therostat to a better location ?

 

[JohnnyBravo]

if u add pasive air passage at one end ie. frome under the stairs. it would help a lot to add a second passive or if nessisary power assisted return air route.

 

[nshif]

Cutting holes in floors and stairs is really not a good idea from a fire spread perspective unless they are thermally fused. ( costly ) I would try fans 1st but move cold air down stairs rather the hot up. The cold air moved down will force warm air up

 

[Gooserider]

Nshif has it right - use fans to get the air moving, and usually it is better to push the cold air into the stove room than it is to try and force the hot air out.

Cutting holes in the floor is a VERY BAD idea, that keeps coming up over and over... It destroys your fire containment and can greatly reduce the time you would have to evacuate in the event of a fire. Even worse (and something that is NOT helped by fusible links) is that if you have a CO leak for any reason, a register can aid in the spread of toxic fumes into your sleeping areas.

We know that it used to be common practice, but we have learned better over the years because people DIED doing it the old fashioned way...

Gooserider

 

[thephotohound]

Wait for Elk to get a hold of this one....

 

[makato]

I can appreciate all the safety concerns as this has been #1 on my mind. Since everything is now rising up the stairwell, Its hard to think a couple grates would make that much difference. It would only allow the heat at the ceiling level to pass upstairs less impeaded.
I have every conceivable detector in the downstairs hall and upstairs should any smoke or CO2 pass. Plus I have heat detectors tied to the security system should a high heat fire brake out. The room is a 15x16 space with a 12ft ceiling. Its more L shaped with the chimneys and stairs taking space to the right as you walk in the door. Cool air can cycle into the room through windows on the garage side wall and/or the green house side wall so there really isn't any return from the upstairs. Using small fans I have at the window corners, I can also send heat into the garage and green house and let the cooler air pass through the doors into the hall and back through the door of the boiler room. The heat rises into the upper living space and is cycled by ceiling fans.
I guess my thought is releasing some of the heat from the room downstairs and using it upstairs through passive action or a register with a fan on the back to suck it out.

Makato

 

[Rhone]

You can cut holes and put in fans but, the heat likes to stick on the floor it's created. My previous house I had the stove in the basement, had to keep it around 90F to have the floor above be around 72F and the floor above that was 55F or so. I added 2 ducts that went from the top floor to the stove and three ducts that went to parts of the first floor to the stove, the best part was I hooked up a kitchen hood over the stove and put all this piping to it. Think it should've made a huge difference? Didn't actually. All that work, the basement was still too hot and the top floor still too cold, the end result I lowered the basement temps a measily 5F and increased the top floor 5F (I had to keep the basement 80-85F or so and the top floor lingered around 60F... always upsets me how much work I put into it, only to be one of the biggest let downs of my life). I added a heat activated fan to it, hardly any improvement. So, I wish the best of luck.

 

[slowzuki]

If you are trying to move the air, you need almost the cfm's that a regular forced air furnace can provide. A little 50 cfm stove top hood will not move enough air. You can use your stair for the return air or the new ventilation for return air. Make sure your house has proper smoke detection. You mention you already have CO detection.

Ken

 

[gpcollen1]

I put in a doorway fan to blow air upstairs. It is only 65cfm but it works rather well. It keeps the room from being unbearable when burning early and late in the season and it does a fair job of moving air period!

 

[Todd]

My stove is in my finished basement and heats it and the upper main level within 5-8 degree temp difference. Also have a floor vent above the stove with small fan inside that blows warm air into upper living room. I get a good circulation of air between the open stairwell and floor vent. If you go this route I recommend vents with fusible links to close in case of fire and also smoke/fire detectors. It may be an old fashioned idea but it works, and a properly installed and operated EPA stove reduces the risks of fire or toxic fumes.

 

[WILDSOURDOUGH]

All true statments-
My experience has been that when you try to pull (or push) warm air into colder air- the warmer air tends of get cooled ( maybe by the fan/blower- maybe by resistance to the cooler air (Density ?))
Still true that you need two paths for the air to flow- into and out of the area with the stove.

 

[elkimmeg]

These post amuse me got a question for all have you ever seen radiators baseboard radiators mounted at ceiling level? I wounder why they are mounted at the follr level?
as heat rises out the top vent opening it pulls in the cooler floor level air which exits being heated they are designed that way to distribute and even heat flow
the next question is what good are ceiling feeds how does that air get drawn down to replace the cooler heavire air Oh I get it with ceoling returns? the ceiling returns return the hotest olready heated air.
the only worse design is the upstairs central hall design practically useless for drawing the cooler air which is what your return should be doing.

What amuses me most is the ability or returns being able to distribute heat a purpose they should never be able to do Shows just how poorly designed your HVAC system is designed no wonder you want or need an axhilliary heater to make up for huge deficiencies of a poorly designed HVAC system. I would think one would be better off redesigning an efficient system than pouring money for backup heat Really if a return can distribute heat than it is a complete failure. It h should be designed to remove cool air Then there is the safety factor never built in or even considered on the return side many systems use porous leak joist bays for returns there is no worse way than to use joist bays no safety built in built with combustible materials

In my town every bedroom has a return not some central hallway return but a separate return duct Till code addressed design most Hvace systems are designed so bad they loose 35% of heat in transmission due to leakage poor design bad duct routing and poor choice of difuser locations.

 

[MrGriz]

Ok Elk, I'll bite and play devils advocate for a moment.

we'll use my situation as an example. Insert in the basement of a tri-level, opposite an open stairwell to the main level. Above the basement room with the fireplace is the family room and kitchen / dining area. Currently, heat rises up the open stairwell at the ceiling and cool air flows back down the stairs at the floor. It really does a good job of keeping the main level warm.

If (relax I said if) I cut one or two registers in the ceiling of the basement on the wall above the stove (across from the stairs) wouldn't that allow warm air from the basement to rise through the registers and displace more cold air down the stairs and back to the stove? I understand the dangers of doing this (path for fire to spread and CO to move, etc...), but doesn't it work in theory?

 

[makato]

Ok, gang, I'm all about the safety issues so can someone point me to where I can purchase the registers with fusable links? I've got about a 6x12 inch space on each side of the stringer where I can install a register in the kickboard of the top step. I'm feeling very confident I'm going to get significant heat flow just through natural draw especially since the room is 15x16 with a 12' ceiling. There is allot of built up heat rising. I guess the bottom line is I can maximize every bit of heat available from the wood stove and save on oil.

 

[Todd]

Ok Elk, I'll bite and play devils advocate for a moment.

we'll use my situation as an example. Insert in the basement of a tri-level, opposite an open stairwell to the main level. Above the basement room with the fireplace is the family room and kitchen / dining area. Currently, heat rises up the open stairwell at the ceiling and cool air flows back down the stairs at the floor. It really does a good job of keeping the main level warm.

If (relax I said if) I cut one or two registers in the ceiling of the basement on the wall above the stove (across from the stairs) wouldn't that allow warm air from the basement to rise through the registers and displace more cold air down the stairs and back to the stove? I understand the dangers of doing this (path for fire to spread and CO to move, etc...), but doesn't it work in theory?

In theory yes, but houses like to do funny things. Those vents may push the cool air down over the stove and more heat up the stairwell or vise versa. I've done it in 2 different homes and they both acted differently, but luckily it worked out for me.

Here is a link for fusible fire dampers.
www.atlantasupply.com

 

[thephotohound]

Am I the only one who doesn't know what fusible links are? And do all of the grills on that site have them?

 

[elkimmeg]

Ph fusible link lets say you have a spring loaded damper that has a link that melts out at 130 /140 degrees once that link melts it releases the spring and closed the damper at that point it prevents the spread of smoke and fire

 

[rmcfall]

I don't want to hijack this thread, but are registers with a fusable link recommended in the case of a conditioned crawlspace with passive registers in a concrete wall dividing the crawl and living areas of a basement? I posted this question in the DIY forum, but didn't get a response. Again, not wanting to hijack this thread, but thought this seemed like a good opportunity to ask...

 

[Gooserider]

I don't want to hijack this thread, but are registers with a fusable link recommended in the case of a conditioned crawlspace with passive registers in a concrete wall dividing the crawl and living areas of a basement? I posted this question in the DIY forum, but didn't get a response. Again, not wanting to hijack this thread, but thought this seemed like a good opportunity to ask...

Elk would know better if they were required or not, but I don't see how they could possibly hurt... The whole idea is that the more you contain the smoke / fire, the more time you have to get you and your family out, and maybe even give the guy's with the red trucks more of a chance to put a damper on things before the entire house goes up.

Gooserider

 

[MrGriz]

Thanks Todd. I'm not planning on cutting any holes in the floor at the moment, just thinking out loud about the air flow that's all. It seems like every time the topic of moving heat comes up it goes back to the fact that you need to provide adequate return of cold air for the amount of hot air you displace. It just seemed to me that this would be a way to create that path. I suppose once the path was there, the air could move in either direction, ultimately achieving the same result.

I'm still not comfortable with cutting holes in the floor for the containment reasons. The fusible links do make things a bit safer, but are still not as good as the original construction.

 

[elkimmeg]

Nobody has adressed how ,cutting holes in the floor and dealing with pressure gradient issues the lower pressure in basements to higher in the floors above.

at what point will it take for the heat to rise to overcome higher pressuer from above wanting to decent to the lower pressure area below? Maybe some one should figure that out before holes are cut. Like most people cutting hole they do not consider what really involved personal safety a proper return route dealing with pressure differentials. Calculation of volumes

A lot of re-engineering of homes is being done haphazardly without any knowledge that I think it might work at the risk of personal safety Man I would want a bit more info than ruining floors and safety