Moving heat to second level

[Bostonceltics151]

Hello,

I know there are some threads on this already, but I’m looking for some specific advice. I have a big wood stove in the basement, center of the house, insulated walls and ceiling in basement. I’m trying to get more heat up to the main level and eventually up to the second level of the home. I’ve already tried removing large amounts of insulation in the basement ceiling, which heats the floors, but doesn’t seem to do much to raise the ambient temp on the main level. Basement stays a consistent 85-100 degrees, and I want to get that upstairs. I feel as though I’m left with one option; cutting vent holes, just not sure where to cut in order to create pass through for warm air, and a return for cold air. Current we have a kick register under one of the cabinet in the kitchen, and it’s only allowing cold air to flow down, bo hot air comes up. I cannot leave the basement door open at all times, and even when I do it seems to just allow cold air down rather than heat up. Anyone have any suggestions or thought, or know of a consultant that could give advice? Thank you!

 

[DAKSY]

Cold air returns work best when
they are adjacent to exterior walls,
since those walls tend to be colder than interior ones.
If you can get the cold air to drop, the heated air
should come up your basement stairs...

 

[Bostonceltics151]

Agreed, but I can’t leave the door open at all times. Two dogs, and a new baby about to start walking.. wife is freaked out about it and doesn’t think a baby gate will stop him..

 

[DAKSY]

Agreed, but I can’t leave the door open at all times. Two dogs, and a new baby about to start walking.. wife is freaked out about it and doesn’t think a baby gate will stop him..

Maybe if you got another door & modified it with a grate the the child & the dogs couldn't get thru.
Switch it back to the old one when summer comes along...

 

[Rockey]

Put a screen door at the top of the stairs

 

[Bostonceltics151]

Here’s the problem with the screen door or vent in the door.. when the door is open (at night after the little one is asleep) it acts more as a cold air return (you can feel the cold air falling down the stairs when coming up). It seems the cold air wants to just go down.. both the stairs and the kick vent in the kitchen have cold air falling down.. I just can’t figure out how to get it to go up! My thought was cutting 2-3 holes almost directly above the stove (one in the kitchen, one near the stairs going to the second level, both above the wood stove) so the warm air has a path of least resistance and the current cold air returns can continue functioning as they are.. but.. again.. wife doesn’t want me cutting random holes in the hardwood floor or tile.. hence the question; would that work?

 

[Rockey]

If you have cold air going down the stairs, then you have an equal amount of warm air going upstairs somehow. That is a good thing. How well is the upstair insulated?

 

[Olson24]

Agreed, but I can’t leave the door open at all times. Two dogs, and a new baby about to start walking.. wife is freaked out about it and doesn’t think a baby gate will stop him..

I kind of have the same set up and situation. We found a baby gate for stairs that screws into the door Jam on one side, it worked great. Now that we can keep that door open our main floor stays at 72-75 also if you have any rooms in your basement that have doors that don’t need the heat chit those as well. Good luck

 

[SuperJ]

If you have cold air going down the stairs, then you have an equal amount of warm air going upstairs somehow. That is a good thing. How well is the upstair insulated?

True... You want openings where the air is the hottest and coldest to maximize convection. That probably means right above the the stove, and exterior walls as already mentioned. Since you are relying on convection (and not a fan), you need pretty large openings. Convection can move a lot of are but it is limited by the size of the openings since convection won't really build much pressure in a house with the kinda of temp differences we are talking above (stack effect).

There may be fire code issues with cutting openings in floors. But I don't know the details.

 

[DuaeGuttae]

Do you have an infrared temperature gun? Use that to find out where your hottest air is trapped and think whether vents would work there. Then figure out where the coldest air is upstairs that could be channeled to the floor below.

We used to heat a raised ranch in Virginia with a medium insert. We bought it originally to deal with a cold finished basement, but it did such a good job that we moved to using it for most of our heat after a couple of years. It was a little small for our house, but it did admirably, and we used a gas furnace when necessary. Our basement stairwell was open with a half wall at the top, and that helped a lot, but we had a beam that ran across the whole basement and separated the stove from the stairwell and trapped the hottest air at the ceiling downstairs. We cut two vents beside that beam that came out upstairs right into the dining room on either side of the passageway to the kitchen. (We did not put the vents directly over the stove because we didn’t want any child dropping something through them onto a hot surface.) On the far side of the living room upstairs along the outside wall we cut a vent that went to the far end of the stove room. In our case, it helped, and sometimes we put small fans in the vents to boost circulation when the temperatures went to polar vortex or something. (We also talked to our local city inspector about doing this before we did it.)

We spent a lot of time measuring with the IR thermometer to determine the best places to put vents that were also as unobtrusive as possible. We also studied convection patterns in the house with the oh-so-sophisticated method of holding a square of tissue at various levels to see which way the air was moving. Cold air constantly poured down our basement steps, but hot air constantly moved up the stairway above it. I’d say you want a very thorough understanding of how air and heat move now in your house before cutting vents.

If you can’t do a baby gate on the basement (we had one for years on our steps, and it held up admirably), what about a barn door?

 

[Woodsplitter67]

Back in the day before forced heat, the heat from the basement moved from one level to another through a large hole in the floor.. like 2x2 foot. The cut out.in the floor was always near the heat sorce. The cut out had a nice decorative great over top

 

[peakbagger]

The fire code issue is that if you cut holes in floors to move air, those holes make a fire spread far more rapidly. The solution is to cut a hole and put a fire damper in the hole. It is spring loaded to close that is kept open during normal conditions with a meltable "fuse" but closes if it detects hot gases from a fire. They are pretty much standard in commercial construction. You usually need to buy the grille and then make an adaptor to match up to the damper.

Ideally you run the vent from a cold corner to the basement so you dont feel the draft.

 

[kborndale]

Why cant you just leave the basement door open and put one of those wooden baby gates in it? Without the door open I doubt your going to get enough heat upstairs.

 

[Ashful]

Baby gates get old quick. I have two words for you: Dutch door. I installed one on the mud room, where we pen our dogs during the day.

 

[Bostonceltics151]

I’ve considered the Dutch door and baby gate.. however the big issue I’m having is I’m feeling more cold air going down the stairs, than warm air coming up. When I first open the basement door there’s a lot of trapped warm air, but as soon as the draft starts going down the basement stairs, the heat stops coming up.

 

[Ashful]

If cold air is going down, then warm air is coming up. Simple displacement effect. If you’re saying the warm air that’s coming up is not warm enough, then your issue is more about making more heat, than moving it around.

BTW, a Dutch door might not be a great option here, unless the lower half were ventilated with louvres, or something similar.

 

[Bad LP]

I added nice looking grills in a file room door that was to be kept closed but the HVAC return was located in that space.

When I had a stove in my basement I would not get a lot of heat upstairs with the cellar door open. If I turned on my shop air dust remover I could easily run the first floor to 80. Just that little bit of air movement did the trick.

 

[Bostonceltics151]

So I did a smoke test tonight. Air is definitely moving down the basement stairs, and also down the kick vent under our cabinet into the basement. There are no other point where air could be moving upward, so I have no idea where the warm air would be going. As for making more heat, I can’t run the stove and hotter, and it’s a soap stone stove so even when it’s just coals it above 350 degrees before I reload when I get home. Any suggestions where the air would be going, or how to get the hot air to rise instead of cold air fall? No leaks in the basement, it’s well insulated and tight.

 

[Rockey]

Get someone that knows what they are doing to bring an infrared camera over and follow the heat. Ill bet dollars to donuts its going up the top part of the stairwell. There are only two scenarios that are possible.

-The cold air going down the stairwell is being generated by a lot of air entering the house upstairs and finding a large opening downstairs to exit. Therefor no warm air is rising as it is being carried out by the air currents. Do you believe this scenario because I dont.

- The cold air rushing down the stairs is part of the natural heat conveyor that most houses setup when you heat from the lower level. Cold air from upstairs that is dropping down the stairwell has to be replaced with a nearly equal volume of air rising up somewhere, otherwise you would be pressurizing the basement.

Does this make sense? i think an infrared camera would reveal the truth.

 

[wooduser]

we used a gas furnace when necessary.

I've long thought that using a wood stove for base load heating and a forced air furnace to circulate warm air around a house has a lot to recommend it.

A well designed central heating system is really the gold standard for high quality heating. Spot heating with a wood stove is fine, and I enjoy it, but it usually can't match the high quality heat of a central heating system, especially in ranch type houses with hallways and bedrooms strung out away from the stove.

Using a combination of the wood stove and central heating therefore can frequently add quite a bit to a wood stove by itself.

(I'm wondering if I'm going to get flamed for saying there are advantages to a central heating system!)

 

[Bostonceltics151]

There is no central system, it’s oil base board. Also, this we live in a cape, so each floor is the same size, bedroom two floors above directly over stove, stairs on top of stairs.

 

[jimmyb]

hello all - we have a very similar situation. 1440 sqft, 2 story house with a square floor plan and a 600 sqft basement. The center chimney that was used for 100 years to run the furnace for radiators. We have yanked all the hydronics and replaced with a few heat pumps. And this season we lined the chimney and installed a wood stove in the basement. The stove is in the center of the house, while the stairs to the basement sit between the kitchen and the foyer along an outside wall. the basement has been insulated with closed cell so it’s pretty tight now.

Its so great to sit by the fire.

So far when the basement door is wide open we get a little warm air rising which is directed to the kitchen - but with that door open we cut ourselves off from the foyer so we need another way. The floor is original hardwood with a T&G sub floor and the kitchen is tiled. We have 4” of sound batt in the joist bays and my wife wants to pull that so that floor can be warmed by the stove. Not sure what would help unless we did as others suggest and cut a 2x2’ hole over the stove and two more 1x1s at the outside walls for cold air returns.

That said, thinking about how to do this with smaller holes. What about encouraging convection by pulling cold air into the basemnt using small diameter flex duct and small fans pulling cold air off the first floor down to the floor of the basement? is there anyway to compute the amount of ducts and fans that would be needed to exchange the air at a decent rate? seems like if enough air is forced down the heat will be more likely forced up the staircase and we can modify the basement door to let it flow. for what it’s worth we also have the center beam problem - some of the heat is certainly being blocked by the beam. and since the ceiling of the basement isn’t finished yet i guess some of the heat is trapped in the joists bays too.

thanks in advance for your insights and ideas on this.

 

[peakbagger]

I have a friend who heats his ranch with a wood stove in the basement. He has standard oil fired hydronic system for backup when he goes on vacation in winter and in shoulder seasons but with only one flue and no interest in burning lots of oil he built his own heat transfer coil that sits on top of the wood stove (an old Fisher clone). The heat exchanger made out of slant fin sits on top of the stove (the hottest part) and there are concrete blocks on top of the heat exchanger to keep it in contact with the top of the stove. He has an aquastat on the heat exchanger outlet that turns on a pump that tees into the hydronic system and runs as long as the wood stove is running. This circulates heat through the baseboards distributing the heat into the baseboards. He also has a dump zone in a normally unheated space under an addition for when the house is not calling for heat and a backup T&P safety relief on the coil. It definitely has some Rube Golberg attributes but its worked for more than 30 years. He on occasion has opportunities for free heating oil from tanks that need to be removed so most of his heating oil he does use is free (except the time to pump it out and drive it home). It works remarkably well once there is consistent heating demand. Most of the parts were scrap he hauled home. In case of power outage he has isolation valves and quick disconnects on the heat exchanger so he can remove it and heat with wood with no power (he also has a generator so its backup to backup.

 

[stoveliker]

A warm floor won't radiate much into the upstairs rooms. You want convection. So pulling the insulation will feel nice to your feet, but won't heat the rooms there much.

I do exactly as you proposed. I have a central stairs from the basement. I made a register in the main floor centered near a wall, away from the stairs. Added a boot, ran a metal duct thru the joists to the side wall of the basement, added a fire damper (see below), followed by a flexible duct down to the basement floor where I added an inline fan, another boot and register.
This sucks cold air from the LR floor and deposits it on the basement floor. This pushes the warmest air (near the ceiling in the basement) up the stairs into the main floor of the home.
This is how I heat my home with the wood stove. I have an 825 sqft basement, a 1200 sqft ranch on top, with another 500 sqft second story addition on top of that.

The fire damper (and metal ducting any place between floor register and damper) is important and may be required by code. A hole in the floor helps heat flow, but it also allows fire to spread quickly.

I mounted the fan bolted to (a wood frame bolted to ) the concrete floor. It only has flexible connections to the fire damper and the register in the basement. This is to reduce any vibration noise traveling through studs (I put all this in a chase) into the floor joists and into the LR floor. I can't hear anything in the LR other than a very light swishing of the air flow through the register on the LR floor.

 

[tabner]

@jimmyb
Green mountain 60 or 40? I heat with the GM 60, from my basement. i also pulled out my hydronic system and put in mini splits, and then wood in the basement. Similar setup. About 1700 square feet here. How is the stove running for you? Any issues with draft or smoke roll out?
To answer your question, yes, I have an air flow design similar to what you are describing, and yes, there is a way to calculate the air flow amounts.
My first floor (above basement), is laid out like a horseshoe, basement stairs come up into the living room which wraps around to dining, kitchen, and then back bedroom. Back bedroom is the coldest, so I cut a 14" x 6" grill in the floor, bought a floor/register grill cover that converts to 8" dia underneath, attached an 8" flex duct pipe on that which runs down to about 4 feet off the floor and then has an inline duct fan pointing down on it (on temperature sensor) and then more 8" duct to a wall grate pushing air out into the backside of the basement.
Those inline duct fans say how many Cubic feet of air they move per minute, in the item description/specifics. As long as none of your duct work or registers are smaller than the surface area of 8" dia, it should theoretically move as much as it says. And then if you calculate out the cubic footage of your first floor, you can calculate how many minutes it would take to recirculate all that air. There would be some minor differences here between colder air on the return being denser, and warmer air coming up being less dense, etc, but I think that's minimal enough to be irrelevant here, you're just looking for a ballpark. The floor register was about $20, the uninsulated flex duct was $25, and the fan was kind of expensive, but i think worth it, i put a photo below. It comes with a temperature sensor which i ran through the ceiling into the stove room, so it kicks on when the stove room hits 75 degrees. The basement is still in the mid to high 80s when the upstairs is 70, in cold weather, but i'll take it, works for me.