Burn Rates/Heat Output

[rvasupersport]

First off I just gotta say I love having a pellet stove!

My Quadra-Fire has a high medium and low heat output setting. Is it more efficient to keep it on a high setting making a larger fire letting more heat come into the room and have it cycle on and off more or leave it on a low setting for a gradual climb in temp.

I am curious if one way will conserve pellets more than the other.

Thanks
Jason

 

[chrisasst]

i assume you have a thermostat? If so I am wondering the same thing.

 

[pelletfan]

If it is quite cold in the morning, I run it for a while on a higher setting to warm up the room.
Than throttle back to a medium setting and from there down to low.
But it all depends on outside temperature and if you have a good insulated house.
If you don't mind a colder room you can run it just on medium. Just takes a little longer to get up to temperature.
Guess it's all a personal preference.
With Oil I had the rooms mostly only on 68F never higher, now with that Stove I stupidly like to run in the 70F, figure out why????

 

[sydney1963]

72 degrees feels good to me now when last year 62 felt warm.

 

[Valhalla]

Pelletfan,

You have in place and use a great heating plan for your stove! I like it.

Yes, we reach for the higher rooms temps, well into the 70s because it is so easy.
All by our personal preference.

Well done and keep warm. That is one fine stove!

 

[welshcob]

I've been trying to figure out the same thing. I'm running a Quad Santa Fe in the living room with a programmable t-stat in the next room. So far I've kept the stove on the Medium switch setting, dropped the temp to 63 at night and while I'm at work, cranking up to 68 morning and evening. Stove cycles on and off just fine as long as I remember to keep the hopper filled.

As it gets colder here in the Albany, NY area the stove has to work harder/longer to get up to temp when it swings from 63 to 68, so I'm wondering if I might be better off running the stove on low and just keeping the t-stat at 68 all the time. (For sure the dogs would be pleased!) Has anyone tried this, or do I need to perform my own science experiment?

I love my Quad, BTW. Burning Clean Fire pellets, which do seem to produce a surprising amount of clinker and ash but I find very little fines in the bags and the Quad is able to handle even the occasional 2 inch pellet without choking.

 

[pelletfan]

Has anyone tried this, or do I need to perform my own science experiment?

You probably be better off to try your own science experiment, without being sarcastic about it.

As our homes are all quite differently build, every set up will have to be a little bit different. Nevertheless
I find it's great just to exchange ideas and draw your own conclusions to solve our challenges in working the
Wood Pellet Stove efficiently.
Let us know how it works out

 

[hailfire]

If I remember correctly, programmable setback thermostats were reported to
make the most improvement in climates where the temperature differential wasn't as great.

I'm in Northern NJ and I find that when using the setback, if I let the temperature fall
back to the 55 degree mark, the furnace (or any heating appliance) takes a long time running
to get back up to 68 degrees. So if the setback period in only 6-8 hours, I'm not sure
the savings are significant. Now that I'm converting to a PF100 pellet furnace, I'm first
going to test keeping a narrower setback range, like 62 while away and 72 while home.

To really experiment with this concept, you'd have to take careful measurements of pellet usage
and degree days and so forth to see what works best for your home.

Hail

PF100

 

[Shortstuff]

I have to say that we are still getting used to this "new" way of heating with our free-standing Castile. So far, we are more than pleased with everything about it. Rather than using our cast iron baseboard which heats evenly and holds the heat for a very long time, now we have one source, one location where the heat comes from - the convection blower only.

Over the years we've always kept our baseboard heat set for 70° during the day and 68° at night and never really felt comfortable, but managed. Now with the Castile, we have it set for 68° during the day and 66° at night and it actually feels much more comfortable, it feels like it's so much warmer than the temperature says it is.

I leave the stove set on medium all the time and give it a good cleaning every 3 to 4 days and it has worked flawlessly. With temps near freezing at night and 50° to 55° during the day we're using less than a bag a day. I have thought about dropping it to the low setting, but after reading so much here I'm guessing that I would end up with more soot than I want and a less-efficient burn.

Happy heating!

Steve

 

[Jester]

72 degrees feels good to me now when last year 62 felt warm.

I had this discussion with my wife last night as she was feeling chilly and pulling on a blanket at 74.

 

[welshcob]

if I let the temperature fall
back to the 55 degree mark, the furnace (or any heating appliance) takes a long time running
to get back up to 68 degrees.

Gosh, Hailfire, that seems like a HUGE jump. Of course my history with the programmable t-stat is with the oil furnace and cast iron radiators but that being said, I found the sweet spot to be about a 3 to 5 degree differential. That is consistent with everything I have read. So far with the pellet stove I am seeing considerable reduction on pellet usage since the stove shuts down and rests quietly for hours while the temp in house drops 5 degrees....as it gets colder outside I expect to lose this advantage and at some point the poor stove will be firing all the time just to maintain a comfortable temp and in extreme cold and/or wind the oil burner may need to supplement. (200 year old, 1200sf house)

The downside of the programmable is that the thermostat tends to run your life. When the temp drops in the evening it's time to go to bed, when the stove starts to crank in the morning it's time to get up. Of course I can override the pre-set temp at any time, but then that involves remembering to cancel the override.

 

[mcmanus]

If I remember correctly, programmable setback thermostats were reported to
make the most improvement in climates where the temperature differential wasn't as great.

Its usually the other way around with respect to heat loss.

Bigger differentials in inside vs outside cost exponentially more to maintain than smaller ones. Another way of putting this is that the energy required to maintain a house a +50 (compared to the outside) is significantly more than double the energy required to maintain a house at +25. That seems wrong at first, a BTU is a BTU right? It is, but the rate at which the heat is transferred from the inside to the outside (i.e. lost) is proportional to the difference in temps - that's Newton's Law of Cooling.

It's kind of intuitive - you take a pizza out of a 450 degree oven. It's blistering hot. But pretty soon you can eat it and it has dropped 250 or 300 degrees. But its a much longer time before it is at room temperature, even though that is just 75 degrees away from that point now. At the higher differentials just out of the oven it lost heat to its environment faster.

This is a really neat visual. The area under the curve is the heat loss over time. The unit of time will depend on the house's R value, but the shape of the curve will be the same. See how much more heat is lost in ".2T" with a large differential than a small one.

Which brings us back to the setback thermostat. They work in general by lowering the overnight temperature - which of course means that during those hours the in/out differential is less than if the thermostat had been left at a constant level. The lower differential means a lower heat loss rate over night. In the morning you have to pump a bunch of energy into the system to get back to the 'normal' setting but that amount of energy is less than it would have been if you had been heating all night long because the loss rate was lower.

It works especially well in areas with high differentials you are effectively reducing a +50 to a +35 for the overnight period. Reducing from +30 to +15 doesn't save as much energy, even though in each case you might be setting the thermostat back from 72 to 57.

It is the same reason that turning the thermostat down from 73 to 71 saves more energy than turning it down from 68 to 66, even though its still 2 degrees in each case. That last degree is always the most valuable one you can save.

 

[Shortstuff]

Keep in mind also that it's not just the air temperature that you are trying to increase, it's everything in the room: furniture, appliances, walls, drapes, carpets and floors, cabinets, that half-can of soda you left on the end table last night. Everything in that room is at whatever temperature you start at and has to be heated up.

Happy heating!

Steve

 

[slls]

I run mine on medium and high fan, it seems to burn clean on that setting.
I am curious if medium will be enough when the weather gets cold.
I run mine 24/7 at 70 deg, old people like to be warm.
Have burned 13 bags since 10-9 heating 24/7.

 

[rvasupersport]

The big question I have now is do I run the stove all day or just when I am at home?

I have my stove hooked up with a programmable tstat and have been only running my stove when I am at home from 6pm-7am. When I get home the temp inside is about 60 and I have the tstat programmed to kick on at 6pm and warm the house up to 69. From what I have gathered is that it will be more efficient to run the stove while I am not at home but on a lower temperature setting? So when I am away run the stove at 65 or something? Not sure how good my pellets are but it would be normal to burn 1 bag per day?

 

[gw2kpro]

I think the larger overall question has to do with efficiency.

If you take a 40 lb bag of pellets and burn it in a typical stove on a low heat setting, it is going to burn for a long time (say 36 hours) and during that time X number of BTU's are going to be released into the room.

Let's say that you take that same bag of pellets and burn it in the same stove on the stove's highest setting. It's going to burn for a much shorter time (say 10 hours) and during that time Y number of BTU's are going to be released in to the room.

Does anyone know which (X or Y) should be higher? Does anyone know whether a typical pellet stove would be more efficient at high burn rates or low burn rates?

 

[hossthehermit]

I think the larger overall question has to do with efficiency.

If you take a 40 lb bag of pellets and burn it in a typical stove on a low heat setting, it is going to burn for a long time (say 36 hours) and during that time X number of BTU's are going to be released into the room.

Let's say that you take that same bag of pellets and burn it in the same stove on the stove's highest setting. It's going to burn for a much shorter time (say 10 hours) and during that time Y number of BTU's are going to be released in to the room.

Does anyone know which (X or Y) should be higher? Does anyone know whether a typical pellet stove would be more efficient at high burn rates or low burn rates?

You also need to consider W number of BTUs released out the vent on low, and Z number of BTUs released out the vent on hi

 

[kbjelka]

First off I just gotta say I love having a pellet stove!

My Quadra-Fire has a high medium and low heat output setting. Is it more efficient to keep it on a high setting making a larger fire letting more heat come into the room and have it cycle on and off more or leave it on a low setting for a gradual climb in temp.

I am curious if one way will conserve pellets more than the other.

Thanks
Jason

Hi Jason, I have a Quadra-Fire Castile and what the installer told me regarding the heat output setting has seemed to hold true. He said generally speaking run it on low before Thanksgiving and or above 40 degrees, medium after Thanksgiving and or below 40, and high when you get a real cold snap. Seems to be spot on for my house.

 

[rvasupersport]

First off I just gotta say I love having a pellet stove!

My Quadra-Fire has a high medium and low heat output setting. Is it more efficient to keep it on a high setting making a larger fire letting more heat come into the room and have it cycle on and off more or leave it on a low setting for a gradual climb in temp.

I am curious if one way will conserve pellets more than the other.

Thanks
Jason

Hi Jason, I have a Quadra-Fire Castile and what the installer told me regarding the heat output setting has seemed to hold true. He said generally speaking run it on low before Thanksgiving and or above 40 degrees, medium after Thanksgiving and or below 40, and high when you get a real cold snap. Seems to be spot on for my house.

Thanks! I have been running it on medium from 5pm-7am daily. Going pretty smoothly. Hi temps are about 50 and lows around 30 so I guess I am right on track. Still not convinced to burn 24/7.