Fuel usage with a Stat control Vs constant fire

[Snowy Rivers]

I thought I would write some Observations and opinions on the pros and cons of running a pellet stove on a thermostat as compared to runing a stove constantly.

We have used our Quadrafire 1000 since purchasing it new back in 1994.

For several years the Quad was the main workhorse used to heat the 2400 Ft ranch style home.

The Quad as many know, runs on a T stat and comes on and off as needed. The variation in room temps will vary about 5 degrees or so from the time the stove turns off until it comes back on again.

The T stat is located centrally to try and keep the house temps more even.

We currently have two whitfield manual lite (constant run type stoves too.

What I have observed is that with the Quad, the temperature in the outer areas tends to stay cooler and the overall "comfort" is not as good with the Stat controlled stove.


Everything in the room adds to or subtracts from the temperature. The contents of a room (furniture) acts as a giant heat sink. If the whole room cools off, it takes far longer to get it back up to temperature.

For example
The room has cooled down to say 65F and stayed there for a few hours, the stove comes on and the room "AIR" is heated back up to 70F, the stove turns off and the "Gaint heat sink" starts to suck up the heat over the next few minutes or hours.

The amount of heat required to get everything back up to the "comfort zone" is far more than what was added to the room during the controlled burn of the stove, that may last only a short time.

I have found that once the rooms and the contents are up to temperature, it takes far less to maintain this than always trying to "Catch up"

Once we get the house at around 70F our small stove can maintain this easily on a fairly small amount of fuel (stove running on low continuously)

When the outside temps fall off drastically, of course it takes more fuel to heat the house but, the contant burn of the stoves keeps the drafty feeling away.

The overall comfort seems to be much better with a constant fire than with the on/off cycling of the Quad (or any stat controlled stove)

During the shoulder seasons this is not so much of an issue, as the heat loss is much less.


During some particularly cold weather, I have observed that as soon as the Quad would shut off, the feelings of cool drafts would come in almost immediately.


There is surely the need to have a Stat on a large stove as it, even on low, in many cases would be way too much heat for the given footage its heating.


Just some thoughts on keeping a large home cozy without being too hot or too cool.



Snowy

 

[dragracer300]

My stove never shuts off with t-stat its just goes high low flame.

 

[THE ROOSTER]

I run my Harman on stove remp 98% of the time, I have tried to use the room temp with a stat, but the fan going on and off over and over drives us crazy... My stove burns much hotter in room temp. but I have found that I only need to use it when we have a power outage and my heat pumps are down...
As you can tell, mine is not used for the only heat source...

 

[jtakeman]

There is going to be 2 sides on this fence. And maybe an in between(me)! I have done both and it depends on lots and lots of factors. I save fuel with the Auto/Off stat mode in the shoulders as my beast eats hardy. It only goes to High/Low stat mode when the daytime high goes in the low 30's. Burning a stove on low for 6 hours at 1.7LBS/Hr = 10.2LBS of fuel. And the house temp is raised with an easy 2 hour medium burn at 3.6LBS/HR = 7.2LBS of fuel. 3 LBS of fuel per day adds up to much savings for me over the season. The stove has the stat option so I use it! Why have the house at the toasty temp when your at work? Just doesn't make sense to me and never did! When I retire maybe, But thats a while off for me.

If the stove doesn't burn low enough you will need to use a stat(or roast). No different than the oil/gas/propane inhalers that lie in the basement. Burning a stove on low for long periods also has its draw backs!

 

[Snowy Rivers]

Good points

My thing is this.

When we get home at around 6:30 PM or so, we want to get comfortable (take a shower and get into night clothes) eat dinner and watch a little tube.

If the house is 64-65 degreesF when we get home, its going to take some serious burn time to get the place comfortable again.

When I get up in the morning at around 5 AM I want to come out of the bedroom into a warm house, adn have little more to do than check the hopper and maybe stir the fire pot a tad.

2400 Sq Ft on a one level Ranch floorplan is a challenge to keep comfortable throughout the house.

I will admit that every floor plan has its "Thing" and a certain sweet spot if you will.

One thing that is a constant though, once the house and iys contnents cool off, it all has to be warmed back up again.

I remember a few years ago, my daughter and Son Inlaw got their own place and were moving.
This was right in the moddle of the winter.

They were in and out all day and to save the stove (Quad) running all the time, they shut it off.

We came home many hours later and the house was only 52F and it took waht seemed an eternity to get this BARN back up to a comfortable temp.

All the furniture was cold, the floors, the walls, it all had to be brought back up to temp.]

Now this is of course the worst case scenario but it does bring home a point.

Had the kids just fired off the large stove and let it run, the temps would have been better, even with all the In/Out traffic during their move.


The stoves that have the High low feature definately fall right into what I am talking about.

The low burn mode will keep things from the drastic temp swings.


I just took the time to do the weekly cleaning of the Advantage II . Last night was in the 30's F so we ran two stoves on low.

The rooms were at 72F this morning at "Cleaning time" I shut the Advantage down and waited for an hour for it to cool.

The little stove was still running while I did the work.

By the time I was done, (total of 2-1/2 hours maybe) the family room had cooled off to around 67 F and the living room (where the little stove is) was down to 69F


With the larger stove back up and running the temps recovered fairly quick and I shut the little one off for the day.


I guess I just appreciate an even heat rather than UP and DOWN and so on.

During really cold weather (teens or below) if the house cools off much, it will take all three stoves to get the temps back and then two to maintain it.


Just some thoughts

Snowy

 

[jtakeman]

Good points

My thing is this.

When we get home at around 6:30 PM or so, we want to get comfortable (take a shower and get into night clothes) eat dinner and watch a little tube.

If the house is 64-65 degreesF when we get home, its going to take some serious burn time to get the place comfortable again.

Snowy

Snowy, These new fangle programable stats can do that for you and manage the away temp too. You just need to figure out the stoves reaction time. My beast raises the house temps 2ºF per hour even in the 20's. Even with a no-no basement install even. Shame on me!

When I go to bed the stat drops the house to 68ºF and before I rise the stat brings the temp up to 72ºF. Once I head to work the stat has the temp back to 66ºF and About 2 hours before I come home the stat has the house rising back to 72ºF. I only need to tinker with it if I take a day off(play hookie from work). My weekend is similar but awake time is a little later!

A properly sized stove works very much like a big ol' furnace. A stove thats too small well you know, chungs for hours on end before you see much temp rise!

P.S. If I was paying what you are for the nutshells, I might be more on your page. But my fuel is much much more Soooo! I must be frugal too......... :cheese:

 

[Snowy Rivers]

I do understand what ya mean when it comes to the cost.

We ran the Quad for many years (pellets only) and would go through a bag to a bag and a half a day during the winter.

Right now I am running a 5 gallon soap pail full of shells for a 24 hour day.

The shells dont fall down evenly but instead leave a huge depression in the hoppers center area.

I fill the hopper in the morning and again in the eavening.

Unless I do a careful measurement its tough to say exactly how much feeds into the fire.

I can probably turn the thing on without the fire being lit and measure what falls into the burn tray over say 5 minutes then do the math, it will be close.

Looks to be about a scant teaspoon full every 8 seconds on low burn.

Here is a typical fire on the lowest setting (runs there most all the time)


I do know that the house is a lot more comfortable with an even heat when running the Whitfield/s than with the Quad.

Takes more fiddling though for sure to keep the Whitfields full, the pots scraped every 8 hours or so.

As you mentioned and I will agree, the cost is far less for the shells than for the pellets.

Cost in dollars Vs cost in time and effort (really not much) to do the shells over the pellets.

The Picc's show a normal fire here in the Advantage running on low.

The number two setting will get things cooking (no pun intended) a lot more and number 3 will really get it HOT

3 makes the stove stink due to the heat level (Normal hot stove smells)

I basically have only one fan setting now on this stove. The Triac is not working me thinks and the fan runs at what I believe is near full speed.

This is fine for now but, I will change this stove over to my new controls eventually and install a separate room air fan speed controller.

 

[Don2222]

Hello

Great info guys, very helpful in understanding how these stoves work and save fuel.

Since we have someone home all day, we choose the low 1.7lbs/hr burn in the cold months.

Then during the shoulder seasons we use a programmable thermostat as a timer to keep the stove on a low burn during the night and then just shut off during the warmer daytime temps. By using the thermostat as a timer, the stove can come on ahead of time to get things warmed up when needed.

So since my oil thermostats are still set to OFF (Only used for DHW), I called the oil company and stopped auto delivery! I asked how much the oil is and she said $2.85 per gallon cash price. So I said no thanks I will wait for spring and cheaper oil prices!

Thanks again guys for all your help and information.

P.s. Just got a dozen pellets of another Bob Kraft Corporation Co. -- Maine Choice pellets from Switch-Em-OverchargEm Lowes. They ran out of Infernos. But even though the sign still said $5.97 per bag, I should them my receipt from last time of $3.36 per bag. The cashier scanned the old Lowes receipt, the manager came and punched in the price override authorization and everyone is happy.

Go Patriots

 

[ablejoy]

Snowy

How often do you need to clean your vent pipe of ash, I just cleaned mine after 25 bags got a tremendous amount of ash. I 've been burning on low and med. with a T- stat got a lot more ash in the pipe then last year using same brand of pellets. Wish I could get the shells like you at a good price none in this area. My house is about the same size as yours only heat the main part of house living room kitchen and dinning room. Stove does a good job we have yet to fire the propane heater when the temps drop in low teens will use the main heater as a backup.
I like the T-Stat I think it saves pellets and the house stays warm 24 hr a day.

 

[ablejoy]

Snowy

How often do you need to clean your vent pipe of ash, I just cleaned mine after 25 bags got a tremendous amount of ash. I 've been burning on low and med. with a T- stat got a lot more ash in the pipe then last year using same brand of pellets. Wish I could get the shells like you at a good price none in this area. My house is about the same size as yours only heat the main part of house living room kitchen and dinning room. Stove does a good job we have yet to fire the propane heater when the temps drop in low teens will use the main heater as a backup.
I like the T-Stat I think it saves pellets and the house stays warm 24 hr a day.

 

[tjnamtiw]

I thought I would write some Observations and opinions on the pros and cons of running a pellet stove on a thermostat as compared to runing a stove constantly.

Just some thoughts on keeping a large home cozy without being too hot or too cool.



Snowy

Those are some good observations, Snowy! I have often wondered about the 'heat sinks' too. I have been letting my house cool down to 69 at night and then in the morning, the Stat runs it back up to 74 (wife...................) but it takes a looooong time to get there with, like you said, a couple of fairly quick starts and stops. This might give me something else to play with.

good observations and good write-up.

 

[SmokeyTheBear]

One of the reasons it takes so long to heat a place up after allowing it to drop is the amount of time it takes to move the air in your house through the heat exchanger.

This the other part of the heat extraction game you have to deal with.

 

[tjnamtiw]

One of the reasons it takes so long to heat a place up after allowing it to drop is the amount of time it takes to move the air in your house through the heat exchanger.

The is the other part of the heat extraction game you have to deal with.

Yea, the cfm is much smaller than a whole house HVAC system so you're right! Didn't think about that. %-P

 

[Snowy Rivers]

My stoves generate a lot of ash using the nut shells, two, maybe three times as much.

My stoves are direct vented so I just stuff the shop vac hose in them every couple weeks and suck em out.

The only downside of a pellet stove isd that there is very little raidiated heat.

Now I have noticed that the pipe that comes off the stove does get fairly warm, possibly a extra heat exchanger that clamps to the pipe could get some more usable heat out of the thing.


During the shoulder season the little prodigy on low is more than enough stove to heat this whole house.

I weighed a pail of shells tonight. Right at 22 pounds for a 6 gallon costco wash soap bucket filled to within 2 inches of the top.

We use 2 pails a day. So just about the same weight as a bag of pellets.

The pails will vary some in weights as I dont always get them the same.

I screen the stuff to be sure there are no sticks or ??? large crap and the process of filling the buckets is just a slam bang crash and upstairs with them.

The material Im currently using is fairly well ground up and more dense than my favorite stuff.

Normally the shells have more larger pieces and is a little looser (less weight by volume)



The next time I do a cleaning on the Advantage, I am going to run the stove auger and see how much it actually feeds in say 30 seconds, then do the math and figure out the pounds per hour.

The ground up shells are going to feed differently than the pellets do.

Seems like we all have a system down that works well though.

The folks that live where it gets reeeeeeeeeeeeeeeeeeeealy cold are going to have a different set of rules for sure.

Here in North west Oregon (25 miles south of Portland) the winters are not terribly cold but we can see single digits from time to time in December, January.

Mostly its windy, mid 30's to mid 40's and WET.

35F with a stiff breeze make it very nasty.


Snowy