# Furnace vs. Gas Stove Dabate



## premington (Jul 28, 2011)

Hey Kids! First time poster...

I'm having a friendly debate with a buddy of mine and wanted to get your take on this issue.

I'm buying a Lexington Forge Concorde CSDV40 38,000 BTU gas stove to zone heat my home rather than run my furnace all the time. I have a ~100,000 BTU furnace that heats our 1,700 sq. ft. home and we're only really in the main living space most of the day--half the home is unoccupied during the day. It's a raised ranch, so what we want to do is install the stove in the lower level, directly below the main living space. We'll use a remote thermostat to control the stove's cycle times and set the stove for a temp in the lower level that will maintain a comfortable heat in the upper level.

The debate is whether this will be effective and a cost savings. He feels the stove and furnace are about the same efficiency and I'm still using gas, so the actual gas costs will be identical (we agree on this, of course). The blower on the furnace is nominal in terms of electric cost (we agree on this also). Where we disagree is on the concept of practicing zoned heat. My thought is to concentrate the 38,000 BTU heat only on the 800 sq. ft. area that we're living in and ignore the rest of the house. The stove would be in about 350 sq. ft. of space in the lower level and there's about 450 sq. ft. of space in the upper level directly above it. I'm hoping the heat will rise from the lower level and heat the upper level. I plan to experiment and make adjustments, as needed. For example, install registers around the lower level that channel the heat to flow up to the upper floor, or use a fan to push air into the stairwell. I have a ceiling fan above the stairs that can help pull the air up and distribute it around the upper level.  The stairwell leads directly into the lower level where the stove will be.

My neighbor has the exact same house as me (a little smaller) and does exactly this, but with a wood stove. She said she doesn't have to do anything special... The heat radiates through the floor and heats the entire upstairs. Her gas and electric bills average about $140/mo in the winter and she spends about $500 a year on wood (total cost is about $225/mo). Mine is about $340/mo! We live in NY where we have very frigid and long winters.

I'm curious to hear others thoughts... Hopefully from those who are currently using a gas stove perhaps for similar reasons. Do you find it a cost savings? Is my friend right and perhaps I won't see really any savings? What do you think?

-Paul


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## DAKSY (Jul 29, 2011)

Zone heating is the way to go. Heat the areas you use ONLY when you use them. 
Simple math says you'll use approximately 40% the fuel so you SHOULD
realize a savings. You're are probably incorrect, however, in assuming the 
efficiencies are the same. They probably aren't - especially if the stove is 
adjusted for ambiance. The display of a realistic looking, yellow flame is 
where the efficiency is lost. If you tweak the ATF ratio to get a bluer flame,
your stove will burn the fuel more cleanly. Clean = efficient. 
It just won't look like a real wood fire...
Also, you need to figure out a way to get the cold air from upstairs to return to the
basement, or you probably will not get the heated air to move up. 
The standard way to do this is to cut convection vents thru the floor - near
the outside walls - to allow for the cold air returns.
You may want to check your local building department to see if this is a code violation 
In many areas it is, as it essentially eliminates a fire stop between floors...
HTH...


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## Fake coal burner (Aug 1, 2011)

How well is the house insulated windows etc. wood stoves burn hotter than gas. I think you will not get the heat to the room you are using to be comfortable unlees you are running gas stove on high most of the time. Then you gas usage is going up. I am using a gas stove in the living room on low after 4 hours on high to heat room to 78deg. space is 450 sq ft. The rest of the house is around 60 deg. day temp. with a vent above door  forced  cold air returns to stove that  I made. The house is 11000 sq. feet 8 foot ciealings bungalow house. Open doors to the rest of the house stove goes to high all the time. The rest of the house is about 65 deg. Living room drops to around 68 deg.Stove is  22,500 btu on high low is 8.100 btu On low I save about 1/3 on my gas bill. I use the 80,000 btu furnace about 5 hours a night to keep water pipes from freezing in the .basement


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## iceman (Aug 1, 2011)

340 a month seems kinda high for gas .. is it propane?
I would start with the house itself.... Check your insulation you Prolly need to add more. 
What type of heating system do you have?
I would put the stove in the area we use the most. If you spend most of it upstairs, put it up there and put a thermostat downstairs
The purpose of zone is to heat where you are in order to cut it back in other places. If you put it in the basement and have to push it hard you might as well whn furnace .. if you put it upstairs and keep it on low there is your savings.


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## premington (Aug 1, 2011)

*Iceman:* Perhaps I should clarify. Yes, $340 for gas and electric is high in the winter for a home like mine. This past year I put on a new roof and also blew in ~36" of insulation. The old roof had no venting at all and only six inches of R-19 insulation, which is _horrible_ for a home in a Zone 5 region. Since making this change, I've seen a *world* of difference in heating and cooling!  Hopefully this will enhance the quality of outcome using a gas stove.

*Fake Coal Burner:* My windows aren't the greatest, but not bad. They're double-paned windows that are starting to get a little tired, but still have life left in them. You may be right about having to keep the stove on high all the time. I'm going to have to experiment to see how to manage the heat. As I said, my two neighbors have wood burning stoves that do a great job, but, as you pointed out, wood burning stoves generate a lot more heat. I don't know the BTU rating of their stoves and I'm not sure how 38,000 BTUs will settle in my home.

Keep in mind, half my downstairs is below grade (raised ranch). The walls are a finished six-course block, then it goes to exterior walls. I'll do direct vent out this wall above the blocks. The lower level of the house is always much cooler than upstairs, so we want the stove there to keep the downstairs nice and warm during the winter. We're really hoping heat will rise to the upstairs naturally, as it does for our neighbors. The downstairs has an open doorway that spills out into the stairwell to the upstairs and we hope the heat will naturally rise up this stairwell. We'll turn on the ceiling fan and hope it will draw up the heat and perhaps put a fan down there to blow the heat out of that lower level and into the stairwell, where it should naturally rise.  The top of this stairwell is our main living space.

*DAKSY:* Thank you so much for mentioning that it might be a code violation to cut vent holes in the floor to draw-up heat from the lower level. I never even considered that! Today I filed for a permit to install the stove and will make a note to ask the inspector when he arrives if this is allowed. You may be right about the stove being a tad less efficient than the furnace. It was my understanding that the stove manufacturer takes into consideration the quality of combustion being used (yellow flame vs. blue flame) and this is part of the 80% rating given to the stove. I could be wrong. Either way, I know my furnace is between 80% and 85% efficient, which is more than the stove's 80% rating. Still, we're concentrating the heat energy to a confined portion of the house. I suppose we could find that keeping the house warm by cycling the furnace is cheaper than keeping the main living areas warm by running the stove. My friend feels this will be the case. I'm betting that he's wrong. Of course, I could be the one who is wrong.  

That's why I was hoping to get comments from people here. I was curious what the majority consensus was with all of you.

-Paul


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## iceman (Aug 2, 2011)

340 for gas and electric isn't bad... 
You ever consider wood or wood pellets?


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## premington (Aug 2, 2011)

Well, $340 a month is average around here for people with average 1970s homes, which typically had inadequate insulation when built.  Properly done, I should be in the ~$250 or so range.  Also, remember, that's averaged. Some months we've been well over $500 a month while others (in the summer) we're in the $150 or so.  $340 a month is before we had the new roof done with proper venting and another 36" of insulation in the attic.  That should have a noticable impact on our heating bills this winter.

Yeah, I did look very seriously at pellet stoves.  I loved them and almost sprang for one, but what held me back was the inability to use it in a power outtage and the extra maintenance and mechanical parts, which are prone to eventual failure in time.  Right now we have a gas stove in the kitchen, a gas water heater, and (soon) a gas stove heating appliance in the lower level.  We're good for meals, showers, and (soon) comfort with no power at all.  Also, gas is so little maintenance and much cleaner (no smoke or dust or ash), with a pregnant native-Chinese wife (Chinese wives are clean freaks), it was a decision she was very much in favor of.

I really labored over which to choose... I really, really liked the pellet stove and struggled with the decision.  There are a lot of positives to choosing one, but in the end, the ability to have heat with no power won out.  We've had two ice storms here that knocked out power for many for a week on both occasions.  It was a major inconvenience.  I know... A generator would provide the power I need to run the pellet stove, but that's another expense.  With a baby on the way, we have to pick and choose our financial battles. 

Love reading this forum and appreciate the replies!

-Paul


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## Fake coal burner (Aug 2, 2011)

I would be moving if my gas and electric was $250.00
Mine was $210 . for the coldest mouth January 2011 for all NG. gas, water, electric, sewer every  thing is gas cook stove, owen. water heater gas heat stove gas 80,000 btu furance Single pane windows ever 5 feet apart double brick walls 18 inches blown in isolation attic. zone 5 cold. If you have to buy wood I dont think you would save any thing That is why I took wood stove out.


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## premington (Dec 9, 2011)

Well... It's been a while since this discussion was last discussed, but since I now have the gas stove fully installed and we know how well it's working, I thought I'd post an update.  Perhaps someone can learn from our experience.

As a reminder for those who forgot about what this is about, so you donâ€™t have to read older posts, Iâ€™m referring to the installation of a 40,000 BTU Lexington Forge (CSDV40) gas stove to be used in place of the 80,000 BTU furnace.  The idea is to zone heat only the areas of the house we use during the day rather than use the furnace to heat the entire house.  Will this be a savings over using the furnace?

It turns out the gas stove is definitely cheaper than running the furnace for a number of reasons.  We installed the stove in the lower level of the house (raised ranch).  The heat wicks out of the lower level room and into the stairwell leading up.  The stairwell acts like a chimney, in a way.  The heat pulls out and a ceiling fan at the top of the stairs spreads the heat around the upper level.  We've noticed this wicking action pulls colder air into the room from lower to the ground.  So the heat stays tight to the ceiling while about three feet off the ground you can feel a current of cooler air.  For this, we installed a folding door at the entrance to the lower level.  When we're down there, we close the door.  This locks the heat in and stops the current of cool air.  A thermostatic control turns the stove on and off and maintains the temperature at any temperature we set.

As for the zoned heating discussion, the door enables us to block off the rest of the house and sleep downstairs without having heat spill out to other areas of the house.  When we want to heat the upper level, we open the folding door and heat easily wicks out and up the stairwell.  It works great!  But it only heats either the lower level or the upper level on one far end of the house.  Go down the hall of the upper level and it's *cold*  But we don't use that part of the house much during the day.  When we go to bed upstairs, we use a small space heater in the bedroom and turn off the stove.

As for costs, I have numbers.  Last year the average temperature for November was 43f; this year it was 45f.  Gas and electric costs for last year were $260 for November 2010.  Gas and electric costs for November of 2011 were $116.  Impressive!

Now, keep in mind I did more upgrades than just the stove and this is adding to the savings, I'm sure.  I added about 12" of additional insulation in the attic.  But, even still, I'm certain that using the 40,000 BTU stove (32,000 BTU on low) instead of the 80,000 BTU furnace is providing a nice savings.

BTW: The entire cost for the stove was $1,100, vent kit about $200, gas line about $100.  Did the install myself with a few friends (and the town code inspector) and for $1,400, it was an awesome upgrade!

Curious to hear any similar stories from others who may have installed a stove and are heating their home using it instead of their furnace.

Cheers Brothers and Others! 

-Paul


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## eclecticcottage (Dec 9, 2011)

We heat our old house with two DV gas stoves-a Lopi Heritage Bay (the smaller discontinued model) downstairs with a blower and ceiling fan to circulate the air, and a Lopi Berkshire upstairs with just a ceiling fan.  The house never had central heat, it had a gravity heater when we bought it and that thing scared the bejeebers out of me, I kept thinking one of the pets would knock something flammable into it and we'd have a fire.  the gravity heater had a big advantage-because it was in the floor, it kept the crawl space warm and we didn't have to leave the water running a bit to keep from freezing the pipes and it actually cost us less to use in gas/electric (since it didn't use electric).  The stoves look better though.  We went with a Lopi republic wood burner and a Procom (still to be installed) VF fireplace in the cottage (will be our house when we're done with renos).  So far seems these will cost us less to run than the DV stoves, but still better than trying to replumb all the radient heat lines and get a new boiler (blown lines due to freeze damage and who knows what might have happened to the boiler, which was an early 80's model repco).


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## firecracker_77 (Dec 10, 2011)

I essentially do the same thing.  We have a little Woodstock Gas stove in the basement which is 1/2 the size of our raised ranch.  I heat the basement when we are downstairs and leave the stair door open with the furnace set low to where it doesn't run.  I'm sure the heat rises, but it doesn't really heat the upstairs to a comfortable setting.  However, the area we are hanging out in where we watch movies in the basement gets very warm.  I don't know about energy savings, but it probably costs less.  The bigger thing is for us.  We would have to crank the hell out of our furnace to get this naturally cool area anywhere near that temperature, so by that we have to be using less gas.  We have a 92% H.E. furnace, so our costs aren't ever too high, but it's a matter of being really warm versus the whole house being an average temp and the basement tending to be much cooler.  If you try those vents like some suggested, it will surely help raise the temps upstairs.  My stove is 22,000 BTU and yours is almost double that output.  I'm sure that will make a big difference.


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