Electricity Savings of Operating Wood Stove vs Forced Air Electric/Heat Pump

[pyper]

Heat pumps are also more efficient if you leave the thermostat alone, or adjust it in small increments. With the one we have (and they can be different) the "emergency" heat comes on any time the thermostat differential is 2F. Emergency means the whole system is a giant space heater, which uses twice as much (or so) electric.

I have no idea how much electric we save using the stove. This year we have used the heatpump only two or three times. I like the heat from the stove. It feels warm. The heatpump never really made anything feel warm.

 

[maverick06]

We have a heat pump with oil fired "emergency". Its hard to truely identify the amount of energy savings. I use 30g of oil a year, the power bill goes up about $30/month relative to no ac/heat pump, and I burn about 2-3 cords a year.

If the temp is ~45F or up, I will let the heat pump take over, below that, I will run the fireplace. Since I buy my wood, I think about 45F is turning point.

I would recommend the heat pump to anyone, it saves a lot of money.

 

[Renovation]

We have a heat pump with oil fired "emergency". Its hard to truely identify the amount of energy savings. I use 30g of oil a year, the power bill goes up about $30/month relative to no ac/heat pump, and I burn about 2-3 cords a year.

If the temp is ~45F or up, I will let the heat pump take over, below that, I will run the fireplace. Since I buy my wood, I think about 45F is turning point.

I would recommend the heat pump to anyone, it saves a lot of money.

Thanks for the info.

No NG where I am, so, before I discovered new-fangled wood stoves, I put in the heat pump, planning to bite the bullet and burn propane during coldest weather. That was serendipitous, because I think the heat pump is a good compliment to wood stoves. I think mine's efficiency limit is about 32 degrees.

 

[micaaronfl]

i know this is an old thread but very interesting. i have a heat pump and i live in PA. the pump is about 22 years old.

im looking for ways to improve the use of my stove so i do not have to rely on the warmish heat from the heat pump. the house is about 4k sq ft colonial style with a closd floorplan. the stove sits in the family room. so far i have cut out vents into the transom peices down the one hallway, but not the second hallways as its a support beam. on the lower levels of the house i have also installed thermal curtains.

i usually keep the house temp at 67 as i believe anything more than that will kick the emergency heat on. anyone else with heat pumps have any other suggestions, thermostats etc...

 

[warmhouse2]

I have 2 Heat pumps that are about 10 yrs old we pay about .17 kwh and my bill last month was $575.00. Oh yeah we also have solar panels that saved us about $200 last month. We are hoping our new pellet stove will lower our electric bill this month. Time will tell. Before the pellet stove house was heated to a chilly 64*. It is now a WARM 78*

 

[BrotherBart]

I have 2 Heat pumps that are about 10 yrs old we pay about .17 kwh and my bill last month was $575.00. Oh yeah we also have solar panels that saved us about $200 last month. We are hoping our new pellet stove will lower our electric bill this month. Time will tell. Before the pellet stove house was heated to a chilly 64*. It is now a WARM 78*

What is your electric bill when you aren't heating?

 

[micaaronfl]

575 are u kidding me im heating a 4000 sq ft house ( at 73 degrees all day with an electric heat pump and a wood stove and im paying 220.00 in philadelphia. you need to find a new suppliers or buy another house.

 

[maverick06]

My suggestion for heat pump use is do what I do.

If it is "warm" outside (I discribe that as 45F+) or if you only need a little heat in the house use the heat pump.

The wood stove does most of the heating, the heatpump takes over when you are away or on the shoulder season.

 

[Lumber-Jack]

NYSEG in NY used to offer a "fixed" plan and a "variable" plan, now starting in 2011 only the "variable" rate plan is available. Power cost goes up and down with demand. I can't speak for Virginia since I don't live there, but it doesn't sound like the same type of pricing applies there.

Heat pumps have certainly improved over the years, but there are still plenty out there with efficiency that is lacking at <40 degrees F. The single SEER or HSPF number doesn't really tell much - you have to look at the coefficient of performance (COP) vs. temperature curve. Mine dropped well below 2 at 30 degrees or less, and anything much below 2 means a lot of <80 degree air being blown through the ductwork - not a very pleasant heating method.

But the biggest beef I have with heat pumps is that most people don't understand how they work, and most people treat them like a fossil fuel heating appliance. When the thermostat is rapidly turned up, the electric resistance heating backup is turned on and that completely negates any efficiency advantage of the heat pump. Maybe newer units don't operate this way, which would be a big advantage.

My heat pump is going on 3 years old now, it was installed with one of those programmable thermostats and the default setting was as you described where the electric resistance heating backup is turned on when there is a large differential in the temperature setting and ambient temperature, but I figured out how to reprogram it so it only uses the heat pump for heating and the electric resistance will not kick in at all. Of course it takes longer for the house to heat up in this mode, but what the heck, I never use the heat pump anyway, my wood stove does a fine job of heating the house. The heat pump works well for cooling the house down in the middle of the summer though, a task that the wood stove fails miserably at.

 

[warmhouse2]

Spring and fall (no ac) with the solar about $75.00. in the summer with ac on temp about 74* 200 - 250 per month. NOTE the bill for 575 was BEFORE the pellet stove that was with our heat from the heat pumps.

 

[Hankjones]

When I run my insert I use about .7kw/h for my 1200 sqft house (home inspector said it was very well insulated). When the heat pump kicks in, it's usually around 4kw/h. If it's under 20f the heat pump never stops, seems to run at 4 to 5kw/h. I was hoping to save more with my wood insert, but this morning it was 16F outside and my heat pump was putting out 85F out of the registers with 4kw/h. That seemed enough to not have the backup electric coils turn on. I thought it would cost a lot more to run that heat pump with under 30f weather, but maybe not for me. My heat pump maybe oversized, it's a 20yr old trane xl1200.

Note: it's rare the heat pump runs non stop, usually with 28 to 35f weather it cycles on and off and i use about 2 to 3kw/h more then with my wood stove. Did all the calculations, burning wood still doesn't make financial sense for me... To late to change my mind so it's a lifestyle thing.

 

[warmhouse2]

to HANKJONES thanks for your infomation I know our HP units need replacing as they basically run full time when its 30 or below outside the heat from the registers is barely warmer than the room temp which at the time before wood pellet stove house only heated to a max of 64* so therefore the heater was barely throwing air warmer than room temp.

Thanks for all the info.

 

[seeyal8r]

I live in north central oklahoma. wind averages 20 mph but gusts can get up to 50 so our lows in the 20's to upper teens are very cold and our highs in the summer are usually around 105. I have a swimming pool and my wife and kids use electricity since they are at the house constantly. Our highest electric bill in the summer was $285 cooling the house to 76 degrees and last winter was $260 while heating the house to 65 degrees. We installed a fire place insert to take advantage of the abundance of oak in our area. Just got decembers bill.... $76. January is the most expensive heating month usually but I anticipate it to be around $90 since we've had to kick the heater on some mornings when the fire has burned down. Best part is we keep the house between 68 and 75 degrees this winter.

 

[Boozie]

I just got my electric bill for 12/13/10 to 01/14/11. My insert wasn't installed until 12/17 and I don't burn all the time. My bill was $95 less than the same time period for 12/11/09 to 01/12/10 with the same average temperature. I'm happy.

 

[BucksCounty]

I am in Philly suburb with PECO and have a heat pump from 93. We just moved in and I have been burnign so I really don't have a true comparison WITHOUT burning. I know it is helping though. Our December bill was 275. Wife does complain the bedrooms are cold and I have made some vents trying to move the heat. It is a 3300sq. ft. home, which includes a 500 sq. ft. addition with no heat (using Shelburne in that room and it is toasty) . Stoves used are in sig. We are considered "preferred" customers so after the 1st 600 kilowatts, the cost per kilowatt is cut almost in half. .15 cents first 600 kw and then .077 cents after. Problem is the discount with PECO is gone after 2011. I am searching for a stove to replace insert as main source in main part of the house.

 

[warmhouse2]

Thank you for everyones input it looks like the Pellet stove is lowering our electric bill even though the stove uses electric 24/7

From Dec 8 to Jan 10 our total KWH 3138, solar credit of 112kwh we were billed for 3026 kwh

From Jan 11 to 1/24 our KWH usage so far is 978 with solar credit of 45 for a billed usage of 933.

Thanks everyone.

 

[maverick06]

hank interesting! I would suggest some calculations based on $/btu delivered. I ran the math on mine, and figured it will always be cheaper to heat with wood, until you hit the point where a firebox full of wood puts out more than BTU/hr than you need.

But it all is effected by the efficiency of your wood stove and your poirtion of the country (as modified by the temperature band you let it run) coupled witht he price you pay for wood and electricity.

So its a seperate case for everyone.

I have a thread with the details of the math/thought process behind my work: https://www.hearth.com/talk/threads/69040/

Rick

 

[henkmeuzelaar]

Since we have just moved into a new rural loghome in Targhee NF, Idaho, I have a chance to design an entire new home heating system. As a lifelong pyromaniac with a passion for efficient, low emission energy conversion techniques I would love nothing better than to buy one of the newer, clean-burning wood stoves, if only I could justify the expense in terms of monthly operating costs......

Unfortunately, I am up against some harsh realities: our local hydroelectric power is supplied at a cost just below 5 cents per kWh. My calculations show that at at a local cost of minimally $ 170 per cord (delivered and stacked) and a NET combustion process efficiency around 55 % (i.e. jncluding expected moisture evaporation/heating, stack heat flow and OAK rewarming losses) the 20 million or so BTUs in that cord are going to cost me 17,000 / 20,000,000 x .55 = 1.545 cents per 1,000 BTU (or 3.2 x 1.455 = 4.95 cents per kWh equivalent).

So, until local electricity prices go up one day, it seems to me that we are best off to stay with the 7 or 8 thermostatted 1300-1500 W electric heaters (mostly of the fake fireplace type), distributed over the various rooms and open spaces, that were able to keep the house warm while we were finishing it before moving in. One of the most attractive aspects of this all electric, distributed system is that it easily ties in to a central, programmed temperature control system.

If you found yourself in my place and wanted to convince your wife (who happens to have a good head for dollars and cents) that it still made sense to get a nice big woodstove, e.g. for the basement, in spite of these rather depressing realities, how would you go about it?? I should mention that the living room already has a Majestic fireplace with glass doors and forced air circulation which has proved to provide a half decent back-up for power outages.

Henk

 

[begreen]

I can't disagree with the assessment. If the power looks to stay cheap hydro, resistance electric will work. I would switch to a 220v system, permanently wired. It will be safer and should be lower maintenance. The fireplace heaters may be cute, but they are no more efficient than a $25 electric heater of the same wattage and they cost a whole lot more. With a good sized wood stove for ambiance and power outage coverage, and that nice solar gain, you should be all set.

 

[henkmeuzelaar]

Thx10e6 for the expert assessment, BeGreen!

Agree about the electric fireplace heaters but I happen to be married and they do look pretty cute in the bedrooms....

(BTW, I found out that the cheaper electric "insert" type HomeDepot sells does a much better job imitating a real woodfire than the large, expensive mantel types available).

Henk

 

[warmhouse2]

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[Coleman Stove]

ColdNH-

Your 2009 usage was just alittle above mine now, what size home do you have?

Also it looks like you're at 52% and I'm at 45% less than '09

LLigitfa-

You are correct, no factor for wood expenses. It's a new lifestyle for me so far, I was just hoping for a little more ROI. Yes the whole backup is how we started with the stove.

Den/BB-

That's about what ours is total. Even using the total it's about $116/28 days or $4.14/day I called the power company to get a clarification of fixed and variable costs. The Basic Consumer Charge and Power and Energy Charge are fixed. Although the P&E charge fluctuates by the cost of their fuel cost, not my consumption. The variables are; Variable Distribution Charge, Level Purchase Power Facilities and taxes/surcharge.

----------------

So far I'd say if I had to purchase wood at any price it defintely wouldn't be worth it. Right now I'm burning around a cord per month, at variable electric costs my wood is $63/cord, total electric costs $116/cord. Not to mention my time and costs. I'm starting to think of the old Luskins cheapest guy in town commercials

I'm going to keep tracking this and try to nail down the variable costs and see if there are other things I'm missing.

God I really need to get into this sort of business because I would be saving myself hundreds according to your guys' numbers

 

[pgmr]

A heat pump generally doesn't work well in setback situations using a programmable thermostat. Because the recovery time is so long, most systems are setup to kick on the backup stage if the temp isn't rising fast enough or set point temp is X # of degrees above the actual temp. Using resistance coils, NG/propane furnace or oil to recover the temp is probably a wash with the $ saved during the setback period.

For those w/resistance coils, the COP for those is always 1 (100% eff - theoretically). The COP of a heat pump is always greater than 1 (it's not "making" heat, simply moving it from outside to inside). You should never set your system up to bypass the hp and only run the coils (unless the hp isn't working). Let the hp run, the coils are meant to supplement the hp and also to temper the air during a defrost cycle.

 

[billjustbill]

We've been in our 2,100 sq ft. home for 35 years... We use Propane for the hot water heater and Central forced air. The early years saw single pane to double pane vinyl windows installed. Original tongue and groove knotty pine boards were sealed when I installed real Birch paneling and finished with a hand rubbed stain and brush finish. The old Propane furnace has been replaced twice and upgraded efficency in those years. With additional insulation in the attic and blown into the walls, we have dropped our Propane usage by 2/3's, with the most change since we had the Lopi Freedom Bay installed in the fireplace.... From three 400 gallon tankfuls down to just under one tankful per year.

Wood has been sourced from fallen Oak and Pecan trees in a public park, so cost for it is only the sum of sharpening 3 or 4 chains and a couple of gallons of fuel mix and bar oil. The bar oil I buy is mixed with my old crankcase oil I catch when I have the cars' oil changed. Since I use "Duralube" as an oil additive, I mix 3 parts of bar oil to one part (quart) of old oil-change oil. The oil additive still fuctions and gives great lubing properties and life to the chains and bar.

Here in the Dallas/Ft. Worth area, I'm burning about 1-1/2 cords for my heating season, although, this year has been much warmer that the last 30 years.... The feel of a "full warmth" from wood heat flowing out the Lopi is more comforting than the Propane heat. When temps drop into the 20's and teens, the only minor problem I have is getting the heat down the hallway to the bedrooms. If it's 76 degrees in the den, kitchen and livingroom/dining room, it may be 66 degrees in the bedrooms. This year, Propane is about $2.50 a gallon, so heating with some "Free" seasoned Mesquite, and mostly Red Oak and Pecan is great. In reality, the total cost of at least a cord of wood is less than $45 a cord (gas, oil, 3 chains sharpened and two gallons of Tractor Supply Bar oil)... and my "free" labor.

Maybe this can help you and others readers to figure your Winter heating cost/savings:

http://www.travisindustries.com/CostOfHeating_WkSht.asp?P=4

 

[HotCoals]

A heat pump generally doesn't work well in setback situations using a programmable thermostat. Because the recovery time is so long, most systems are setup to kick on the backup stage if the temp isn't rising fast enough or set point temp is X # of degrees above the actual temp. Using resistance coils, NG/propane furnace or oil to recover the temp is probably a wash with the $ saved during the setback period.

For those w/resistance coils, the COP for those is always 1 (100% eff - theoretically). The COP of a heat pump is always greater than 1 (it's not "making" heat, simply moving it from outside to inside). You should never set your system up to bypass the hp and only run the coils (unless the hp isn't working). Let the hp run, the coils are meant to supplement the hp and also to temper the air during a defrost cycle.

So I should let my HP run even when it's way below 30F?
Only need back up if I'm gone a few days...then it's the heat pump and resistance forced air furnace.
In order for my coils to come on I have to actually lose temp when the HP is on..double mercury thermostat.