Oil vs. Electric

Factual Questions
1

For the story of what happened, see this thread: My Oil Furnace Died - Factual Questions - Straight Dope Message Board

But this thread is about Oil vs. Electric. Well, Oil vs. Electric/ coal.

The house is not insulated as is. But I am in the process if insulating it. But the way the house is bult, there are no studs in the outside walls. So I am studing out the inside of the outside walls with half 2x4’s and insulating it with foam insulation rated to around R9 (the house is too small to use full 2x4’s. It would make the rooms too small).

I have tried looking online for information, but I can’t seem to find what I am looking for.

Would I be better off in the long run to buy a new oil furnace? Or to use electric baseboard heaters and get a hotwater heater? I know electric is expensive and is going to go up. But so is oil. And I will have the chimney in the cellar freed up, and I can get a coal burner for either nothing, or cheep. I could use the coal as main heat in the winter, and use the electric in rooms the coal dosn’t really heat as well as if I am too lazy to buld the fire up.

Any thoughts or ideas are a big help. Thank you.

2

You might want to look at the Energy Star website that the govt has. What you want to know is the “cost per BTU”. To make sense of the data you should check with your electric company - what do they charge per kilowatt? Check with your oil company - what do they charge per gallon? Then you can compare apples to apples.

Generally speaking - electric heating is by far the worst choice. Generally speaking - oil heat or propane are quite close in terms of cost. Generally speaking - natural gas (if it’s available in your area - is the most economical.

R-9 isn’t going to help you much. Depending on where you are, a lot of your money is going to heat the outdoors.

3

Electric is usually the poor choice but it has some things going for it.The heaters themselves are cheap and can be found at yard sales,surplus sales,etc.They are 100% efficient.They are easy to install.So if you’re having a cash flow problem they could be a stop gap measure until you get what you want in place.

4

I do have the money to get a new furnace if I need to. But my thinking was that if I can use the coal as the main heat, and only use the electric heaters as needed, that it would work out to cost less in the long run.

And I will need to check into natural Gas. I don’t think its in my area though.
Thank you all

5

[QUOTE=Fir na tine]
You might want to look at the Energy Star website that the govt has. What you want to know is the “cost per BTU”. To make sense of the data you should check with your electric company - what do they charge per kilowatt? Check with your oil company - what do they charge per gallon? Then you can compare apples to apples.

Generally speaking - electric heating is by far the worst choice. Generally speaking - oil heat or propane are quite close in terms of cost. Generally speaking - natural gas (if it’s available in your area - is the most economical.

R-9 isn’t going to help you much. Depending on where you are, a lot of your money is going to heat the outdoors.
[/QUOTE]

I would disagree with this. Historically, electric was more expensive than other energy sources. This is no longer universally true.

The most sensible approach, IMV, is to evaluate the various energy sources based on the real world costs [per unit] in The Man In Black’s area.

We routinely calculate energy costs for our customers (expressed in “cost per million Btus”) and LP was about the same as electric; with oil not that far behind. Natural gas was cheaper then LP/electric or oil. However heat pumps blow them all away.

This is a paradigm shift for HVAC contractors, but a hybrid heat pump/electric, heat pump/LP or heat pump/NG will provide the lowest utility bills.

6

[QUOTE=the raindog]
I would disagree with this. Historically, electric was more expensive than other energy sources. This is no longer universally true.

The most sensible approach, IMV, is to evaluate the various energy sources based on the real world costs [per unit] in The Man In Black’s area.

We routinely calculate energy costs for our customers (expressed in “cost per million Btus”) and LP was about the same as electric; with oil not that far behind. Natural gas was cheaper then LP/electric or oil. However heat pumps blow them all away.

This is a paradigm shift for HVAC contractors, but a hybrid heat pump/electric, heat pump/LP or heat pump/NG will provide the lowest utility bills.
[/QUOTE]

Thank you again. And since you are a contractor would you happen to know the rough prices of a heat pump and an oil furance? I have tried to look up prices on line, but hanvn’t had any luck. Just a ball park guess will do. $5,000? $10,000?
And if it makes any difference. It is a very small house. It is 2 floors and only 900 squar ft. total.
Thank you

7

You should definitely explore the energy star web site: http://www.energystar.gov/.
If you’re redoing the exterior walls there’s a lot you can do, such as a vapor barrier: http://www.doityourself.com/stry/vaporbarriers.
I’d vote for the heat pump, but it depends on several things, like ductwork, low temp. range in your area, electricity cost, etc.

8

Raindog,
Since you’re in the biz,could you answer and comment on some conceptions I have,which may be informing to the OP as well as myself.
I’m in the Northeast U.S. in an area that usually doesn’t get colder than mid-20s (F) but with exceptions into single digits.Summers are hot & humid,highs mid-90s.
I built my house to heat with wood. But my wife wanted A/C,so a heat pump was installed,and I fashioned a return plenum over the woodstove.This on advice regarding ability of subsequent homebuyer to obtain a mortgage.
Conventional wisdom at the time (mid-90s) was that heat pumps are not efficient below 35F,is that still true?
Is the back-up resistance heating bank an essential component of the device ?
Does the relative humidity have an effect on heat extraction at the low end ( assuming the 35F stated above )?
Heat pumps seem rare north of the Mason-Dixon line.

9

[QUOTE=The Man In Black]
Thank you again. And since you are a contractor would you happen to know the rough prices of a heat pump and an oil furance? I have tried to look up prices on line, but hanvn’t had any luck. Just a ball park guess will do. $5,000? $10,000?
And if it makes any difference. It is a very small house. It is 2 floors and only 900 squar ft. total.
Thank you
[/QUOTE]

At 900 ft, you [probably] need a 1 1/2 to 2 ton system at most on the cooling side, and 50-65,000 Btus for heat. (keep in mind, those are generalities—nothing more----based on square footage)

For reference, I just installed a 4 ton 14 seer heat pump, 115K Btus 95% efficient furnace converted to LP, a new humidifier, high quality 4" Honeywell pleated media filter and Honeywell 9000 IAQ thermostat (high end stat) for $8200.

Prices vary wildly. A fly by nighter, or moonlighter may be much cheaper. Or…a contractor may sell a cheaper brand of furnace. Region by region of the country may vary wildly.

That being said, in my neck of the woods a 2 ton HP, with a 60K Btu furnace 80 % efficient, with good stat, filter, duct start up, warranty etc would run between $5000 and $8000. You may find a good contractor who will do a fine job on the lower end of the scale. (Keep in mind, you may be an area where prices are lower too) In my area, if a price got a whole lot less than $5000 I’d worry about them, or what they’re putting in my house.

If you (or anyone) wants my 2 cents, you may PM me and I will talk via the phone to help evaluate proposals or answer questions.

10

[QUOTE=Carson O’Genic]
Raindog,
Since you’re in the biz,could you answer and comment on some conceptions I have,which may be informing to the OP as well as myself.
I’m in the Northeast U.S. in an area that usually doesn’t get colder than mid-20s (F) but with exceptions into single digits.Summers are hot & humid,highs mid-90s.
I built my house to heat with wood. But my wife wanted A/C,so a heat pump was installed,and I fashioned a return plenum over the woodstove.This on advice regarding ability of subsequent homebuyer to obtain a mortgage.
Conventional wisdom at the time (mid-90s) was that heat pumps are not efficient below 35F,is that still true?
Is the back-up resistance heating bank an essential component of the device ?
Does the relative humidity have an effect on heat extraction at the low end ( assuming the 35F stated above )?
Heat pumps seem rare north of the Mason-Dixon line.
[/QUOTE]

It’s been awhile since I fooled w/ HVAC, but I believe the temp. is a bit lower, around 20-25F. Heat pumps have an electric backup heater to kick in below that, which is much less efficient. If you live in and area where there are frequent temps. below that a heat pump is probably not for you, but if it only drops that low on ocassion, a heat pump is still viable.
I’m sure Raindog can be more specific.

11

[QUOTE=Carson O’Genic]
Raindog,
Since you’re in the biz,could you answer and comment on some conceptions I have,which may be informing to the OP as well as myself.
I’m in the Northeast U.S. in an area that usually doesn’t get colder than mid-20s (F) but with exceptions into single digits.Summers are hot & humid,highs mid-90s.
I built my house to heat with wood. But my wife wanted A/C,so a heat pump was installed,and I fashioned a return plenum over the woodstove.This on advice regarding ability of subsequent homebuyer to obtain a mortgage.
Conventional wisdom at the time (mid-90s) was that heat pumps are not efficient below 35F,is that still true?
[/quote]

While true at one time, it is no longer true. Of course, it is true that the warmer the climate the better the environment for a heat pump. So…you’re much more likely to see a heat pump in Atlanta vs Chicago.

Still, heat pumps will produce a million Btus (even at 20 degrees outside) cheaper than natural gas. However, as it gets colder and colder outside there is less heat in the air. Logically, this means that a heat pump becomes less efficient as it gets colder outside. The manufacturers have developed something called “co-efficient of performance” (COP) which tracks how many Btus a heat pump will “capture” at different temperatures.

For example, a particular heat pump may produce 50K Btus…*at 35 degrees outside. * At 15 degrees outside, it may produce 30K Btus. (just throwing out numbers—no real world comparison)

Now I’d be willing to bet that even at 10 degrees the heat pump will produce those 30K Btus cheaper that natural gas. The problem is this: As it got colder and colder outside----and the heat pump produced less heat-----your heating needs increased; you’re losing heat to the environment.

So the problem is not that a heat pump is economically inefficient. At some point, it becomes [as it gets colder] operationally inefficient. In other words, it’s still producing Btus (per Btu) cheaper than Oil/Elec/LP/NG, but it’s not producing enough of them.

Hence the need for help; for “back up” or “auxiliary” heat.

For the reasons above (and I hope they made sense), yes.

Not really.

True. But heat pumps have come a long way, and with other energy prices soaring they are seeing a big surge. The weather you desribe is similar to Ohio (it is 22 degrees right now in Dayton, Ohio) and we have tons of them here.

12

Or Google urethane insulation. Much more effective than fiberglass batts. Got a bad name many years ago with some shoddy fly-by-night operators. Seals better and provides a better vapor barrier.

Ideal for retrofits or reduced stud area/volume like you’re facing.

IANAUC but I used on a number of renovations of older homes (turn of the century homes, I guess I should specify 19th to 20th century) in Upstate New York a few years back. Even without window changes (people are usually stunned at the cost of new windows), heat bills dropped to level of new energy efficient construction nearby. And no drafts.

13

Raindog,thanks for your understandable reply,but one clarification needed.Is the back-up resistance a requirement to thaw the unit (which I thought was accomplished via reversing valve ),or simply to prevent homeowner’s butt from freezing?

14

[QUOTE=Carson O’Genic]
Raindog,thanks for your understandable reply,but one clarification needed.Is the back-up resistance a requirement to thaw the unit (which I thought was accomplished via reversing valve ),or simply to prevent homeowner’s butt from freezing?
[/QUOTE]

The homeowners butt from freezing.

A heat pump will freeze up (the outdoor unit; not the indoor unit) from time to time in the winter. This is natural. There is a defrost process, but it is unrelated to the electric back up heat.

The electric back up heat is there solely to provide comfort. The reason (as explained above) is that at some point the heat pump puts out less heat (due to less available heat outside as the temp falls) and needs “help”, which is often called “suplemental”, “auxiliary”, “back up” or “emergency” heat. (interchangeable terms)

I would point out that electric is the most common form of back up heat, but you may use electric, oil, LP or NG as back up.

15

Once upon a time I lived in a moderate clime (Central Virginia) in an uninsulated house with electric baseboard heating. Let me tell you some of the problems.

  1. The baseboard is lying flush against something cold – ie an uninsulated wall. I can’t prove it but I am certain this equals wasted energy heating “the great outdoors.”
  2. The heat is completely passive and lacks any push other than convection. It takes a long time to get a room warm if its larger than 12x12
  3. In order for the whole house to be warm, you must turn on every baseboard heater. Conversely, if you only want to heat the room you’re in, when you’re in it, you have to find someway of sealing off, say, your living room from your kitchen. As open-plan homes are more the norm these days, this can be a challenged (I bought heavy drapes and hung them over my doorways.)
  4. In order to work, it has to be in a spot that allows air to circulate over it. In other words, you can’t put a TV, bookcase or other large furnishing against a wall with a baseboard without impairing its heating ability. Your baseboard tends to determine they layout of your room in other words.
  5. Its a fire/melting hazard. One time I left my Rubbermaid hard plastic laundry basket too near the baseboard and it melted. You have to be careful to keep cloth and other flammables away from it.

Anything good about it? No, not really. Without doubt it is the worst and most expensive heating system I have ever lived with (includes: central heat, steam generating furnace, woodfire)

Just my own personal observations.

16

Thanks to Raindog and everyone for the help. I still have a lot to think about.

And I live in north east PA. So it can get into the single digits, and colder at times.

17

Raindog,thanks again.I burn wood below 30F and use the air handler to distribute heat gathered in the above mentioned plenum.There is a cut-out in it so the heat pump doesn’t kick in.Unnecessary really,if I’m not careful the house gets in the upper 70s.
The back-up heater has a 100amp breaker,why I try to avoid its use and revving the meter.

18

[QUOTE=smithsb]
http://www.foam-tech.com/products/urethane_foam/foam_properties.htm

Or Google urethane insulation. Much more effective than fiberglass batts. Got a bad name many years ago with some shoddy fly-by-night operators. Seals better and provides a better vapor barrier.

Ideal for retrofits or reduced stud area/volume like you’re facing.

IANAUC but I used on a number of renovations of older homes (turn of the century homes, I guess I should specify 19th to 20th century) in Upstate New York a few years back. Even without window changes (people are usually stunned at the cost of new windows), heat bills dropped to level of new energy efficient construction nearby. And no drafts.
[/QUOTE]

I started reading up on this. But I see a few downsides. One is that this site: http://www.eere.energy.gov/consumer/your_home/insulation_airsealing/index.cfm/mytopic=11600
says that the R value of Polyurethane Insulation can drop by as much as 2 points from there example.

Another is that this company in my general area: http://www.pasprayfoam.com/Pa-Spray-Foam-inside-walls.html
Seems to say that 1" thick on foam will be R-6.5. The thickest I can go is 1.5" (just under really) on my walls. So that would be around R-9.75, which is almost the same as the R-9 hard foam I found.

Now I understand that Polyurethane dosn’t loose much of its R value in wind, like other Insulation does. The house layers from outside in are: vinyl siding, thin (1/4" or 1/8") Insulation, the old brick-tex siding (they just left it on), 1/4" wood sheets (I think), then the planks of the house. Is the R value really going to go down much because of wind here?

And last, I read that you need to use 1/2" sheetrock with it. I was not planning on useing sheetrock.
So with Polyurethane loosing R value over time, and it being about the same R value as the hard foam anyway, is it really better? Would it be cheeper?

Thank you.

19

So what would a heat pump system cost for a 900 sqft home?

20

[QUOTE=Saint Cad]
So what would a heat pump system cost for a 900 sqft home?
[/QUOTE]

Where do you live?

What type of fuel are you using right now for back up?

What type of fuel would you be using in the future for back up?

Is there an existing A/C system?

Do you need new ductwork?