I have a house under contract that has a underground storage tank that is probably as old as the house. 20 years. I’m just beginning negotiation after getting my house inspection report.
The tank has to go. I don’t want another underground tank..so I’m thinking about my options and am interested in your opinions/expertise. The ground floor is bedrooms and a small utility room on a concrete slab. In the uility room a boiler supplies baseboard hot water heat and feeds the hot water for showers etc through a coil demand system. (or however you call it. ) There’s not a lot of room in that closet.
Questions:
1. Is it possible to convert this to propane?
2. As propane a good idea? My alternative is an outside tank that has to be kerosene. ( I live in the NorthEast.
3. What is it likely to cost ballpark?
4. The slab is likely to be cold in the winter – I was getting ready to have engineered wood floors installed.. Can I put radiant heat there instead fueled by the same boiler that does the upstairs baseboards?
5. Can I put the engineered wood over the tubing? Probably not – Since it needs clearance to run above the concrete and below the floor.
6. Is there a good product that would insulate the floor from the cold of the concrete?
Thanks for your thoughts..
Replies
riaamp,
Heating a boiler for hot water is very costly way to do it especially in the summer..
Costs are going to be all over the map and none of them cheap..
Don't count on answers from experianced people to steer you in the right direction.. Let me give you an example.
My own house, everybody knows that natural gas is cheaper than electeric heat for a water heater. But I did some carefull research and found that the cost per therm is the same with electric or gas.. Minnesota is near the western coal mines so we have three really efficent coal burning plants, two well run nuclear plants and recently coming on line are whole bunch of wind generators. (western Minnesota is a very windy place).. that means electrictricity is actually in abundance while natural gas is getting more expensive.. I can buy efficent electric water heaters much much cheaper than I can buy natural gas water heaters. Plus, natural gas requires a hole in the roof to let out the exhaust.. That's a 4 inch hole sucking out heated air 24/7/365. warm air rises which draws cold air in to replace it.. Thus anything with a vent is sucking out warm air and sucking in cold air.
So counter to common advice I selected electric water heaters.
That may or may not apply to you.. check your local costs..
"Don't count on answers from experianced people to steer you in the right direction"
It is much wiser to count on those with actual experience, than those without it. BTW, your energy decision was made on incomplete and/or inaccurate information and inappropriate assumptions.
"But I did some carefull research and found that the cost per therm is the same with electric or gas..."
Did your "very carefull" research also indicate to you, that even though the costs are nearly identical at the present, that the price of electricity in the upper midwest is artificcially depressed and due for a substantial "adjustment" in the near future (this is fact that can be verified reading any energy trade publication)? You read those while reseaching this right? Did your research also indicate to you that when any of the worldwide carbon reducing protocols get adopted in this country that the cheap coal produced electricity will disappear faster than you can say "see ya, GW". The price that you pay for electric power will double in the next 5-7 years. By then, those electric water heaters will become even cheaper.
And, I'm not even going to try (again) with educate you with the facts about your fictitious 4" hole.
Tim,
Electrical Costs in the upper midwest have been due for a revision now since the 1990's The simple fact is that our utlities are publicly owned and it requires more than simple market forces to change them..
However every single report I've read says that Natural gas is getting more expensive as well.. so if electric costs increase at worst they will increase with the increase in natural gas..
Remember We have efficently run nuclear powerplants, a greatly increasing ability to capture wind power, and we are the closest major neighbor to the western coal mines. By all reports we have enough coal to last over two hundred years.. (more than enough for me to research again in twenty years when it's going to be time to revisit energy usage)
I wonder why you feel that it was fiction that I had a 4 inch hole letting heat out 24/7/365 when I used natural gas to heat with?
Actually It was connected to a much larger flue pipe that had been used for the exhaust for the older furnace. (but the flue for the exhaust for the water heater was only 4 inch..)
That ignores the fact that the flame in the water heater requires oxygen which comes from conditioned air already in the house. Burning that air and sending it up the flue uses up air. It then creates a small vaccum which draws in outside air to replace it. If it's 20 below outside then 20 below air is sucked in.. now the furnace needs to warm up that air..
I will wholehardedly agree with you that we should adapt the Kyoto Accord. However I have not done enough research yet to decide if the use of natural gas is evenrionmentally better or worse than burning of coal.
On the surface it would seem obvious.. Coal makes this wicked black smoke when it's burned and natural gas leaves an almost clean smoke.. I'm not sure that the visable black smoke is really the problem.. Besides if I drive over to the powerplant that is burning coal I don't see any visable smoke right now and even in winter I'm not sure that the white "smoke" coming out of the tower is materially differant than the "smoke" coming out of millions of homes.
I know one of the contractors who installed scrubbers in the exhaust stacks and periodically installs revised ones or other cleaning gear..
I understand about transmission losses when dealing with electrical energy.. On the surface that doesn't seem to be a significant issue since natural gas also has pumping costs and while I cannot say with any absolute certainty I wonder which is worse when you consider that the cost per therm is about the same..
Finally A boiler will cost nearly 5 times what I paid for seperate water heaters, one 80 gallon one for radiant heat and one 50 gallon one for domestic hot water..
Last but not least I still have the high efficency forced air furnace fired by natural gas as a back up.. It's reasonably new, in excellant order and checked annually by the gas company.
" I wonder why you feel that it was fiction that I had a 4 inch hole letting heat out 24/7/365 when I used natural gas to heat with?"
Mainly, May through September. Do you think there would be any heat leaving your house today, with the 100 plus high temperatures forcast. Unless you are in the habit of heating your basement beyond minimal needs, you could potentially gravity vent a minimal amount of heat out during colder periods. There is what is call a flue damper to prevent this, for those who are experienced in such. Personally, I believe that, if your were to use gravity vented appliances, then you are more concerned about cheap than efficient.
"However every single report I've read says that Natural gas is getting more expensive as well.. so if electric costs increase at worst they will increase with the increase in natural gas.. "
This is your supposition, one that your that your acknowledgment of the overdue electrical price adustment, further makes invalid. I am very familiar with the power industry in the midwest and the utility boards that regulate them. I worked for a large utility, prior to deregulation. I can assure you that, though it takes time, they will get their price increase and it will be enough to cover not only the lag that presently exists, but the reasonably predicted increases in the future.
"I'm not sure that the visable black smoke is really the problem.. "
Visual inspection by an uninformed "layman" means absolutely nothing. Can you see CO2 in the air you exhale? Can you see the CO leaving the exhaust pipe of a car that runs well?
" ...boiler will cost nearly 5 times what I paid for seperate water heaters,"
So the bottom line here is that you're cheap. You use what I consider BS reasoning, to justify that. Your world, your version of reality, your house, your money, your choice. Eventually, it'll be your problem, or that of the unfortunate soul that purchases your home.
Edited 7/31/2006 10:00 am by Tim
Tim Please,
Call me frugal if you wish I fully accept that. But since I will spend whatever is called for I am not cheap!
My house is built with decay resistant woods far far beyond any requirement.. I also used stainless steel bolts which will never be seen for durability reasons..Plus countless other things where cost is a secondary consideration.
If I were convinced that a boiler was the correct and most efficent method to heat my house You couldn't keep me from installing one..
I'm not! I've spent countless hours doing research, listening to people and checking facts..
As I've said I will have not only the in floor radiant heat, two gas fireplaces and the oversized forced air furnace..
If my calculations are incorrect I can quickly replace the electric water heaters with a boiler..
Right now costs per therm are the same.. There is a tremendous amount of untapped electrical generation already in and being paid for.. (recent laws forced that to happen) There are no new sources of natural gas not being exploited.
If you are correct in the the position you've taken then I will not lose that much when and if I am forced to reconvert to natural gas as a heating source..
I did take a short cut when I spoke about visable smoke.. I am aware of the real problem with stack emmisions not only to global warming but also to acid rain production..
However I also drive by two refining plants and notice they have exhaust stacks as well. Add in the effect of millions of homes heated by natural gas and suddenly it's a pretty tough call to make which is worse from an eviornmental standpoint..
This far everything is about feelings, you feel strongly this way while I feel equaly strongly another.
Can you provide me with some actual case studies that would reflect todays situation? When I asked for that from my local Gas company, the literature they sent wasn't in the least objective.. Plus they spoke in such generatlities as to be nearly worthless.
What I really need is the equivalent of a Consumers Report.
Well informed,neutral and complete..
Finally heat loss in the summer isn't an issue. heat loss in the winter is.. I know of nobody who will open a window intheir house when the outside temp is as cold as it gets here in Minnesota. Ok a few wackos aside <G> but that is the effect of a exhaust stack out the roof.
You speak of dampers..
The R value of that plate of metal across the flue pipe is what?
I'll bet it's nowhere near the R 50 I have in my ceiling! In fact when the water heater is off the flue pipe is positively cold and that's in the basement after being warmed by three floors worth of heat!
If there is no heat loss in the summer through your 4" hole, then its not a 24/7/365 heat loss, is it? Kind of a huge exaggeartion on your part. As I stated, with outside air above 60 degrees, fully 6 months of the year, there is no draft unless its firing, or cooling shortly thereafter.
The reality is that compared to a 5000 sf house, even a well insulated one, unitended draft losses through such is insignificant, and conduction losses are far less. If one were interested in both effieciency and air infiltration, not using electricity as a heat source, then sealed combusion is the best option, ducted combustion air to a closed mechanical room with induced draft being another good option.
"Can you provide me with some actual case studies that would reflect todays situation? "
Not readily. My subscription to Power magazine lapsed years ago. Though, that publication and there are several similar ones as well, is an excellent source of information concerning the trends and issues affecting the cost to produce, transmit and sell power in the commercial electric utility market place. My recollection, is that as I have paid attention to energy issues over the years, from whatever source attainable, is that it is a relative constant beleif throughout the industry, especially in light of California's two year debalcle AND the significant increase in the cost of natural gas, etc., that electricity is presently underpriced and due for an increase.
Ive done many an oil to gas conversion , propane is fine. If the soil is sandy or loose bury the tank. When the soil is hard tanks are set above ground ( you will need at least two due to slow evaporation of propane during the winter) If your budget is 5- 10k you can get new tanks and boiler . Iwould also suggest a seperate hot water storage tank instead of a tankless coil it stores hot water efficiently like a thermos and many have lifetime warrantys. It may cost a bit more but it's worth it, it also can produce far more hot water per an hour. For probably closer to 20k you can get a radiant floor panel system installed . You need some one with alot of experience for this. Local Master Plumber should be used . Its important to also have a heat loss study done on home , based on measurements of your home , windows , doors, and insulation values a competent plumber can generate on computer software programs a load calculation and correctly size boiler to your home . You dont want to install a V-8 in a car that just needs a 4 cylinder.
"you will need at least two due to slow evaporation of propane during the winter"
I live in northern IL with a single 500 gallon underground propane tank. Never had a problem. The bottom of the tank is below the average frost dept of 48". Evaporates fine down to the 5% level, with lows in the -15 degF range. On what do you base this statement?
In most areas, propane is the most expensive fuel!! Do an economic analysis before you jump.
At the following website is a chart I put together in 1993 while I was the government energy analyst for our province: http://www.gov.ns.ca/energy/AbsPage.aspx?ID=1395&siteid=1&lang=1 It may help you start your analysis by substituting fuel costs for your area. It's a mix of metric (liters used here in Canada) and English units (BTU's) so a bit of conversion is necessary.
At the same site, there's a water heating cost chart and a "Hot Water Answers" brochure that is downloadable.
1. Is it possible to convert this to propane? Yes, it is possible, though in the NE is not likely going to be the most cost effective.
2. As propane a good idea? My alternative is an outside tank that has to be kerosene. That would depend on the operating costs. From various conversations with folks in the northeast over the years, I believe that its hard to beat the value of fuel oil for heating in your area.
3. What is it likely to cost ballpark?A small (80,000 btuh) LP condensing, modulating boiler (i.e. high efficiency and can be vented with PVC) lists for abour $3400. I bought a 500 gallon underground LP tank for $350, plust the trade-in for my above ground tank.
4. The slab is likely to be cold in the winter - I was getting ready to have engineered wood floors installed.. Can I put radiant heat there instead fueled by the same boiler that does the upstairs baseboards? Absolutely. Many manufacturers have products made just for that.
5. Can I put the engineered wood over the tubing? If your talking about an enginnered finished wood flooring, absolutely. The laminated, floating wood floors work well over a warmboard or raupanel.
6. Is there a good product that would insulate the floor from the cold of the concrete? Rigid foam (extruded polystyrene) board is very good for this, will support 25 lbs/sq inch without denting, and can be bought in thickness from 1/2" to 2". Covered with some subflooring like osb or plywood, makes and excellent thermal break from the cold concrete and is rigid enough to set tile (with the appropriate backer) without worries of cracking grout. I used 1/2"EPS with 3/8" plywood, and 3/8" cementitious backerboard to put an electrically heated tile floor over a concrete slab on grade, and I am ver pleased with it.
Edited 7/28/2006 1:23 pm by Tim
Hi Tim,just a niggling little point that may not even apply here, but I've been running some numbers on oil vs gas up here in the northeast on a few homes lately, and it's looking like the difference isn't so big, IF you are comparing a conventional oil boiler vs a mod/con gas/propane boiler.In fact, it all depends on how charitable you want to be for the conventional boiler and how well it's controlled. You know your stuff so I imagine if you're drawing something up for someone it'll be done well, but the difference isn't naturally so large these days with the fairly wide efficiency differential between mod/con and conventional boilers.. admittedly, much moreso with lower temperature systems. But a nice 140 degree BB system w/a 20 degree drop to return water would see some real benefit.don't forget maintenance costs as well, in that comparison.-------------------------------------
-=Northeast Radiant Technology=-
Radiant Design, Consultation, Parts Supply
http://www.NRTradiant.com
My experience with oil is limited its use as a lubricant. So I leave this evaluation to the regional folks that have experience with fuel oil. However, with similar type of boilers or furnaces you will have similar seasonal efficiency for the two fuels, correct?
So the cost, the volatility of the cost and/or the ability to contract at a seasonal "locked in" price, would be, it seems to me, the primary factors to consider in deciding between gas, lp or fuel oil. I suppose, that the presence of competition for your business is a factor as well.
I have the choice (at my residence out in the sticks) between electricity at $0.08/kWh vs LP at $1.51/gal (based on my last years contract, I'll be getting this year's options within then next few weeks).
BTW, I am in the process of designing a boiler replacment for an school built in the mid 50's. The behemoth old steam (converted to gravity hot water, then hacked into a semi-pumped, kinda zoned HW system) boiler is being replaced with two Patterson-Kelley natural gas condensing, modulating Mach series boilers, VFD's on the system pumps and with HWS as low as 130 w/ODR.for the old stuff, and a 30 degree DT, We're estimating, conservatively Ithink, approximately 50 to 60% efficency gains, in part load conditions. IF this system has to operate on a "design plus" day (for me that's -15 OAT), it'll be at "standard" conditions, ie. 180/160, and an AFUE at 85% (an improvement of only 25-30% over the present). IF I had the opportunity (or the school had the budget ;p) and could select all the coils for lower temperature supply and higher dT's, we could get the savings up another 10% or so.
Speaking of charity for convention, I read that article John R on the Wall was so spun up about, and it lead me to look into the real determination of AFUE. The process is very complex, but one fact is that boilers, condensing or not, are tested with 80 degF return water. You can count on that generosity being good for 15 to 20 points of efficiency. Real world tests would be nice in this area.
Edited 7/28/2006 3:54 pm by Tim
Wow, great stuff there Tim. I agree with similar boilers you'd get similar efficiency and oil would kick arse hands down out here.But the comparison I keep running into is conventional oil boiler vs mod/con gas or propane, not between similar boilers. and in such a circumstance.. it all depends on how charitable you are to the oil boiler. With reset controls, firing controls, proper maintenance, good sizing.. maybe you can approach the AFUE? Hard for me to say, that's beyond my expertise. Sounds like you have some pretty strong ideas on the matter though, and my partner would agree with you. He's operating on a 60% efficiency assumption for a conventional oil fired boiler in the field.In our niche of the heating world (radiant), I'm personally noting that it doesn't seem to make sense to use anything but gas/propane in a mod/con for heating any real load. Of course, electricity is fairly expensive up here too. For large loads, geothermal seems like a good choice nonetheless.For now! Two oil condensors are out.. now, as soon as low-sulphur oil becomes available on this side of the pond, a true mod/con for oil may bring it back into the game!Sure would be nice if those of us who are not boiler engineers had something more solid than AFUE to go on, eh? I think John's right on.-------------------------------------
-=Northeast Radiant Technology=-
Radiant Design, Consultation, Parts Supply
http://www.NRTradiant.com
I believe, though my knowledge of the details of the testing that is used to determine AFUE ratings IS limited (10CFR430, & ANSI/ASHRAE 103-1993 contain the mind numbing details) that a return water temperature (HWR) of 80 degF is used for hot water boilers. By using an invalid (by Engineering standards) comparison of the efficiency curves published by manufacturer's of condensing boilers based on HWR (and also on part load %), were you to compare the 100% load of a mod/con at 100 HWR to 160 HWR, you would see a 15 to 20% drop in combustion efficiency at the higher HWR. Fairly or not, you can reasonable apply the same drop in efficiency to a non-condensing boiler operating at "standard" conditions, ie. 180 HWS and 160 HWR. Starting in the low 80's (%) at best, reality is low 60's. I find it hard to agree with the ranting of JR, but he has a point. Had he the semblence of a more sane individual, he could possible make a difference.
Another reality I face, with my company engineering a lot of boiler replacements, is that all of the coils in the older buildings are typically designed for 180/160. It makes taking full advantage of the mod/con replacements nearly impossible, without an entire system replacment. Conservatism on th part of the original designers helps with at least the ability to reset at off design conditions, which forms the bulk of the heating season anyways.
Hello there. Thanks for the information. An update. I gave up on the propane idea based on input from you all on this forum. I'll have an outside tank, which I'll need to enclose for aesthetics and if done right will allow me to use #2 fuel oil rather then #1. I see that I have many choices about the floor and the idea of putting in radiant heat over the slab is intriguing enough that I'll suspend my effort to get the engineered floor in between closing and moving day (seven days - starting on Thursday this week! ) to be a bit more planful and careful about how I'm spending my money. Thanks for the help.
"I have many choices about the floor and the idea of putting in radiant heat over the slab is intriguing..."
Glad to hear that we provided something useful for you. As I posted to NRTRob, my experience with fuel oil, regardless of its number is of no use to you or anyone else for that matter. Also, though I have some direct experience in radiant floor heat, there are professionals out there, such as Rob and his company, that are better suited than I to expose to you the best options. Good luck with your new home!
Regards,
Tim
Frenchy has good points about elec. water heaters.
Add heat pump or GSHP to your list of trade items.
In Son's house, redid the slab floor by laying down 1" sleepers with styrofoam, 1/2 ply over -- insulation is usually your best investment on energy reduction when you start from uninsulated or concrete slab scenarios. Then added a HP on top of the downflow nat gas furnace - the furnace has not been used since as the climate is mild enough that the HP is more cost effective (26 deg break point, seldom gets that low in PNW.)