Conversion to Propane

scrook_2

on the typical propane to #2 oil pricing in your region. For equal BTU/dollar propane needs the price per gallon to be 2/3rd's the price of oil (or: oil at 1.5X propane per gallon).

Whatever the prevailing price difference, you'd need to compare combustion efficiencies, say you are getting 84% w/ the W-M and you could get 90% with the propane then adjust the propane price by (.84/.90)*$/gal propane then multiply by 1.5 for equivalent oil cost.

Say (numbers out of a hat) oil's $2.40/gal and propane's only $1.70/ gal and combustion eff's are 84% oil & 90% propane then (.84/.90)*$1.80*1.5 = $2.38/gal equivalent oil, so propane's basically equal in cost. This ignores the up front conversion cost, which you wouldn't live long enough to recoup in this example.

Here's a link for current regional oil and propane prices:
http://tonto.eia.doe.gov/dnav/pet/pet_pri_wfr_dcus_nus_w.htm

In PA, oil's presently (03/16/09) about $2.10/gal and propane's about $2.76/gal (propane's an expensive fuel!), (NJ is about $2.18 & $3.01)

With these prices even (absurd case...) if propane was 100% eff and the oil was only 55% eff you'd STILL be paying more to burn propane! Check your area's prevailing prices.

Note too an unstated assumption: propane and oil prices will probably track closely over time, closer than short term tracking of either to NG. Again depending where you are NG may, most years, be attractive in total delivered cost (e.g. toward the Gulf Coast or South Central US) or not (e.g. towards the Northeast US), though short term NG should be much less volatile in price than either oil or propane, and requires no on site storage -- but you have to be next to a gas main.

Jlacomis

Conversion to Propane

I built a 3000 SF 100 % radiant house in NE pa in 2004. With the slab, there is a total of about 4900SF of radiant. The primary heat source is a WM Gold oil-fired with a 60ga Gold Indirect. There are 3-1/2 baths with the potential for 4-1/2 if I ever finish the basement. I've been kicking around the idea of converting over to a propane fired condensing boiler and tankless water heater. I've installed several Noritz tankless since I built my own and am very impressed. I've used them for DWH and most recently for a 1500 SF basement slab in a hot-air home. Every condensing I have installed to date is NG and I realize there would be some efficeincy losses in Propane fired units.
Ok..here's the question.. would the higher efficiencies of the condensing units, on-demand DHW, and lower water temps on the heating side (I mix down now for the radiant on the WM gold) offset the lower BTU/$ of Propane vs Oil? Does anyone have a spreadsheet to plug in the numbers to look at a possible ROI?
TX,
JIm

Vernon P. James_2

conversion

Stick with fuel oil as long as the price stays below $4.00 a gallon. I had a 86% eff high mass dynatherm oil boiler with coil in it running at constant 170 degrees to make hot water. I installed a new propane mod-con a year ago last December expecting to save. I am about 4000 sq ft and all plated or quick trac radiant. I have the mod-con running at 140 max at -20 outdoor on reset so at around 10 outdoor it runs at about 120 degrees. It is a combi unit that is basically the same as a stand alone tankless for hot water. We have 3 kids two of which are teenagers so we use a lot of hot water. The mod con runs about 95% eff most of the time. Without going technical by degree days and all of that I can tell you I use so much propane I am considering changing back to oil. On oil during the cold part of the winter which is usually from December 1 thru April 1 here in Saranac Lake in the Adirondacks I averaged about 250 gallons of oil every 30 days. With the new mod-con I have been running 200 gallons propane every 21 days. I can't complain on the operation of the mod-con. It is a marvel to watch the tiny little thing come on and it go from 50 deg to 120 degree boiler temp in about 1 minute and it provides enough domestic hot water to support 2 showers at once constant but I am paying a lot more to have that marvel. Propane price here started at $3.10 last December When oil was $4.00. This year propane has been steady at $2.30 and oil has gone from $2.20- 2.80.