Well first off EXCALIBER, home heating LP is not $4.oo per gallon and never has been. Right now I believe the national average is about $2.75 (up a bit over last year) and the price is dropping; in this area it’s around $2.50 per gallon. Second, if you go back and read my post, I explained that to be realistic the furnace would not run 100-precent of the time, more like 65-percent of the time during those 40-hours. So if we take your number of 171-gallons a week, 65-percent of that would be 111-gallons, at $2.75 that comes out at $305.oo a week (less than half your number). And that would only be during the coldest week of the year, most other weeks would use quite a bit less.
And by-the-way, it isn’t out of the realistic to burn over 100-gallons of LP a week, heating 2000 square feet during the coldest month of the year. Two years ago I heated 100-percent with LP, and my home is relatively small; a single story farm house at 1350 square feet… I used 400-gallons in less than 5-weeks during the cold spell that year (and it wasn’t as cold as this last year was). Thankfully I was only paying $1.73 per gallon at that time, but it still cost me near $700.oo to heat that month. It was the price increase last year ($2.25 last fall) that prompted me to start heating the home with wood again. We heated 99.9-percent with wood last year, but we still need the LP for the water heater… We’ve only used a tick over 300-gallons since last Halloween.
Here's a link to a calculation guide to what size furnace (in BTU's) you should install based on home size and area... I live in zone 5 (the blue zone) and at 2000 square feet it recommends a furnace of 100,000-110,000 BTU's.
eBay Guides - How many Btu s do I need to heat my home
And by-the-way, it isn’t out of the realistic to burn over 100-gallons of LP a week, heating 2000 square feet during the coldest month of the year. Two years ago I heated 100-percent with LP, and my home is relatively small; a single story farm house at 1350 square feet… I used 400-gallons in less than 5-weeks during the cold spell that year (and it wasn’t as cold as this last year was). Thankfully I was only paying $1.73 per gallon at that time, but it still cost me near $700.oo to heat that month. It was the price increase last year ($2.25 last fall) that prompted me to start heating the home with wood again. We heated 99.9-percent with wood last year, but we still need the LP for the water heater… We’ve only used a tick over 300-gallons since last Halloween.
Here's a link to a calculation guide to what size furnace (in BTU's) you should install based on home size and area... I live in zone 5 (the blue zone) and at 2000 square feet it recommends a furnace of 100,000-110,000 BTU's.
eBay Guides - How many Btu s do I need to heat my home