monthly average temps historic ?

[Stan]

If I divide therms consumed (I'm using gallons of oil) by the total HDD's for a heating season I get a number like .1765 for one season and .2000 for a second season. What does that mean ? That I consumed 13.3% more oil adjusted for the temperature in the second season or that I consumed 11.75% less oil adjusted for the temperature in the second season, or something else entirely ?

I interpret that to mean that you consumed more therms per heating degree day the second year. If you installed the insulation and windows between the first and second heating season, they don't appear to be paying for themselves on the surface.

Averages can be very misleading however and there could be a number of explanations for this unrelated to your improvements. First, the period of time examined should be the same in each year. Heating systems generally operate at a higher efficiency during peak season than the shoulder seasons.

Second, the oil in the tank should be the same at the beginning of each period and the same at the end of each period. Otherwise, you are counting fuel for the wrong time period.

Third, other factors could impact your results ... was the oil burner tuned up one season and not tuned up the other season? if your hot water is fueled by oil, was there a change in hot water consumption? etc.

Sometimes the best result of an analysis like this is not just in the obvious calculation but in examining the explanation behind it.

 

[Kevin Rooney]

Chip -

Do you have an electronic thermostat which allows for a few automatic setbacks? If not, spend $35 or so on one. They're not difficult to install, and can make a huge difference not only in fuel savings, but comfort as well. When my wife & I lived in VT we had a reasonably well-insulated house, double-paned windows with storms, modern boiler, etc - with an older mercury rocker switch for a thermostat. We were forever adjusting it - she up because she was cold, me down because I was sweating. After about 15 years I installed a new electronic one - after that, both of us were always comfortable, and we saved $$ on fuel. And, there were no sideways conversations about "someone's been adjusting the thermostat".

 

[Chip]

okay, real numbers are (yesterday I was trying to remember); 07/08 season is .2327 and 08/09 season (after windows) was .1719. So that's, what, a 26%reduction ? I added the insulation this fall, so the 09/10 number will reflect that. Thanks for all your help.

 

[smitty77]

okay, real numbers are (yesterday I was trying to remember); 07/08 season is .2327 and 08/09 season (after windows) was .1719. So that's, what, a 26%reduction ? I added the insulation this fall, so the 09/10 number will reflect that. Thanks for all your help.

Very nice! I like improvements that pay for themselves. I thought your previous data "from memory" was flawed. I started covering the second floor windows with shrinkable plastic and it made a noticeable difference in comfort, so your windows and insulation HAD to make a difference that you could see in the numbers.

And speaking of drafty windows... My house is 6 years old and the cheap vinyl windows the contractor put in are very drafty. The tilt-in feature is great for cleaning, but they leak a LOT of air (which is why I cover them in plastic). The plastic is a pain to hang so that it doesn't look too "redneck" and new windows aren't in the budget. Has anyone used that removable caulk? How "removable" is it and could I pop the window open with some force in case of emergency? I like peakbagger's idea of cellular blinds. I might give those a try too.

 

[jniehof]

Has anyone used that removable caulk?

The "Seal-and-peel" (comes in a tube) is not very removable...moreso than normal caulk, but not really something you could open in an emergency. You can also buy boxes of grey weatherstripping that's cut to roughly bead size, it peels off the roll and gets pressed into the cracks. A lot like firm Play-Doh. It doesn't set up at all, easy to remove, and doesn't keep you from opening the window. It is, however, fairly finicky to install. And I can't for the life of me remember what it's called.