Electric or Oil (apartment, big house, heat pump)

[PacoMartin]

The home is 80 years old, and quite large. It has steam-fired radiator system, with an oil boiler (circa 1994). At 85% efficiency it is high quality boiler, and the company has not updated it.

A gallon of home heating oil (HHO) is thermally equivalent to 40.6 kWh of electricity. If electricity goes as low as 10 cents per kWh, and HHO is $4.06 per gallon they cost the same from the point of cost per unit energy (Therms, BTU's, Joules, etc.)

But given the efficiency of the boiler, and the relative inefficiency of lack of zone heating, I think that they are already at equivalent. The problem is that this equivalence has only come true in the last year. Prior to that, and for the last century, oil was much cheaper.

Here is the data on HHO use in the house for the last four winters.
2008/00 2,042.0 $4,000
2009/10 1,665.8 $3,579
2010/11 1,877.4 $5,621
2011/12 1,618.5 $5,700

My concern is that a nasty winter next year will drive use back up to 2,000 gallons. HHO could soar past $4 per gallon, meaning oil bill could go to $8K-$9K. If gas was available in the neighborhood it would be a no brainer to convert. But UGI may never come here because it is small isolated neighborhood.

But electricity could offer big savings in zone heating. Unoccupied rooms could be reduced to 50 degrees. The large basement (over 4000 sq ft) seems to use up a lot of the oil heat.

On first look, 2000 gallons equals over 80,000 kWh of electricity. If they cost the same, it seems as if you should be able to zone heat a house for a fraction of that power.

It seems risky to rip out this 80 year old heating system and put in radiant electric heat. There is easily 4 tons of radiators.

More importantly, what if the situation should reverse again in a few years? Two years HHO was $2.15/gallon and electricity was 12.2 cents per kWh. At that point HHO was about double the price of electricity on a per energy basis.

I don't think such old houses can be retrofitted with heat pumps. I have been combing the internet for months looking at all kinds of systems, but there are poor choices for retrofits (lots of good ideas for new construction).

[alexiskai]

Can you retrofit with zone heating alone? We also have a large house, very very old, bad insulation. We heat only one floor and our bills are about half yours.

[PacoMartin]

https://lh5.googleusercontent.com/YPCkN-0kiadToUyq-GlYL1o-acfRa8-K55y1TN7Pr_X3Bciqmo97G2cByIxNbd2dd8X2KyScwM1JvHXKG o-gGDrWlUdPKp5r21xSc3IGRDYF (broken link)

It's a pretty big house. About 4366 sq ft on first floor (56' by 78'). It has two towers that about 250 sq ft apiece that stick up with windows on 3 sides. Very large basement (over 4000 sq ft). Detached 3 car garage with apartment that has separate boiler.

We try to zone heat as much as possible by turning off radiators. But the system built in 1930 didn't even think about energy costs. You just had a man who shoveled coal in the basement.

I tried to figure out the kWh of the radiators by their individual characteristics. The total effective square feet of the radiators is 957 square feet.


We have an SGO-8 (http://www.weil-mclain.com/en/our-products/boilers/oil-fired-boiler/sgo-oil-boiler.aspx - broken link) which is rated for 833 square feet of steam. It's the 2nd biggest residential model they make. They should have bought the biggest (rated at 921 sq ft), but it didn't fit down the stairs.

The radiators in the center of the house were removed about 40 years ago, so a pellet stove was installed to heat that portion of the house.

[valentine92]

We are still trying to decide what type of electric heat to install since coming off oil. Air source heat pump, but will it keep the house warm enough, or electric baseboard heaters. I am so done with oil and wont even consider propane. Unfortunately natural gas is not an option.

[PacoMartin]

Originally Posted by valentine92

We are still trying to decide what type of electric heat to install since coming off oil. Air source heat pump, but will it keep the house warm enough, or electric baseboard heaters. I am so done with oil and wont even consider propane. Unfortunately natural gas is not an option.

Like you, natural gas is not an option for us because there are no mains.

Just a quick calculation:
66% usage *1500 Watt heat *24 hours/day* 100 days * 8 heaters = 19,008 kWh

For 1000 gallons of home heating oil = 40,600 kWh

With oil and electricity nearly the same price per kWh, it seems like you have to save money.

The 66% usage rate seems justifiable, because sometimes you are not on full power, and sometimes the thermostat kicks in. Plus during the day it usually isn't that cold. Plus you turn down rooms that you are not in.