anne in pa wrote:

We live in southeast PA, near Philadelphia.

Me too.

...Should we:

1. Replace the heat pump and add electric backup, eliminating the oil
furnace? Electricity here is about 14.5 cents/kwh, though supposedly
there's a discount for all-electric houses.

There is... Can you qualify if you keep the old furnace?

2. Replace the heat pump and keep the oil backup? The furnace is also
about 25 years old, but it hasn't run that much because it's backup
only. It tested at 82% efficiency last fall.

Sounds pretty good.

3. Make the oil furnace our primary heat and just replace the central air?

Maybe. With a large lean-to sunspace or "solar siding" over the south wall
of the house, the backup fuel bill may become unimportant.

I do like the feel of hot air coming out of the vents when it's cold.

A sunspace can do that too :-)

Nick

Tired of Iraq? Do something about it. Learn to halve your energy use
while having fun with math and science.

Join PE Drew Gillett and PhD Rich Komp and me for a workshop on Solar House
Heating and Natural Cooling Strategies at the first Pennsylvania Renewable
Energy Festival on Saturday September 24, 2005 near Allentown. See

http://www.paenergyfest.com/workshop-info.shtml