On Sun, 20 Feb 2005 13:34:25 -0800, "Zyp" wrote:

John;

This may be a bit lengthy but I'll try to explain as breifly as possible.

The only way you can compare one unit to another [efficiency] is work in the
same language. In other words, heat [btu/h]. Capacity vs. energy consumed.

To relate, a heat pump is measured in HSPF [Heating
Seasonal Performance Factor] and COP [Coefficient of Performance.] Both
have relationship [ratio] between the energy consumed vs. heat energy
delivered.

A furnace on the other hand consumes natural gas or propane gas and delivers
heat energy vs. energy consumed and has a specifiec amount of waster AFUE
[American Fuel Utilization Efficienty]

The easiest way to make a comparison is to convert the energy the 'heat
pump' uses [kWh] to btu/h. (3413 btu/h per kWh). Then compare the amount
of btu/h energy delivered to the occupied space. This is representative of
the COP. [A heat pump with a COP of say 2.0 has a 'coefficent' of 200% as
compared to a electric strip heater of the same capacity.] Keep in mind
though, that when the conditions change [outdoor temp's] the COP decreases
as well as the capacity delivered.

On the other hand, a natural gas furnace delivers the same btu/h no matter
what the outdoor temperature is. But, is either 80% efficient or 90% - 93%
depending on the model. The remainder of the which goes up the flu stack.

When you compare $ for $ [which if you ask, I will be happy to send you a
power point presentation based on the costs associated with different energy
sources and different uses] you would find a heat pump actually is just as
effient as a gas fired heater,

On Sun, 20 Feb 2005 , p j m@see _my _sig _for_address.com replied:

Nonsequitor. That's like saying the moon is as low as water -
it simply doesn't make any sense at all, it's gibberish.

What you meant to say was 'cost effective'. This can only be
computed when fuel costs are known and stated ( gas v oil v
electricity ).

OK: Here they a

Assume 8.27 cents per KwH (current cost is 6.89 cents for a marginal KwH,
but the Administration's FY2006 budget proposal assumes BPA will raise
their rates 20% to 'market', therefore I will assume that will occur)

Assume 1.18 cents per marginal Therm.

The existing energy use is 671 Therms/year for heating with the old and
failing furnace, and 1,059 KwH for cooling (A/C only heat pump).

snip

IOW - even at 30 F or less, a heat pump continues to provide
economical heat. Now, it may very well not provide *ALL* the heat you
need at that point, but what heat it DOES provide is less expensive
than anything else, such as fuel-fired, etc, *IF* the fuel costs made
sense to begin with.

Please don't assume there's any logic to fuel pricing. It's market driven,
and the marketeers in this case include Enron's Portland General Electric.

The economic balance point is derived from the cost of fuels
and electricity at the time. In areas with high gas/oil costs and low
KW costs, it makes sense. In areas with high KW costs and low oil/gas
costs, it does not.

Given the data above, what's your take on the matter at hand?

It may be helpful to visit
tinyurl.com/64pq6
which is an EPA site with an estimator program, with my data already
entered. However, I am uncertain of several of their assumptions.


The optimum solution, so far, seems to be a 90% furmace, as over ten years
it looks less expensive than the 80% also proposed. Here is the data,
transposed from an Excel spreadsheet:

Dealer estimate
Gross price
state rebate
net up front cost
finance cost
total furnace cost
est yearly fuel cost (based on projected fuel cost * old furnace efficiency
/ new furnace efficiency)
5 year cost
10 year cost
15 year cost
(All figures in current dollars)

I'd be happy to send the spreadsheet by e-mail if desired.

Projected gas cost is 1.03 * current fuel cost, based on EPA demand
projections of a 3% increase. Very rough, not at all accurate, but best
available in a short period of time.

Dealer estimate for REPAIR
Gross price = $1,560
state rebate = $0
net up front cost = $1,560
finance cost = $0
total furnace cost = $1,560
est yearly fuel cost = $812
5 year cost = $7,181 (assumes re-repair every 5 yr., same cost)
10 year cost = $14,363
15 year cost = $21,544

Dealer estimate for REPLACE W/ 80% EFFICIENT FURNACE
Gross price = $ 2,600
state rebate = $0
net up front cost = $2,600
finance cost = $7 on balance we can't pay for immediately
total furnace cost = $2,607
est yearly fuel cost = $711
5 year cost = $6,161
10 year cost = $9,714
15 year cost = $13,268

Dealer estimate for REPLACE W/ 90% EFFICIENT FURNACE
Gross price = $3,400
state rebate = $200
net up front cost = $3,200
finance cost = $49
total furnace cost = $3,249
est yearly fuel cost = $632
5 year cost = $6,408
10 year cost = $9,567
15 year cost = $12,725

Dealer estimate for REPLACE W/ 94% EFFICIENT FURNACE
Gross price = $4,700
state rebate = $550
net up front cost = $4,150
finance cost = $116
total furnace cost = $4,266
est yearly fuel cost = $605
5 year cost = $7,290
10 year cost = $10,314
15 year cost = $13,339

A very rough estimate of an air-air heat pump to replace both the exisiting
A/C only heat pump and the gas furnace follows. It deducts our current
estimated A/C energy cost from the total energy cost for the 5, 10 and 15
year projections, and uses that 20% hike in electrical cost I mentioned
above.

It uses the EPA's website (op cit.) ballpark price for an air-air heat pump
with HSFP 8.5 & SEER 13 of $4,800, and adds $500 for each step up in
effiiciency. It also assumes the existing duct work, which serves us well
for summer A/C needs, would be servicable for winter heating. None of
these assumptions are sacred, and any improvements in accuracy you suggest
would be eagerly listened to, as we have two more estimators from diferent
HVAC companies coming tomorrow, and we'd like to make a decision soon after
the last departs.

Ballpark estimate for REPLACE W/ HEAT PUMP, HSFP 8.5 SEER 13
Gross price = $ 4,800
state rebate = $500
net up front cost = $4,300
finance cost = $126 on balance we can't pay for immediately
total replacement cost = $4,426
est yearly energy cost = $811
5 year cost = $8,043 (adjusting for greater cooling efficiency)
10 year cost = $11,660
15 year cost = $15,227

Ballpark estimate for REPLACE W/ HEAT PUMP, HSFP 9 SEER 13.5
Gross price = $ 5,300
state rebate = $600
net up front cost = $4,700
finance cost = $154 on balance we can't pay for immediately
total replacement cost = $4,854
est yearly energy cost = $768
5 year cost = $8,256 (adjusting for greater cooling efficiency)
10 year cost = $11,658
15 year cost = $15,060

Ballpark estimate for REPLACE W/ HEAT PUMP, HSFP 9.5 SEER 14
Gross price = $ 5,800
state rebate = $700
net up front cost = $5,100
finance cost = $182 on balance we can't pay for immediately
total replacement cost = $5,282
est yearly energy cost = $730
5 year cost = $8,494 (adjusting for greater cooling efficiency)
10 year cost = $11,706
15 year cost = $14,918

BTW, I made several hours of attempts to find anyone in the Portland (OR)
metro area who was competent to discuss ground source heat pumps. The one
designer I found, who did the People's Food Co-Op system, said the
underlying basalt where our home is (said homesite having been selected to
avoid soil liquification when the Big One hits) makes vertical well
drilling very chancy. That was confirmed by a local well driller, who did
some well work about a quarter mile from here. The largest open space we
have for a slinky layout is 30' x 60', which makes me think I don't have
the room for a ground source heat sink.

And, BTW, Paul, have you considered offering your expertise to other Palm
Users? PalmSource offers their Expert Guides, and I see there is no HVAC
guide. The compensation is modest, but you may find it worthwhile.

http://www.palmsource.com/expertguides/


Thank you kindly.


--
K7AAY John Bartley Portland OR USA views are mine, all mine.
http://kiloseven.blogspot.com
"The Temporal Office says you have to do this. No, no explanation.
Here's your stuffed tuna and an airhorn." - James Nicoll