Heat Pump or Not? Please Help
Elizabeth Foltz
We are going to build our new home this year and are in the planning
stages right now. We are building a 1-1/2 story house with about 2800
square feet of living space. We cannot decide whether to go with a
conventional heating & cooling system or a heat pump/geothermal system.
We like the idea of the more environmentally friendly heat pump, but are
concerned about its efficiency and ability to really keep our house
cool in summer and warm in winter. Since we live in southeast Texas,
obviously keeping cool is the bigger concern for us, however, we can
usually expect two to three weeks of really cold temps each winter.
Questions:
1. If we go with the heat pump, can we really expect to recoup
our investment over time due to reduced electricity bills?
2. Can there be temperature control problems with the system
(too hot/too cold) that we will not be able to adjust?
3. Is the heat pump system adequate for all heating and cooling
needs, or will we need some alternative back-up system?
4. Would we be able to achieve the cost savings and efficiency we
desire by using a conventional system along with good insulation,
windows, ceiling fans, system zoning, etc..? P.S. Our 5-acre lot
is HEAVILY wooded -- plenty of shade.
Any advice or comments from heat pump consumers would be tremendously
appreciated. No e-mail please -- just post replies to this group.
Thanks,
Liz Foltz
Larry Madole
>Hi Ya'll,
>Any advice or comments from heat pump consumers would be tremendously
>appreciated. No e-mail please -- just post replies to this group.
>
>Thanks,
>
>Liz Foltz
>
bought the heat pump yet! In the words of one building expert guru who
is on the radio down here in Space City: "Heat pumps were designed by
Yankees, built by Yankees, sold by Yankees and by damn, they should use
them and leave us alone".
Leaving the chauvanism aside, his point is that heat pumps are designed
for climates where there is a substantial difference during cold weather
between indoor and outdoor ambient temperatures. Other than a few days a
year we just don't have that in Texas. Most of the "winter" our
temperatures are not low enough to justify a heat pump.
Local utilities push them. They are highly profitable for them to sell.
That doesn't make them a wise investment.
For really good information contact Florida State University which has a
department that has done outstanding research on heating and cooling of
buildings with southern emphasis. I know they have fact sheets on heat
pumps.
Really take a good hard look at this before spending your money.
Larry Madole
on cooling and heating is Florida A & M, School of Architecture,
Tallahassee, FL 32307. Phone 904-599-3244
Elizabeth Foltz
Thanks for all the input. We are leaning away from
the heat pump at this time.
Liz
a3...@lehigh.edu
> writes:
>Hi Ya'll,
>
>We are going to build our new home this year and are in the planning
>stages right now. We are building a 1-1/2 story house with about 2800
>square feet of living space. We cannot decide whether to go with a
>conventional heating & cooling system or a heat pump/geothermal system.
>We like the idea of the more environmentally friendly heat pump, but are
>concerned about its efficiency and ability to really keep our house
>cool in summer and warm in winter. Since we live in southeast Texas,
>obviously keeping cool is the bigger concern for us, however, we can
>usually expect two to three weeks of really cold temps each winter.
>
>Questions:
>
>1. If we go with the heat pump, can we really expect to recoup
> our investment over time due to reduced electricity bills?
>
>2. Can there be temperature control problems with the system
> (too hot/too cold) that we will not be able to adjust?
>
>3. Is the heat pump system adequate for all heating and cooling
> needs, or will we need some alternative back-up system?
>
>4. Would we be able to achieve the cost savings and efficiency we
> desire by using a conventional system along with good insulation,
> windows, ceiling fans, system zoning, etc..? P.S. Our 5-acre lot
> is HEAVILY wooded -- plenty of shade.
>
>appreciated. No e-mail please -- just post replies to this group.
>
>Thanks,
>
>Liz Foltz
been selling real estate for 15 years, so I get to hear about the public's
likes and dislikes. We had a heat pump. I never felt warm in winter unless
we were operating on the expensive backup system. After about 7 years,
components of the system began to break down. I knew the system wasn't
working when faced with a $400 electric bill: the system was only using the
backup heat. Repairmen came out to fix components, and the next month we had
another $400 electric bill. Something else broke down. Then they told me the
average life expectancy of the heat pump is 7-10 years. So, rather than spend
money on another similar system which would only last another 7-10 years, we
spent the money on an oil boiler. I'm warm, the heating costs are cheaper
than my heat pump, and we're happy. I'm still using what's left of my old
system for central air. Pattie>
>
Kyle Harper
>Hi Ya'll,
>
>We are going to build our new home this year and are in the planning
>stages right now. We are building a 1-1/2 story house with about 2800
>square feet of living space. We cannot decide whether to go with a
>conventional heating & cooling system or a heat pump/geothermal system.
>We like the idea of the more environmentally friendly heat pump, but are
>concerned about its efficiency and ability to really keep our house
>cool in summer and warm in winter. Since we live in southeast Texas,
>obviously keeping cool is the bigger concern for us, however, we can
>usually expect two to three weeks of really cold temps each winter.
<stuff snipped>
>Any advice or comments from heat pump consumers would be tremendously
>appreciated. No e-mail please -- just post replies to this group.
>
>Thanks,
>
>Liz Foltz
>
Liz,
We had a geothermal heatpump installed a little over two years ago in a 3200+ sq ft home (...on 5 tree covered acres :-)...) and hav=
e been very satisfied with its comfort and performance. Our total electric bill is well within the estimates of what we were told to=
expect by the contractor, even though we are actually setting the temperatures a little more comfortable than we assumed for the en=
ergy analysis. Our toughest test so far was last month's deep freeze (end of January '96 in Texas), when we had 5 days of sub-freezi=
ng weather. During the coldest days of that storm (highs of teens and low twenties) I noted that we spent about $6/day in total ele=
ctricity. The system kept up just fine with perhaps a little assist from the fireplaces.
The following is a collection of conversations I have had with several people in this newsgroup during our evaluation, decision, i=
nstallation, and living with our geo-system. In its current form it is not a geothermal FAQ but it probably covers the topic fairly=
well as if it were. Feel free to follow up with me. Good luck.
Kyle-Harp...@email.sps.mot.com
Motorola, Inc.
Austin, Texas
--------- cut here -----------
>Here is some info I have saved regarding our geoheatpump installation and
>operation.
>
>We have lived in our new house (in Austin, Texas) equipped with a
>geothermal heatpump since mid March (1994). We've had a couple of months'
>electric bills come in and so far the system is running slightly better
>than expected, given the early heatwave central Texas is experiencing
>right now. We currently set the thermostat to 73 degrees AC and 68
>degrees heat
>'round the clock, and did not have the water heating feature turned on
>during
>the peak of the summer (due to errors in water heating plumbing, not the
>HVAC);
>April's electric bill was ~$75, May's was $95, June $125, July $135,
>August $135,
>September $135, October $80. We turned on the water preheating in
>September.
>We have yet to program the setback thermostat. We are pleased that
>it looks like we are going to heat/cool and supply hot water in our new
>3300 sq ft 2 story house on the same $$ it took to do the same in our
>previous 10 year old, 10 SEER compressor A/C & nat. gas furnace 1400 sq
>ft, 1 story house - total electric bill was estimated to be $110/month.
>(Cost of electricity here is ~7.5 cents per kwh going to ~9 cents/kwh
>next year.)
>More info on this if you want it ....
> ...The system was designed not to require backup/auxilary heating
>(however, we have two _efficient_ fireplaces we will use if ever
>required). What follows are clippings from some discussions I had with
>folks on the net during our house design/construction:
>-------------------------------------
> Expect to pay more for the heatpump unit itself plus add in the cost of
>laying the ground loop. In this part of Texas, its more economical to
>install a vertical ground loop (one consisting of a series of vertical
>wells drilled in the ground) installed, due to the solid limestone that
>starts 6"-18" below the ground surface that tend to make it difficult to
>cut a deep enough trench required to install a horizontal ground loop.
>From what I have gathered so far, this additional cost could be recooped
>in a reasonable time period, presuming that the ground-source heat pump
>system will need to kick-in the auxillary heating system ($$$$ unless its
>natural gas) far less often during January and February than the
>conventional heatpump does.
>--------------------------------------
>We do not have direct, long term experience with a ground source heatpump
>system yet. However, we are in the process of building a new home and
>after much number crunching and reference checking in our local area
>(Austin, Texas), we decided to go with a ground source heatpump system
>over a conventional air heatpump.
> Our house is a 3300 sq. ft. two story with 9 foot ceilings, double pane
>windows, and 7' deep porches on all sides and both floors. With this
>energy-conscious design and floorplan, the local electric utility
>specified a 5 ton heating and air conditioning system. (FYI: The 7'
>porches all around the outside saved us 1-1/2 tons of HVAC!)
> The contractor we selected (Tom Romberg of Action Mechanical, for those
>of you in Austin, phone: 512-836-2222) is installing a single WaterFurnace 5 ton system with 4
>damper-controlled zones. Unlike with an air heatpump system, we did not
>require any back-up heating capacity (no electric strip heating
>kicking-in to cause our electric bill to skyrocket in the middle of
>January and February). This system also heats all of our water for free
>during the air conditioning months and heats it more efficiently than gas
>or electric water heating during the heating months.
> The ground loop is a self-contained closed-loop system consisting of
>five vertically-bored holes, each being 250 feet deep. The advantage of
>a closed loop over an open loop is that there is no residue or mineral
>deposit to clog up the loop pump and plumbing.
> Our annual cost of heating, cooling, and water heating was estimated
>using the historical day-temperature "bin" data for Austin, Texas, and
>came out to be about $90-100/month. To be certain, the installation of
>this system costs more than that of a conventional air heatpump, with the
>cost of installing the ground loop representing 1/3 to 1/2 of the total
>cost. Even so, assuming a 7 cent per kilowatt-hour electricity cost, we
>expect to get a payback on the additional installation cost within 6-7
>years. If our cost of electricity goes up to 8-9 cents per
>kilowatt-hour, the payback period gets very much shorter. If you have
>the luxury of having a body of water on your property (pond, lake, river)
>to run a closed-loop through, you will save yourself the substantial cost
>of boring vertical holes or trenching.
>Suggestions for you if you do decide to go with a ground source heatpump:
>1. Start with as energy efficient house design as reasonably possible.
>** Saving a ton of HVAC through energy conservation is much less
>expensive than adding another ton of ground source heatpump.** (This is
>true with any type system, but is especially true of ground source
>systems). Use passive energy conservation techniques: Orient the house
>to optimize/screen the direct sunlight in Winter/Summer. Add shade
>trees. Design roof overhangs to elliminate/minimize direct sunlight on
>windows and exterior walls. Use energy efficient windows and good
>insulation/air infiltration techniques.
>2. If natural gas is available, ground source may not be as attractive
>an alternative. In most cases where natural gas is available, it is much
>less expensive than electricity. In these cases, it is usually optimal
>to heat with natural gas and cool with a high efficiency air conditioning
>compressor.
>3. Your shortest payback on the additional cost of a ground source
>heatpump will come with a system that supplies your hot water as well as
>heats and cools your house. In fact, you may find that unless you heat
>your water this way, the payback may be much much longer.
>4. You might think twice before installing a ground source system if you
>don't expect to live in your house longer than the payback period. You
>will not be able to command a higher price on the market for your house
>based solely on the ground source heat pump system you put in. This may
>change in the future as housing energy costs continue to rise (when have
>they ever gone down?) and home builders, homebuyers, and *mortgage
>lenders* become more aware of this "other type" of heatpump.
>5. Take advantage of any and every energy efficiency rebate program
>offered by your utility company to offset the cost of installing a ground
>source system. Many are beginning to offer higher rebates for ground
>source heatpumps than the equivalent air heatpumps.
>------------------------------------
> Here's the info on my installation:
>System: WaterFurnace AT057 2 speed 5 ton, with water heating
>desuperheater (preheats/maintains hot water supply using waste heat from
>heatpump in Summer, efficient heat from heatpump in Winter)
>Loop: 5 vertical bored holes 250' each
>Ducting: 4 damper-controlled zones
>Thermostat: Carrier 4 zone setback thermostat
>Warranty: 10 years on equipment parts & labor, 50 years on the loop, 2
>year on thermostat.
>Misc.: price also included venting for exhaust fans, kitchen hood, dryer,
>etc.
>Install Cost: $15,483 ... _ouch!_ ... (vs 12 SEER air HP @ $7,600)
>Rebates: $1,100 from electric utility
>Net Install Cost: $14,383 (vs 12 SEER air HP @ $6,500)
>Exp. annual operating cost: $893 (vs 12 SEER air HP + electr. water htr @
>$1,881)
>Expected payback period: (~7yrs @ $0.070/kwh, ~5yrs @ $.090/kwh)
>
>This is for a 3300 square foot two story in Austin, Texas. Around this
>part of Texas, its cheaper to install the loop in vertical holes than
>horizontal trenches because 6-18" below the surface, we typically hit
>solid limestone. The cost of using a (big) rock saw trencher to cut
>~1100 feet of 4-6' trench is much more expensive than boring 4-5 vertical
>holes. Your situation may be different. Whether you go vertical or
>horizontal, just be sure that the loop installer is certified for loop
>installation ** by the heat pump manufacturer **. Make sure they heat
>fuse the loop and its fittings. Walk away from them if they even suggest
>using glues, cement, or clamps to assemble the loop components.
>Historically, ground source systems have been unreliable for only two
>reasons: loop integrity failure and mineral deposit build-up in the
>plumbing (the big "-" on open loop systems; not a problem on closed loop
>systems with the right additives).
>-------------------------------------
>Remember that about half of that cost is the install of the loop.
>The per ton cost of a geo system is more than for a conventional HP or
>gas furnace. You'll want to find out how many tons of HVAC your specific
>climate and 2100 sq. ft. house requires and then determine what length
>loop you'll need given your ground temperature.
> So, you need to adjust my price accordingly. Your loop install
>techniques (vertical vs horizontal) and costs may vary. Nevertheless,
>the object of the game is to avoid installing (and _paying for_) more
>tonnage and loop than you need. A rule of thumb I'm hearing down here is
>"figure on about 250' of loop for each ton of HVAC." Whether they will
>go vertical bore or horizontal trench, you're going to pay by the foot.
>BTW, the system we chose was not the least expensive one bid. We had
>another contractor bid the job using equipment from Florida Heatpump (mfgr's phone #: 305-776-5471, Ft. Lauderdale, Florida) and
>it came in at about $1690 under the Waterfurnace system. A third
>contractor bid the job using Trane/Command-Aire equipment (mfgr's phone #:817-840-3244; Waco,Texas) for about the
>same price. We chose to go with the Waterfurnace System (mfgr's phone #: 219-478-5667; Fort Wayne, Indiana) anyway because
>of its slightly better warranty package and with it we got it down to a
>single unit with a two speed heat pump. Also, the contractor proposing
>the Waterfurnace-based system was overwhelmingly recommended for his
>ductwork installation quality and length of time installing geo systems
>(We were concerned about investing top dollar into the HVAC equipment
>only to have shoddy ductwork leak into the attic.)
>-----------------------------------
>That's what I have. Let me know if you have more questions.
>-Kyle
Kirk Kerekes
> >We are going to build our new home this year and are in the planning
> >stages right now.
[snip]
> >Since we live in southeast Texas,
> >obviously keeping cool is the bigger concern for us, however, we can
> >usually expect two to three weeks of really cold temps each winter.
> >
> >1. If we go with the heat pump, can we really expect to recoup
> > our investment over time due to reduced electricity bills?
Compared to a natural-gas system? no way.
> >2. Can there be temperature control problems with the system
> > (too hot/too cold) that we will not be able to adjust?
Yes, but that is of course true with any system.
> >3. Is the heat pump system adequate for all heating and cooling
> > needs, or will we need some alternative back-up system?
It will probably serve you fine until you go broke or it does.
> >4. Would we be able to achieve the cost savings and efficiency we
> > desire by using a conventional system along with good insulation,
> > windows, ceiling fans, system zoning, etc..? P.S. Our 5-acre lot
> > is HEAVILY wooded -- plenty of shade.
In TX, I would suspect that "conventional" is propane or natural gas --
and natural gas is dramatically less expensive to operate than a heat
pump, and dedicated AC is generally more efficient and much more durable
and reliable than a heat-pump.
If you don't want gas for some reason, look seriously at ceiling-mounted
radiant heating panels for heat (EnerJoy is one brand). In recent
government managed studies, such panels tested as less expensive to
operate than heat pumps, not even counting their extraordinary reliability
and painless zoning.
--
Kirk Kerekes
-----------------------------------------
- Perfection is Not an Available Option -
-----------------------------------------
William (Liam) Grant
Elizabeth Foltz <efo...@bcm.tmc.edu> wrote:
> We are going to build our new home this year and are in the planning
> square feet of living space. We cannot decide whether to go with a
> conventional heating & cooling system or a heat pump/geothermal system.
Considering the way you are phrasing this, I assume you are talking
about using something other than the air-air system that is quite
popular with developers now (cause it's cheap). Either ground or
water loop, right?
> We like the idea of the more environmentally friendly heat pump, but are
> concerned about its efficiency and ability to really keep our house
> cool in summer and warm in winter. Since we live in southeast Texas,
> obviously keeping cool is the bigger concern for us, however, we can
> usually expect two to three weeks of really cold temps each winter.
I am in Washington, DC, so while I have hot temperatures, they are not
is the same range. The AC seems to work like a dream from our point
of view. The heating is a lot more qualified. We have an air-air
system. These go south about 35degrees F. Are your really cold temps
below this temp? Ignore this problem if you have a ground or water
loop, the outside air temp doesn't matter if the loop is deep enough.
The year-round temp underground is about 50 degrees, well within the
efficient operating range of the heat pump.
> 1. If we go with the heat pump, can we really expect to recoup
> our investment over time due to reduced electricity bills?
As opposed to electric heating and AC, yes. The utility companies
will give people rebates around here for installing a high efficiency
heat pump. They're in it for the money, so I assume they've looked
into this issue.
> 2. Can there be temperature control problems with the system
> (too hot/too cold) that we will not be able to adjust?
Well, the problem with heat pumps no matter what type is that the
heating operates by incrementally increasing the room temp. If it's
70 and the 'stat is set for 74, the air coming in from the forced air
system is maybe 76. This will warm the room up without being
wastefull, but anyone sitting iin front of the vent will consider it a
cold breeze. Unless you like cold breezes (I do) this will be
unacceptable (ask my wife). You have to arrange furniture and vents
so as not to blow directly at someone.
> 3. Is the heat pump system adequate for all heating and cooling
> needs, or will we need some alternative back-up system?
In this area, heating backups are really necessary. The real problem
is that the standard backup the developers install is resistive
heating strips. Can you say, "Cheap to install, expensive to use." I
knew you could. I have seen comments by Canadians that they had
disabled their backup and never had a need for it. 'Course, these
were for the geothermal units.
> 4. Would we be able to achieve the cost savings and efficiency we
> desire by using a conventional system along with good insulation,
> windows, ceiling fans, system zoning, etc..? P.S. Our 5-acre lot
> is HEAVILY wooded -- plenty of shade.
Got me there. Good luck
--
William (Liam) Grant Gr...@itd.nrl.navy.mil
Naval Research Laboratory, Code 5541, Washington, D.C. 20375-5337
Voice (202) 767-0552, FAX (202) 767-1060
Gerald McFatridge
wrote:
>Elizabeth Foltz <efo...@bcm.tmc.edu> wrote:
>>Hi Ya'll,
>>Any advice or comments from heat pump consumers would be tremendously
>>appreciated. No e-mail please -- just post replies to this group.
>>
>>Thanks,
>>
>>Liz Foltz
>>
>Liz: Sharing life with you in the Lone Star leads me to hope you haven't
>bought the heat pump yet! In the words of one building expert guru who
>is on the radio down here in Space City: "Heat pumps were designed by
>Yankees, built by Yankees, sold by Yankees and by damn, they should use
>them and leave us alone".
>
>Leaving the chauvanism aside, his point is that heat pumps are designed
>for climates where there is a substantial difference during cold weather
>between indoor and outdoor ambient temperatures. Other than a few days a
>year we just don't have that in Texas. Most of the "winter" our
>temperatures are not low enough to justify a heat pump.
I believe this statement is wrong. Heat pumps are designed to work
most efficiently in areas where the winter climate is rather moderate.
Once the temperatures get too low below 30ish or so they rely on the
electric resistance element to provide heat. If you have winters where
it doesn't get too cold a heat pump should work very well.
Geothermal heat pumps are one of the most efficient ways to heat and
cool. Theses rely on using underground water rather than air as the
heat source.
Many people don't like heat pumps because they think the air coming
out of the vents feels "cool". The air coming out of a heat pump isn't
as warm as air from say an oil fired furnace. A heat pump relies on
moving a greater volume of air at a lower temperature delta where some
other types of heaters use lower volumes of hotter air.
I like heat pumps for my climate (Virginia Beach, VA) since our
winters are usually fairly mild and I am more concerned about the air
cooling part of it during our hot, muggy summers.
>Local utilities push them.
Because in many areas they are a more energy efficient way to
heat/cool.
>They are highly profitable for them to sell.
>That doesn't make them a wise investment.
I can't speak for the rest of the country but in my area my utility
company doesn't sell heat pumps so I don't see how they profit.
>For really good information contact Florida State University which has a
>department that has done outstanding research on heating and cooling of
>buildings with southern emphasis. I know they have fact sheets on heat
>pumps.
>
>Really take a good hard look at this before spending your money.
I would agree. Research ALL of the options you are considering as a
heat source not just heat pumps!
Tony D. Lowe
wrote:
>Leaving the chauvanism aside, his point is that heat pumps are designed
>for climates where there is a substantial difference during cold weather
>between indoor and outdoor ambient temperatures. Other than a few days a
>year we just don't have that in Texas. Most of the "winter" our
>temperatures are not low enough to justify a heat pump.
This makes no sense. The heat pump doesn't work on the difference in indoor
vs. outdoor ambient temperature. It works on the principle that any air
temperature above absolute zero contains heat, friction from the movement of
molecules; the temperature of the refrigerant used, when compressed and
expanded, is lower than the outside air temperature in all but the most
extreme sub-zero conditions. Therefore, the pump is able to extract heat from
the outside air and deliver it inside; heat always travels in the direction of
the colder object. In the summer, the process is reversed and the heat is
pumped from inside to outside.
If natural gas and electricity were comparable in price, then the heat pump
would be the single most cost effective way to heat your home. The only
reason they are expensive is because electricity generally costs more than
natural gas. If only electricity is available it is definitely the cheapest
form of electric heat.
As a side note: York has started making a natural gas fired heat pump (uses a
small NG engine to drive the compressor) which is up to 40% more efficient in
heating mode than the most efficient NG furnace because it is able to recover
additional heat from the engine. In cooling mode, it is on par with
traditional central air conditioners or heat pumps. And it's cheaper to
operate all year around because of the generally lower cost of NG.
Just my $0.02 worth.
BTW: I use a heat pump now to heat and cool my home.
Tony D. Lowe, The HapMaster
Louisville, KY
hap...@thepoint.net
http://www.thepoint.net/~hapmstr
Tony D. Lowe
Larry Madole
>In article <4h1vtt$c...@masala.cc.uh.edu>, Larry Madole <trak...@interloc.com>
>wrote:
>>Leaving the chauvanism aside, his point is that heat pumps are designed
han a few days a year we just don't have that in Texas. Most of the "winter" our temperatures are not low enough to justify a heat =
pump.
>
>This makes no sense. The heat pump doesn't work on the difference in indoor
"Whew! I am sure glad I didn't say I was an engineer - nobody would ride
my train. I was quoting and maybe misquoting a well known local [Gulf
Coast Texas] builder, college building program director and radio/TV show
guru who is considered to be pretty reliable. It is interesting that
even if one of his programs is sponsored by local electric co. he still
maintains that heat pumps are a bad investment in this area. I may well
have garbled the reasons he gave. The major point I was trying to make
was to research the question and avoid advice from those selling the
units. Now I will go try and read up on heat pumps.
Kyle Harper
>For really good information contact Florida State University which has a
>department that has done outstanding research on heating and cooling of
>buildings with southern emphasis. I know they have fact sheets on heat
>pumps.
>
e (aka, geothermal) heatpumps.
Mike Nickerson
>
> Hi Ya'll,
>
> We are going to build our new home this year and are in the planning
> stages right now. We are building a 1-1/2 story house with about 2800
> square feet of living space. We cannot decide whether to go with a
> conventional heating & cooling system or a heat pump/geothermal system.
> concerned about its efficiency and ability to really keep our house
> cool in summer and warm in winter. Since we live in southeast Texas,
> obviously keeping cool is the bigger concern for us, however, we can
> usually expect two to three weeks of really cold temps each winter.
>
>
> 1. If we go with the heat pump, can we really expect to recoup
> our investment over time due to reduced electricity bills?
>
> (too hot/too cold) that we will not be able to adjust?
>
> needs, or will we need some alternative back-up system?
>
> desire by using a conventional system along with good insulation,
> windows, ceiling fans, system zoning, etc..? P.S. Our 5-acre lot
> is HEAVILY wooded -- plenty of shade.
>
> appreciated. No e-mail please -- just post replies to this group.
>
> Thanks,
>
> Liz Foltz
I would point out that you asked about geothermal heat pumps and note that
all the replies I have seen so far have NOT been about geothermal heat
pumps. I would personally think that especially in your climate, the
geothermal heat pump would be the ideal choice.
It seems your major concern is heating. As far as I know, your only
choices are:
1. Regular central air conditioning. This is an air-to-air heat exchanger
which sits outside in the weather. It will be trying your house and
dumping the excess heat to the outside air which is 100F or so. In
addition, you have to do _something_ for heating.
2. Standard air-source heat pump. Essentially, this is the same as the
central air conditioner but it can also work "backwards" and pull
heat from outside and put it in the house in the winter. Again,
this has to sit outside. I believe that lifetimes of these units are
7-10 years. I think the central air conditioning may be about the
same lifetime since much of the problem is outside weathering.
3. Geothermal heat pump which uses water as the heat sink. This unit
sits inside the house or garage so it is shielded from all the
weather-related aging. In addition, it dumps its heat to a lower
temperature water source. What that temperature is, I don't know.
A good approximation would be to measure the temperature of your
cold water after it runs for several minutes. Since the heat sink is
a lower temperature, the unit will run more efficiently.
Also, if this unit were sized properly, it would do a no-questions-asked
job of keeping the house warm and cool. Our geothermal unit has kept
the house at 70F when outside temperatures were -25F and it has kept
the house at 75F when outside temperatures were 100F+.
So, if you install any sort of air conditioning, you are essentially
getting a "heat pump." The question then is, whether it will also heat
the house and whether it will exchange the heat into air or water.
Mike Nickerson
mi...@boi.hp.com
Kirk Kerekes
Lowe) wrote:
[mucho snippo]
> If only electricity is available it [heat pump] is definitely the cheapest
> form of electric heat.
>
Actually, no. In some reasonably careful tests by the gooberment, radiant
heating panels (Enerjoy were the ones used) tested as being more efficent
than a recent vintage heat pump. The same structure was used for both
tests, and the units were controled by the occupants (IE, a real-world
test). The occupants preferred the heat panels, and the electricity
consumption was lower.
The efficiency difference wasn't much, and seems to have been accounted
for by the mechanical and thermal costs of ductwork. That fan doesn't blow
for free.
Ben Klausner
>>appreciated. No e-mail please -- just post replies to this group.
>>
>>Thanks,
>>
>>Liz Foltz
>>
>bought the heat pump yet! In the words of one building expert guru who
>is on the radio down here in Space City: "Heat pumps were designed by
>Yankees, built by Yankees, sold by Yankees and by damn, they should use
>them and leave us alone".
>
>for climates where there is a substantial difference during cold weather
>year we just don't have that in Texas. Most of the "winter" our
Congratulations. You have it exactly backwards! heat pumps work very well
in southern climates where the heaing load is light. I have an older one,
and it's perfectly happy sown to ~20F. Then it has to start using auxilary
heat. In my case it's electric auxilary, but if I had gas I'd go that
route.
Much more practical in the south than having an entirely seperate A/C and
heater.
--
-----------------------------------------------------------------------------
Ben Klausner, N5DJL | Klein Bottle for sale.
klau...@netcom.com | Inquire within.
Austin, TX |
Phil Ngai
Mike Nickerson <mi...@boi.hp.com> wrote:
>So, if you install any sort of air conditioning, you are essentially
>getting a "heat pump." The question then is, whether it will also heat
>the house and whether it will exchange the heat into air or water.
Gee, Mike, you left out a minor issue. Is geothermal economical over
air-source? Putting your heat transfer loop in the soil can be
expensive. Doesn't it usually add about $6-10K to the cost of the
system?
I'd agree that it's probably the right choice, but I don't like to see
important factors like this ignored.
One thing that I keep wondering about is why no one seems to build air
conditioners that use a swimming pool for cooling the condensor.
Especially in Florida...
--
In ten years, Apple Computer has gone from a company which talked
about how great their computers were to a company which talks
about how great their computers were 10 years ago.
Phil Ngai
Edward Rice <ehr...@his.com> wrote:
<In article <4hi68r$l...@neutra.mv.us.adobe.com>,
<pn...@adobe.com (Phil Ngai) wrote:
<
< > One thing that I keep wondering about is why no one seems to build air
< > conditioners that use a swimming pool for cooling the condensor.
< > Especially in Florida...
<
<much evaporative cooling (humid weather in Florida, right?) and without a
<fresh supply of water (most pools operate on a closed water system), you'd
<just keep warming up the pool until the air conditioning wasn't working
<much and/or the pool was boiling. No big win.
The sun shines on most pools all day long, delivering 500 to 1000 watts
per square foot. Does your swimming pool boil?
How many kilowatts of heat does your A/C deliver? Quick and dirty
calculation is to take the electricity drawn and multiply by 3. So a 5
kilowatt system would move 15 kilowatts. (don't confuse the Coefficient
of Performance with the bastard unit SEER, which mixes KW and BTUs.)
If we consider a small pool that's 15 feet by 30 feet, or 450 square
feet and say that only 250 watts/square foot of solar heat is absorbed,
that's 112.5 kilowatts of solar heat. Gee, guess there must be some
cooling mechanism operating, and the 14% additional load of an AC
condensor not likely to overwhelm it.
Having said all that, I have to admit I like warm swimming pools...
David Lesher
>The sun shines on most pools all day long, delivering 500 to 1000 watts
>per square foot. Does your swimming pool boil?
Plus, in Critter Florida, everyone has a screened pool enclosure,
shading it so it is NOT totally in the sun.
But you'd need a Monel/Stainless heta exchanger...
--
A host is a host from coast to coast.................wb8foz@nrk.com
& no one will talk to a host that's close...........(v)301 56 LINUX
Unless the host (that isn't close).........................pob 1433
is busy, hung or dead........vr vr vr vr.................20915-1433
RICKY D VAN MATRE
Believe it or not, it kinda boils. Evaporation in NM off pools is
something like 100 inches per year!
Edward Rice
pn...@adobe.com (Phil Ngai) wrote:
> In article <AD63D50E9...@ehrice.his.com>,
> Edward Rice <ehr...@his.com> wrote:
> <In article <4hi68r$l...@neutra.mv.us.adobe.com>,
> <pn...@adobe.com (Phil Ngai) wrote:
> <
> < > One thing that I keep wondering about is why no one seems to build
air
> < > conditioners that use a swimming pool for cooling the condensor.
> < > Especially in Florida...
> <
> <Because the water in the pool would get so darned hot, possibly?
Without
> <much evaporative cooling (humid weather in Florida, right?) and without
a
> <fresh supply of water (most pools operate on a closed water system),
you'd
> <just keep warming up the pool until the air conditioning wasn't working
> <much and/or the pool was boiling. No big win.
>
> The sun shines on most pools all day long, delivering 500 to 1000 watts
> per square foot. Does your swimming pool boil?
Well, okay, "boil" was an exaggeration.
> How many kilowatts of heat does your A/C deliver? Quick and dirty
> calculation is to take the electricity drawn and multiply by 3. So a 5
> kilowatt system would move 15 kilowatts. (don't confuse the Coefficient
> of Performance with the bastard unit SEER, which mixes KW and BTUs.)
>
> If we consider a small pool that's 15 feet by 30 feet, or 450 square
> feet and say that only 250 watts/square foot of solar heat is absorbed,
> that's 112.5 kilowatts of solar heat. Gee, guess there must be some
> cooling mechanism operating, and the 14% additional load of an AC
> condensor not likely to overwhelm it.
Consider, though, that the heat coming in from the sun (and other sources)
is balanced (roughly) by the heat loss from radiation (and other methods),
and that most pools /do/ heat up significantly in mid-summer, especially
when it's humid in the day and the nights are cloudy. (Virginia is a LOT
like that for several months a year.) The thermostasis reached without the
air conditioning load being passed to the pool is often PLENTY warm enough,
or even too warm (ours went well into the 80's -- no longer a "refreshing"
swimming place), and adding even a modest 14% additional heat, day AND
night, could well turn the pool into a hot tub.
> Having said all that, I have to admit I like warm swimming pools...
Me, too. But we considered dumping /ice/ in ours, in August. (20x40,
35,000 gallons, and we did not use the cover on a daily basis in
mid-summer)
P. Yannone
>In article <4hi68r$l...@neutra.mv.us.adobe.com>,
>pn...@adobe.com (Phil Ngai) wrote:
> > One thing that I keep wondering about is why no one seems to build air
> > conditioners that use a swimming pool for cooling the condensor.
> > Especially in Florida...
>Because the water in the pool would get so darned hot, possibly? Without
>much evaporative cooling (humid weather in Florida, right?) and without a
>fresh supply of water (most pools operate on a closed water system), you'd
>just keep warming up the pool until the air conditioning wasn't working
>much and/or the pool was boiling. No big win.
Rube Goldberg would have suggested adding a large fountain to the
pool.
Edward Rice
yannone@acm (P. Yannone) wrote:
I've seen /commercial/ installations that do this -- to reduce the load on
their cooling towers, they run water areas (shallow ones) near the
building, with a lot of fountains and splash-basins. I don't know how that
compares in efficiency with a cooling tower like most buildings have.
pwate...@gmail.com
> Hi Ya'll,
>
> We are going to build our new home this year and are in the planning
> stages right now. We are building a 1-1/2 story house with about 2800
> square feet of living space. We cannot decide whether to go with a
> conventional heating & cooling system or a heat pump/geothermal system.
> We like the idea of the more environmentally friendly heat pump, but are
> concerned about its efficiency and ability to really keep our house
> cool in summer and warm in winter. Since we live in southeast Texas,
> obviously keeping cool is the bigger concern for us, however, we can
> usually expect two to three weeks of really cold temps each winter.
>
> Questions:
>
> 1. If we go with the heat pump, can we really expect to recoup
> our investment over time due to reduced electricity bills?
>
> 2. Can there be temperature control problems with the system
> (too hot/too cold) that we will not be able to adjust?
>
> 3. Is the heat pump system adequate for all heating and cooling
> needs, or will we need some alternative back-up system?
>
> 4. Would we be able to achieve the cost savings and efficiency we
> desire by using a conventional system along with good insulation,
> windows, ceiling fans, system zoning, etc..? P.S. Our 5-acre lot
> is HEAVILY wooded -- plenty of shade.
>
> appreciated. No e-mail please -- just post replies to this group.
>
> Thanks,
>
> Liz Foltz
I quite enjoyed reading it, you’re a great author.I will remember to bookmark your blog and will often come back sometime soon.
I want to encourage you continue your great work.
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Bob F
SPAM to.