are air source heat pumps a threat to geothermal heat pump suppliers

8/10/2019 Are Air Source Heat Pumps a Threat to Geothermal Heat Pump Suppliers

1/10

The World's #1 Renewable Energy Network for News, Information &

Companies

Sign In or Regis

Thursday, February 13, 2014

Are Air Source Heat Pumps a Threat toGeothermal Heat Pump Suppliers?

Tom Konrad, Contributor

February 06, 2014 | 13 Comments

Last year, geothermal heat pump (GHP) manufacturers introduced new heat

pumps with break-through efficiency based on variable-speed compressor

technology. These manufacturers include Waterfurnace Renewable Energy

(TSX:WFI, OTC:WFIFF) and ClimateMaster, a division of LSB Industries(NYSE:LXU).

Air Source and Ground Source

Variable speed compressortechnology was not restricted to geothermal heat

pumps (also known as ground source heat pumps or geoexchange): It had

first found its way into what are often considered ground sources poor

cousins: air source heat pumps (ASHP).

Both types of heat pumps use a refrigeration cycle to draw heat from the

outside in winter to heat a building, and pull heat from the inside to cool it insummer. GHPs use large loops of buried tubing to exchange heat with the

ground, while ASHPs use an above-ground fan and heat exchanger

assembly similar to the evaporator on a traditional whole house air

conditioner (see photo).

Before the advent of variable speed compressor technology, air source heat

pumps were only suitable in mild climates because heating performance fell

off rapidly at temperatures below 40F (see chart), while the near constant

temperature of the earth allowed GHPs to operate efficiently in any climate.

Email Share LinkedIn

Facebook Tweet 5

Print 0 0

7 7Like

FOLLOW CONTACT

Recent Activity

Network Users

Articles

Comments

Contact

Tom Konrad

Tom Konrad is a

private money

manager and

freelance writer focused on Peak

and Climate Change as investme

themes. He manages portfolios fo

individual clients and am co-

manager of the JPS Green

Economy Fund

(http://jpsgreeneconomyfund.com

IMAGE GALLERY

Home Solar Wind Geothermal Bio Hydro Storage Jobs Companies Webcasts

White Papers Magazines Awards
http://www.renewableenergyworld.com/rea/u/TomKonrad/commentshttp://www.renewableenergyworld.com/rea/u/TomKonrad/articleshttp://www.renewableenergyworld.com/rea/u/TomKonradhttp://www.renewableenergyworld.com/rea/u/TomKonradhttp://www.renewableenergyworld.com/rea/white-papershttp://www.renewableenergyworld.com/rea/magazinehttp://www.renewableenergyworld.com/rea/awardshttp://www.renewableenergyworld.com/rea/white-papershttp://www.renewableenergyworld.com/rea/magazinehttp://www.renewableenergyworld.com/rea/awardshttp://www.renewableenergyworld.com/rea/homehttp://www.renewableenergyworld.com/rea/home/solar-energyhttp://www.renewableenergyworld.com/rea/homehttp://www.renewableenergyworld.com/rea/homehttp://www.renewableenergyworld.com/rea/account/user/registerhttp://www.renewableenergyworld.com/rea/u/TomKonradhttp://www.renewableenergyworld.com/rea/u/TomKonradhttp://www.renewableenergyworld.com/rea/u/TomKonrad/contacthttp://www.renewableenergyworld.com/rea/awardshttp://www.renewableenergyworld.com/rea/magazinehttp://www.renewableenergyworld.com/rea/white-papershttp://www.renewableenergyworld.com/rea/events/webcasthttp://www.renewableenergyworld.com/rea/companies/searchhttp://www.renewableenergyworld.com/rea/careershttp://www.renewableenergyworld.com/rea/home/energy-storagehttp://www.renewableenergyworld.com/rea/home/hydropowerhttp://www.renewableenergyworld.com/rea/home/bioenergyhttp://www.renewableenergyworld.com/rea/home/geothermal-energyhttp://www.renewableenergyworld.com/rea/home/wind-powerhttp://www.renewableenergyworld.com/rea/home/solar-energyhttp://www.renewableenergyworld.com/rea/homehttp://www.renewableenergyworld.com/rea/images/are-air-source-heat-pumps-a-threat-to-geothermal-heat-pump-suppliers/83013http://www.renewableenergyworld.com/rea/u/TomKonradhttp://www.renewableenergyworld.com/rea/u/TomKonradhttp://www.renewableenergyworld.com/rea/u/TomKonrad/contacthttp://www.renewableenergyworld.com/rea/u/TomKonrad/commentshttp://www.renewableenergyworld.com/rea/u/TomKonrad/articleshttp://www.renewableenergyworld.com/rea/u/TomKonrad/network/usershttp://www.renewableenergyworld.com/rea/u/TomKonradhttp://www.renewableenergyworld.com/rea/u/TomKonrad/contacthttp://www.renewableenergyworld.com/rea/u/TomKonradhttp://www.renewableenergyworld.com/rea/news/print/article/2014/02/are-air-source-heat-pumps-a-threat-to-geothermal-heat-pump-suppliershttp://twitter.com/search?q=http%3A%2F%2Fwww.renewableenergyworld.com%2Frea%2Fnews%2Farticle%2F2014%2F02%2Fare-air-source-heat-pumps-a-threat-to-geothermal-heat-pump-suppliershttps://twitter.com/intent/tweet?original_referer=http%3A%2F%2Fwww.renewableenergyworld.com%2Frea%2Fnews%2Farticle%2F2014%2F02%2Fare-air-source-heat-pumps-a-threat-to-geothermal-heat-pump-suppliers%3Fcmpid%3DGeoNL-Thursday-February13-2014&text=Are%20Air%20Source%20Heat%20Pumps%20a%20Threat%20to%20Geothermal%20Heat%20Pump%20Suppliers%3F&tw_p=tweetbutton&url=http%3A%2F%2Fwww.renewableenergyworld.com%2Frea%2Fnews%2Farticle%2F2014%2F02%2Fare-air-source-heat-pumps-a-threat-to-geothermal-heat-pump-suppliershttp://en.wikipedia.org/wiki/Heat_pump_and_refrigeration_cyclehttp://en.wikipedia.org/wiki/Air_source_heat_pumpshttp://www.renewableenergyworld.com/rea/u/TomKonradhttp://www.renewableenergyworld.com/rea/homehttp://www.renewableenergyworld.com/rea/account/user/registerhttp://www.renewableenergyworld.com/rea/account/login


2/10

Now, the most efficient ASHP models only begin to lose significant heating

efficiency at 25F and still maintain significant heating capacity at 0F, a

change which has made them practical in most of the United States.

With variable speed technology, these units are now suitable for heating

climates where the temperature occasionally falls below 0F, although they

may require some form of back up heat. The improved technology has

meanwhile made the efficiency of the best air source heat pumps equivalent

to that of many GHPs, especially when used in less extreme climates.

Although even the best ASHPs are still much less efficient than the best

GHPs, the cost savings from dispensing with the ground loop and (in some

cases) air ducts mean that ASHPs are an economic option in many cases

where GHPs or conventional heating were previously the only viable options.

Air Source Heat Pumps In Practice

In a recent article, Marc Rosenbaum, director of engineering at South

Mountain Company on Marthas Vineyard in Massachusetts, says that nearly

every building he has worked on for the last several years has used ASHPs

almost exclusively.

There are caveats, of course. Rosenbaum works exclusively on very high

performance, super-insulated buildings. He also teaches a course on

designing net-zero energy buildings. And even with super-insulation, he

uses other heat sources in larger buildings.

Heating performance of a variable speed air-source heat pump (in this case

Mitsubishi hyper-heat) compared to traditional models. Source: Mitsubishi

Im in the process of my own retrofit of a 1930 farmhouse which I bought two

years ago. Ive spray-foamed the basement and attic as well as improved

the overall building envelope with air sealing, and expect to continue to make

envelope improvements going forward. I was able to have four Mitsubishi

ASHPs installed in the most important rooms without having to give up

interior space for ducting. This cost me about $12,000 after utility and tax

rebates and is saving me about $1,000 to $2,000 in annual energy costs. A

To register for our free e-

Newsletters, create your free

account here:

Stay

Connected

GO

EDITORS' PICKS

US CongressionalAction Could Help

Advance Energy

Storage Technologies

Top Ten PV

Manufacturers from

2000 to Present: A Pictorial

Retrospective

Designing and

Achieving Geotherma

Power Plant

Performance with Confidence

Cleantech's Investme

Cycle: Don't Worry,

Think Bigger
http://www.renewableenergyworld.com/rea/news/article/2014/01/trident-in-marine-control-technology-optimisation-breakthoughhttp://www.renewableenergyworld.com/rea/news/article/2014/01/cleantechs-investment-cycle-dont-worry-think-biggerhttp://www.renewableenergyworld.com/rea/news/article/2014/01/designing-and-achieving-geothermal-power-plant-performance-with-confidencehttp://www.renewableenergyworld.com/rea/news/article/2014/01/top-ten-pv-manufacturers-from-2000-to-present-a-pictorial-retrospectivehttp://www.renewableenergyworld.com/rea/news/article/2014/01/us-congressional-action-could-help-advance-energy-storage-technologieshttp://www.facebook.com/pages/RenewableEnergyWorldcom/70072212355http://www.linkedin.com/groups?gid=2121068http://twitter.com/reworldhttps://plus.google.com/113380590810694768057/postshttp://www.renewableenergyworld.com/rea/news/syndicatehttp://www.renewableenergyworld.com/rea/images/are-air-source-heat-pumps-a-threat-to-geothermal-heat-pump-suppliers/83013http://nesea.cammpus.com/courses/zero-net-energy-homes--onlinehttp://www.greenbuildingadvisor.com/blogs/dept/guest-blogs/minisplit-heat-pumps-and-zero-net-energy-homes


3/10

comparable GHP system would have saved me $2,000 to $3,000 annually,

but would have cost about $30,000 after utility and tax rebates. The extra

$1,000 annual savings did not seem to me to justify the extra $20,000 in

cost, given that I expect to sell in less than ten years, and both systems

significantly boosted the homes value by adding air conditioning.

Alternative Energy Specialist Scott Lankhorst of Advanced Radiant Design in

Stone Ridge, New York, says that he does not see ASHPs and GHPs as

direct competitors. GHPs are typically only installed on homes of a

minimum square footage, with multiple rooms that need direct heat delivery.

This agrees with Rosenbaums finding that Compact superinsulated homes

in [many] climates can often be heated with a single zone unit in the

main space. As long as the doors to other rooms remain open, the

temperatures in those rooms will usually be within 2F of the [main space]."

Air Source Heat Pump Suppliers

Lankhorst says that the most efficient air source units are from Mitsubishi

(OTC:MSBHY) and Fujitsu. The latter are easier to install, but the Mitsubishi

systems can work with a Honeywell (NYSE:HON) wireless programmablethermostat. This can be accessed via the web or mobile devices, which is

useful in a building with multiple units. After discovering the limited

programability of the factory controller for my Mitsubishi units, I installed the

Honeywell thermostats in addition to a thermostat for my boiler which I now

control them all through the same interface.

The Honeywell smartphone app for controlling my four Mitsubishi ASHPs and

oil-fired boiler.

Conclusion

Trident in Marine

Control Technology

Optimisation Breakthough

MOST COMMENTED

13Are Air Source Heat Pump

a Threat to Geothermal He

Pump Suppliers?

8 The Road to Renewable

Energy in Alberta, Canada

7 Renewables Provide 15%

Supply During California

Emergency Time to Go100% Renewable?

7 Renewable Energy Provid

37% of All New US Electric

Generating Capacity in 20

7 Its Cold and My Car is

Buried in Snow; Is Global

Warming Really Happenin
http://www.renewableenergyworld.com/rea/news/article/2014/01/its-cold-and-my-car-is-buried-in-snow-is-global-warming-really-happeninghttp://www.renewableenergyworld.com/rea/news/article/2014/01/renewable-energy-provides-37-of-all-new-us-electrical-generating-capacity-in-2013http://www.renewableenergyworld.com/rea/news/article/2014/02/renewables-provide-15-of-supply-during-california-emergency-time-to-go-100-renewablehttp://www.renewableenergyworld.com/rea/news/article/2014/01/the-road-to-renewable-energy-in-alberta-canadahttp://www.renewableenergyworld.com/rea/news/article/2014/02/are-air-source-heat-pumps-a-threat-to-geothermal-heat-pump-suppliershttp://www.renewableenergyworld.com/rea/news/article/2014/01/trident-in-marine-control-technology-optimisation-breakthoughhttp://cleanenergywonk.com/2013/04/16/adding-a-programmable-thermostat-to-mitsubishi-mr-slim-heat-pumps/http://www.altenergystocks.com/comm/content/honeywell/http://www.forbes.com/companies/fujitsu/


4/10

While variable speed air source heat pumps can be competitive with

geothermal heat pumps in retrofit situations and smaller, better insulated

buildings and less extreme climates, GHPs remain the most efficient way to

heat and cool a building.

If super-insulated, small buildings ever become the standard way to build a

home, geothermal heat pump manufacturers such as Waterfurnace and LSB

may have something to fear from air source heat pumps. Fortunately for

GHP manufacturers, but unfortunately for the rest of us, that day is still a

long way off.

DISCLOSURE: Long LXU, WFIFF

This article was first published on the author's Green Stocks blog on

Forbes.com on January 14th and AltEnergy Stocks and was republished with

permission.

DISCLAIMER: Past performance is not a guarantee or a reliable indicator of

future results. This article contains the current opinions of the author and

such opinions are subject to change without notice. This article has beendistributed for informational purposes only. Forecasts, estimates, and certain

information contained herein should not be considered as investment advice

or a recommendation of any particular security, strategy or investment

product. Information contained herein has been obtained from sources

believed to be reliable, but not guaranteed.

Read More Geothermal Energy News Here

13 COMMENTS REGISTER TO COMMENT

DENNIS HOUGHTON

February 10, 2014

Back in the bad ole days, @40 years, an engineer might greatly

over-design a HVAC system just to guarantee it would work in

the absolute worst case conditions. Electrical power was cheap

(too cheap to meter) and equipment and skilled labor were

relatively inexpensive. Reputation was more important than

cost.

Conditions are very different today. Reputations are built upon

cost control through energy management.

Resistance heat is a wise substitute for gross over-design in

any installation, particularly at the residential level.

Resistance heating can be augmented or even replaced by

alternate heat sources.
http://www.renewableenergyworld.com/rea/u/dennis-houghton-41194http://www.renewableenergyworld.com/rea/u/dennis-houghton-41194http://www.renewableenergyworld.com/rea/account/user/registerhttp://www.renewableenergyworld.com/rea/home/geothermal-energyhttp://www.altenergystocks.com/archives/2014/01/are_air_source_heat_pumps_a_threat_to_geothermal_heat_pump_suppliers.htmlhttp://www.forbes.com/sites/tomkonrad/http://www.forbes.com/sites/tomkonrad/2014/01/15/are-air-source-heat-pumps-a-threat-to-geothermal-heat-pump-suppliers/


5/10

Living "off-grid" with a dependency upon a large electrical

machine poses a small irony in any case.

WARREN MCKENNA

February 10, 2014

Bob--Thanks for coming clean on your resistance heat use.

Unless you are talking about commercial systems it is common

for residential systems to utilize the resistance heat for normal

operation. Once you set that demand the power company has

to have the capacity in place to serve you. Your transformer

size is larger, your service is larger, your service panel is larger,

and that is primarily due to the 15 kW to 20 kW of resistance

heat that might hit the electric system. The point i'm trying to

make is that if you had gas backup then the power company

and you wouldn't have to invest in the capacity to serve that

resistance load for the few times in a hard winter that it mightget used. Someone has to invest in the electric capacity to

serve that potential load. The newer heat-pumps that use gas

have less of an impact on the grid as does your GSHP and they

cost 1/2 as much to install. Try going off grid with your GSHP

and its resistance heat and you will soon find its not possible.

BOB FREESTON

February 9, 2014

Warren--I have a resistive element in my GSHP which

supplements in the coldest weather. It is on infrequently on long

heat runs. I have an old farm house (150 years old) added on

to a number of times. I've upgraded insulation from poor to

mediocre. A modern building with reasonable insulation should

hardly use the supplement at all. It should still be included for

emergency back up. My electric is roughly 40% grid hydro and

most of the rest is wind I pay extra for. I also have a small solar

system on site. There are numerous solutions available, with

more to come.

WARREN MCKENNA

February 8, 2014

I might add Bob that these are Iowa winters. I wish it weren't

true but it is and it is by design.

These systems do little to discourage the building of new coal
http://www.renewableenergyworld.com/rea/u/warren-mckenna-25172http://www.renewableenergyworld.com/rea/u/warren-mckenna-25172http://www.renewableenergyworld.com/rea/u/bob-freeston-133871http://www.renewableenergyworld.com/rea/u/bob-freeston-133871http://www.renewableenergyworld.com/rea/u/warren-mckenna-25172http://www.renewableenergyworld.com/rea/u/warren-mckenna-25172


6/10

and nuclear plants. In fact they may increase the need. "The

Red Queen Dilemma"

WARREN MCKENNA

February 8, 2014

@Bob, I'm not talking about poorly designed systems. We

meter over 30+ residential systems, including demand and

kWhr energy readings for every day. They all at some point

during the winter months utilize their resistance heat elements.

Some of this depends on consumer use of the thermostat. The

fact is, to be cost competitive designers and installers rely on

the resistive heat not only as backup but as part of the system

performance. If you don't believe me then every system you

install should have the resistive coils un-hooked and you might

find how your systems are designed.

BOB FREESTON

February 7, 2014

Ground Source Heat Pumps can use either closed or open

loops. Warren's comment about a closed loop loosing

effectiveness late in winter indicates a poorly designed system.

Also this would not occur in an open loop system. A standing

column should also avoid this. Florida and data center systemsneed extra closed loop lengths because of the heavy

domination of cooling loads. Installation costs are sometimes

lowered by using existing wells, my system is based on this, or

ponds or lakes. Desuperheaters in the system now can supply

year round hot water on a separate compressor loop. The

water is almost free in the summer because it's being removed

from the house. In this region (upstate N Y) new houses are

going in as net zero with super insulation, PV on the roof driving

small GSHP loads. A 9 house development I'm familiar with

used insulated concrete forms on basement, first floor and up

second floor gable ends then blown cellulose or foam (I forget

which) for an R50 roof. The PV drives a Water Furnace 3 ton

system (their smallest) around 2 tons on variable speed.

JOHN DANGELO

February 7, 2014

Do you realize that many people are offering these heat pumps
http://www.renewableenergyworld.com/rea/u/john-dangelo-175629http://www.renewableenergyworld.com/rea/u/john-dangelo-175629http://www.renewableenergyworld.com/rea/u/bob-freeston-133871http://www.renewableenergyworld.com/rea/u/bob-freeston-133871http://www.renewableenergyworld.com/rea/u/warren-mckenna-25172http://www.renewableenergyworld.com/rea/u/warren-mckenna-25172


7/10

coupled with solar modules?

Typically these system heat about 600 sq feet. This is a game

changer. You can install a heat pump that cools and heat a

space all run off solar energy. In many parts of the country this

will work quite well and not need a back up heat source,

especially with super insulated homes which should become

standard in the industry anyways! One company is coupling the

system to a battery bank which will provide power during a

power outage and yet still draw from the utility when needed.

Yes we do need to get off fossil fuels. Install a wood pellet stove

or a wood stove as a back up for the weather extremes. Cost

per MMBTU is generally my top consideration for heating and

cooling. Also when people talk GWHP they fail to mention that

the lactic bills god sup and the natural gas bill goes down. But

on balance a GWHP is at best an energy efficient measure but

at the end of the day for the money spend really does not save

as much as GWHP people claim.

I had a quote a few years back for a GWHP for my 1600 sq foot

house and it was about $30,000. I installed a solar hot water

heating system and I use a wood pellet stove as my back up.

The savings form the solar pays for the pellets so I truly heat

for free.

WARREN MCKENNA

February 7, 2014

The problem with current residential GSHP's is the electric heat

used to supplement and/or backup the units. Near the end of a

hard winter, due to ground saturation, they may be running

almost entirely on the electric resistance a majority of the time.

This contributes to peak demand and decreases utility load

factors. The best of both worlds would be a GSHP with Gas for

the supplemental and backup heat. I have done the research

however I wonder if the newer HP with Gas actually offers a

lower overall carbon footprint than a GSHP with resistance

elements would.

V. BRUCE STENSWICK

February 7, 2014

In response to Mr. Kelly, I am not certain that GSHPs are any

more efficient. You would have to monitor the temperature of
http://www.renewableenergyworld.com/rea/u/v-bruce-stenswick-62270http://www.renewableenergyworld.com/rea/u/v-bruce-stenswick-62270http://www.renewableenergyworld.com/rea/u/warren-mckenna-25172http://www.renewableenergyworld.com/rea/u/warren-mckenna-25172


8/10


9/10

Add Your Comments

To add your comments you must sign-in or create a free account.

DENNIS HOUGHTON

February 6, 2014

A decade ago, electric motors consumed almost 60% of all the

electrical power produced in the world. The efficiencies

introduced by rapid improvement and drop in cost in Variable

Frequency Drives (VFD) have reduced that number to less than

50% today. Datacenters have taken up some of that lost

consumption and the utilities are grateful.

Variable Motor applications such as fans, pumps and

compressors can operate properly with as much as a 50% drop

in power consumption. Twenty years ago the energy would

have been wasted with valves and dampers, now it is simply

not used. System performance was usually improved,

especially in HVAC and water pumping systems. Ground

source heat pumps benefit from the same VFD technology so it

is not really a competitive edge for air source systems. Total

system cost remains the air source systems competitive edge.

JEFF KELLY

February 6, 2014

Yea, but what about summer? The real efficiency of GSHP is

being able to reject heat to a 70F ground temperature rather

than a 100F air temperature.

Perhaps the general point of this article is that improvements in

ASHP's have taken some of the thrunder away from GSHP's.

Create an Account! Sign-In

TOTAL ACCESS PARTNERS Growing Your Business?Learn More about To

Acce
http://www.renewableenergyworld.com/rea/corporate/advertising/totalaccesshttp://www.renewableenergyworld.com/rea/companies/searchhttp://www.renewableenergyworld.com/rea/account/loginhttp://www.renewableenergyworld.com/rea/account/user/registerhttp://www.renewableenergyworld.com/rea/u/jeff-kelly-146257http://www.renewableenergyworld.com/rea/u/jeff-kelly-146257http://www.renewableenergyworld.com/rea/u/dennis-houghton-41194http://www.renewableenergyworld.com/rea/u/dennis-houghton-41194


10/10

News

Renewable

Energy

Solar EnergyWind Energy

Bioenergy

Geothermal

Energy

Hydro Power

Blogs

Video

Finance

Resources

Companies

Products

Careers

Events

Webcasts

White Papers

Magazines

Press Releases

e-Newsletters

Company

About Us

Our Team

Contact Us

Advertising &

Services

Privacy Policy

Terms &

Conditions

Site Map

Network Partners - Magazines

Hydro Review Magazine

Hydro Review Worldwide Magazine

Renewable Energy World Magazine

Network Partners - Events

Power-Gen International

Renewable Energy World Conference & Expo North Americ

Renewable Energy World Conference & Expo Europe

Renewable Energy World Conference & Expo Asia

Renewable Energy World Conference & Expo Africa

Renewable Energy World Conference & Expo India

HydroVision International

HydroVision Brazil

HydroVision India

HydroVision Russia

Copyright 1999-2014 RenewableEnergyWorld.com- All rights reserv

RenewableEnergyWorld.com - World's #1 Renewable Energy Network for news & Informa
http://www.renewableenergyworld.com/rea/homehttp://www.hydrovision-russia.com/en_GB/index.htmlhttp://www.hydrovisionindia.com/index.htmlhttp://www.hydrovisionbrasil.com/en/index.htmlhttp://www.hydroevent.com/index.htmlhttp://www.renewableenergyworldindia.com/index.htmlhttp://www.powergenafrica.com/index.htmlhttp://www.renewableenergyworld-asia.com/index.html/http://www.renewableenergyworld-europe.com/index.htmlhttp://www.renewableenergyworld-events.com/index.htmlhttp://www.renewableenergyworld-events.com/solar-power-gen.htmlhttp://www.renewableenergyworld.com/rea/magazine/renewable-energy-world/archiveshttp://www.renewableenergyworld.com/rea/magazine/hydro-review-worldwide/archiveshttp://www.renewableenergyworld.com/rea/magazine/hydro-review/archiveshttp://www.renewableenergyworld.com/rea/sitemaphttp://www.renewableenergyworld.com/rea/corporate/termshttp://www.renewableenergyworld.com/rea/corporate/privacyhttp://www.renewableenergyworld.com/rea/corporate/advertisinghttp://www.renewableenergyworld.com/rea/corporate/contactformhttp://www.renewableenergyworld.com/rea/corporate/contacthttp://www.renewableenergyworld.com/rea/corporate/abouthttp://www.facebook.com/pages/RenewableEnergyWorldcom/70072212355http://www.linkedin.com/groups?gid=2121068http://twitter.com/reworldhttps://plus.google.com/113380590810694768057/postshttp://www.renewableenergyworld.com/rea/news/syndicatehttp://www.renewableenergyworld.com/rea/news/newslettershttp://www.renewableenergyworld.com/rea/news/press-releasehttp://www.renewableenergyworld.com/rea/magazinehttp://www.renewableenergyworld.com/rea/white-papershttp://www.renewableenergyworld.com/rea/events/webcasthttp://www.renewableenergyworld.com/rea/eventshttp://www.renewableenergyworld.com/rea/careershttp://www.renewableenergyworld.com/rea/productshttp://www.renewableenergyworld.com/rea/companies/searchhttp://finance.renewableenergyworld.com/pennwell.renewableenergy/quote?Symbol=$REWhttp://www.renewableenergyworld.com/rea/videohttp://www.renewableenergyworld.com/rea/bloghttp://www.renewableenergyworld.com/rea/home/hydropowerhttp://www.renewableenergyworld.com/rea/home/geothermal-energyhttp://www.renewableenergyworld.com/rea/home/bioenergyhttp://www.renewableenergyworld.com/rea/home/wind-powerhttp://www.renewableenergyworld.com/rea/home/solar-energyhttp://www.renewableenergyworld.com/rea/homehttp://www.renewableenergyworld.com/rea/companies/geothermal-resources-councilhttp://www.renewableenergyworld.com/rea/companies/naes-corporationhttp://www.renewableenergyworld.com/rea/companies/geothermal-energy-association-4102http://www.renewableenergyworld.com/rea/companies/admirals-bankhttp://www.renewableenergyworld.com/rea/companies/ambient-technologies-inchttp://www.renewableenergyworld.com/rea/companies/cleanedisonhttp://www.renewableenergyworld.com/rea/companies/enerquiphttp://www.renewableenergyworld.com/rea/companies/maritime-geothermal

are air source heat pumps a threat to geothermal heat pump suppliers

Documents