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-   -   Heat pump or high efficiency furnace (http://www.diychatroom.com/f17/heat-pump-high-efficiency-furnace-52902/)

moisheh 09-13-2009 08:48 AM

Heat pump or high efficiency furnace
 
We have purchased a timber frame home in the country. This home is in the Canadaina prairies where it does get very cold. The home has very high heating costs. But it is over 1900 sq. ft., high ceilings and a heated attached double garage. Presently it has a 9 year old mid efficiency gas furnace, no A/C and some in floor radiant heat. I had a heating guy look at the setup. I was thinking of geo thermal heat, There are government grants available to cover some of the costs. He was against the geothermal for the following reasons: The lots is heavily treed and he would have to rip out a lot of trees, The heat pump unit is large and would take up the entire utility room, very expensive with a slow payback. He recommended a high efficiency furnace

I doubted his comments. I thought that the $ I would spend on a new furnace and AC would be better spent towards a geo thermal system. The new furnace and AC would be at least $6000.

Appreciate any input.

Moisheh

yuri 09-13-2009 09:18 AM

Where exactly do you live? I can tell you lots of info about geothermal. They run anywhere from $20-25,000 installed in Manitoba. They also need some electric supplemental strip heaters and have other issues like any type of heat pump.

moisheh 09-13-2009 11:11 AM

Yuri:

I am very close to you. R.M. of La Broquerie. If your $25,000 is a good guess I wonder about the economics. I know that Hydro has some grants as well as the Fed but the payback would be a very long time. In our area with the cold winters I also wonder if you would get much out of the system in January without electrical backup. This house has a very high ceiling and lots of open area. Hard to heat. I also wonder if the heat pump would put out enough AC in the summer without an auxulliary compressor. Most of the systems I have heard of were done when the house was new. Less costly. I would appreciate any help.

Moisheh

beenthere 09-13-2009 12:33 PM

Yuri. How is the pay back in your area.

Down here. Its not good, if you aren't building a big house. And plan to live there for 30 or more years.

yuri 09-13-2009 12:58 PM

The payback is very long and there is a list of pro's and mostly con's I will give Moisheh. In the average house they will save about $400/yr vs a high efficiency natural gas furnace, a study done by Mb Hydro:http://www.hydro.mb.ca/your_home/hom...?WT.mc_id=2815

What type of gas are you using? Propane or Natural Gas? Your contractor is correct. The unit is large, needs extra large return ducts and it takes a heck of a lot of pipe and wells to heat a house as large as yours. You will need to use additional electric supplemental heaters in our -30 and colder weather and it would be cheaper at that point to use the high efficiency furnace. If you save $500/yr it would take forever to pay it off and you WILL have some EXPENSIVE repairs on it in that time which will eatup your savings. I would recommend a 95% efficient furnace with an ECM motor and run the fan all the time for circulation (only uses 80Watts). I like the Geothermal concept if you are a truly "Green" person but it is not that cost effective yet. These are my opinions only and I am sure the Geo guys may not like them. There are other issues if you want the rest of my views.

dac122 09-14-2009 07:49 AM

Have you priced out a furnace with and without an air source heat pump? What about some alternatives such as pellets, wood or coal? Post your electric rates including taxes and your natural gas (or propane) price/gal, and we can give you some idea of what might work for you.

Yoyizit 09-14-2009 12:36 PM

Or better insulation.

grifzila 05-04-2010 08:04 PM

Geothermal or Not!
 
To echo some previous advice - Geothermal is not the most reliable for the average homeowner. There are few reliable installers. The paybacks are too slow. The gov. grants do not make up for the higher cost and potential lack of reliability for the average homeowner that isn't a plumber and HVAC tech. For your application, you really need a backup system for when things go wrong and I'm not suggesting Geo plus something else. Choose what gives you the most BTUs for the money in your area even if you improve the insulation/infiltration. Here are comments I wrote as a reply to someone elses Geothermal question. http://docs.google.com/Doc?docid=0Ad...a3ZiamY3&hl=en

This may look like a long winded answer but the time you take gathering info will pay you back x100. The lack of reliable information on the web about geothermal puts everyone at a disadvantage.

jogr 05-04-2010 09:51 PM

A geo unit isn't all that large to normally be a concern unless your utility room is small. No need to cut down trees - vertical wells or horizontal boring machines eliminate that concern.

But the geo cost and return on investment is a real issue that needs to be looked at carefully.

grifzila 05-05-2010 11:07 AM

Suprise - Size
 
Jogr brings up an important point that needs to be better understood by anyone considering an upgrade to their system. Available space for the upgrade needs to be on the long list of "preflight " considerations. Keep in mind that the average home space allocated to the heating system would be the size of a medium size closet. Any system can be jammed into the space available but the end cost of the servicability can be significant even if the reliability and efficentcy isn't compromised by some short cuts taken to get the hardware to fit a cramped location.

The geothermal main box needs other components that are not usually pictured in the sales literature. The newest models have nearly doubled in size to incorparate sound proofing, larger coils, and ECM blowers. The geo system may need some additional things - like: Water supply and return plumbing for heat exchanging, electric valves, filters for well water supplies to keep junk from fouling the valves and coils, water lines to and from the hot water heater if heat recovery is used to suppliment domestic hot water, check valves and surge tanks to control "water hammer" where valves control fast moving water, extra valves and plumbing to reroute stuff for testing, flushing, or temporary fix of a failure, and most important of all - ACCESS to everything to service and do routine maint. like filters and screen cleaning,pressure checks, temperature checks.

I remember seeing a check list for choosing and installing a HVAC contractor. I will find and post it here because it listed some interesting things that are too easy to overlook.

EdLank 05-05-2010 09:42 PM

I am not sure why there are comments about a geothermal not being able to sufficiently cool a house. If an air conditioner or heat pump can pump heat from a 72 house to 95 outside air as the heat sink, it sure would be less work to pump it instead to water/antifreeze chilled to 60. In winter in Pennsylvania (but not maybe Manitoba), the winters are often 20 or colder, so sourcing heat from 55 ground-warmed water rather than 20 air sounds a lot easier, too. We drop the thermostats settings as the outside gets colder, and can usually run all winter without "emergency" heat, even when 20. Not having to do that with geothermal is attractive. Also not having the outside air handler unit is attractive...it must be uncovered twice during the 24" snowstorms.

My understanding is that a huge portion of the cost of closed loop geothermal is burying the line. I have rocks and trees, too, and if I proceed, would expect to drill down, not run horizontal trenches. I have a two zone heat pump system, though. Double trouble.

SteveCo 10-20-2010 06:58 PM

Quote:

Originally Posted by EdLank (Post 438130)
I am not sure why there are comments about a geothermal not being able to sufficiently cool a house. If an air conditioner or heat pump can pump heat from a 72 house to 95 outside air as the heat sink, it sure would be less work to pump it instead to water/antifreeze chilled to 60. In winter in Pennsylvania (but not maybe Manitoba), the winters are often 20 or colder, so sourcing heat from 55 ground-warmed water rather than 20 air sounds a lot easier, too. We drop the thermostats settings as the outside gets colder, and can usually run all winter without "emergency" heat, even when 20. Not having to do that with geothermal is attractive. Also not having the outside air handler unit is attractive...it must be uncovered twice during the 24" snowstorms.

My understanding is that a huge portion of the cost of closed loop geothermal is burying the line. I have rocks and trees, too, and if I proceed, would expect to drill down, not run horizontal trenches. I have a two zone heat pump system, though. Double trouble.

Hey Ed. Did you go with a geothermal system? I'm struggling with the decision now with the rebates and all, seems like a good move but our furnace only burns 700 gal/yr. At today's prices this is tolerable, but in the event (when) prices rise, I may be sorry. What are you upgrading from? I guess you may not know how much it cost to heat your house without a full year's geothermal cycle. Any feedback would be helpfull. I'm located in Pottstown, PA so our weather is similar.
Thanks...Steve

michael77 11-14-2010 11:48 AM

you could go with a forced air heat pump with a gas fired furnace in a "dual fuel" setup. Gas furnace can be set up to run on propane if natural gas not available. This setup would be cheaper than a heat pump with electric strip backup heat. With this arrangement, the heat pump is cheaper to run until temperature is below say -5 to 0 deg C.

beenthere 11-14-2010 11:59 AM

LP has to be real cheap per gallon for it to cost less to use then a heat pump with electric aux heat.


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