I had a 4 ton Earthlinked horizontal pit installed here in Michigan last October. To date my electric usage has been about 125% per month more than the numbers calculated by the installer from his J calcs. The installers number were similar to another contractors numbers that also bid the project. Both certified Earthlinked installers.

I was told by the installer that the system will increase in performance over the next year or two as compared to the numbers that I'm seeing now. This is contributed to ground settling of the pit, and having an entire summer to heat the earth. I was also told the same info from Earthlinked. Earhtlinked informed me that the heat output of the system slowly decreases as you go through the winter months. Example: the temperature output measured at the plenum in late October will be higher as compared to late January.

Is this true, will this system gain in performance next year and the following? Has anyone else been told this? If so, how come the initial energy usage was not coneyed by the contractor.

I haven't heard that efficiency will increase.

It is true that if the pit has not been completely settled, it will gain a little (most likely unmeasurable) bit in capacity and efficiency. However, the soak should have done the job there.

One issue we've found on a few EarthLinked units is that there was a group with defective capacitors. The compressors would still run, but not smoothly. The amp. readings were high, too. Of course, this translated into higher bills, too. The first one we noticed had a backup electric meter, and that spurred us to check further.

It can be so that the earth will retain some residual heat/energy from having spent all summer cooling, but this is unlikely to cause a huge efficiency boost for an extended period of time. It is true that the output is decreased as the winter goes on, but this is true with any closed loop system.

At the very least, I'd have them check the capacitors and the current draw of the compressor. Make sure it falls in line. Post their findings for us here.

I would expect that your electric is higher than anticipated because of the abnormally cold weather. Operating cost comparisons are based on a 20 year weather average which means you may also look forward to some occasions where the bill is less than anticipated.
Other influincing factors include (but are not limited to) proper duct work, clean filters, and honest usage evaluation, such as are we including cost of hot water production and inadvertantly comparing to heat only projections. When you say usage, are you referring to actual kW or the bill?
Nature of the soil would matter as well. In spite of soaker hose use, clay could take some time to compact, while very wet soil may not hold crusher dust but would transfer heat fairly well. one of our sites was caught with the ground open during one of those early storms, and that may be influencing coil temps as well.
Keep us posted,
Joe

Joe, this  4 ton system only provides heat for the home, no water heating. I know that this past January here in Michigan was extremely cold, but here are my numbers for Kw usage. I have a separate meter for my geo, so it is easy to read and dedicated only for that.

My January usage was at 3025 Kw's. My installers numbers were at an estimated Kw usage for January of 1332 Kw's. Does this seem normal to use 227% more than predicted?

Is there nothing else on that meter? DTE allows you to take discount rate for all things heating and 1 water heater.
J

Nothing else on the meter but my GEO. I am still operating a tankless propane whole house water heater at this time.

I say he didn't correctly pack the earth down when he covered the loops with earth. Instead of covering the lines all at once, I've read it better to back fill a little, pack it down and back fill some more. Or even better yet, soak the ground with water as your packing the earth down. Perhaps you could soak the ground with water when it gets warmer, or run over it with some heavy equipment like a bulldozer or tank, but I say any natural settling is going to be minimal at this point. 
 

Compaction could certainly be a factor, but I hope crusher dust and soaker hose were used. Doing the math on your usage, you are paying about $50/wk right now to heat your home.......not bad for single digit and subzero weather. I don't know which savings calculator they used and how it dissects the usage and weather averages but your actual usage sounds reasonable for the weather we've had here. It might seem dissappointing, but compare the cost of 300-400 gals of propane and it's not too bad. You also know what your worst case scenario is; virtually every bill should be lower than this one.
Meanwhile, I presume you made sure bill was actual not estimated....So I would then look at previous questions about duct work and make a line by line comparison on the operating cost calc's. Disparities are generally easy to sort out.
J

Truckdriller

From NC Colder winter than usual but thank God I am not in MN.

Thermostat down set to 65 at night and a little higher during the day 66-68; up at 65 all the time

I have a new earthlinked system installed 4 tons down including .5 ton to condition basement and crawl and 3 tons up. Foamed the roof deck and crawl (also had vapor barrier). Will do in the future interior storms--already have exterior storms loads off beautaiful old windows. Previous owner had insulation blown into the walls

My electric bill came in higher than I had hoped considering all the insulation work we did--almost $7000. Our bill runs about $70 when not using HVAC. Factoring out the normal bill, I heated a 3700 sq ft histioric home. It has a huge foyer that open to the 2nd floor for about $250. I guess its not that bad but your hear folks with such low bills.

Just curious How do we know if we have that faulty equipment.
Did not stay outside the whole time the guys backfilled. Some sand was put in each put. There was always a regular hose on site. don't quote me, but I think they used mosttly the same material to backfill. How do I know if there is a compaction problem

We discussed the operation of the system with the installer and we were assusred that all is normal. It was cycling correctly.

Considering the issues with the home, I have been concerned about undersizing.

Sounds cheap. This thread was started by someone with only 4 tons spending $50/wk.
J

J
Thanks. We feel like a new parent with an infant in the house and the Dr. Spock has been thrown out by mistake with the dirty diapers.

I just installed a DX system for about $47K. This link is the first I have heard about loosing efficiency during the winter months. Is it a proven fact for the geo systems and how much will you loose? Should I bring back my old wood burner for the Dec-Feb cold season here in NC?

Electric bills don't seem to be outlandish, but don't have anything to compare to as we have not lived fulltime in the house during the winter. What should I be looking for?

My EWT at installation last June was 52*. We've had an unusually cold winter and my EWT is currently around 38*. Sometime in mid March I would expect to see the EWT starting to increase returning to the normal ground temp in mid summer.

I thought that efficiency ratings were measured using very low EWT's so that the published COP numbers were more of a worse case scenario. But I also have read on these boards that there is no "standards" for calculating COP so the methods that Water Furnace uses may not be the same as Climate Master, Hydro Delta.........making true COP comparisons difficult.

I presume efficiency has to drop a little as EWT's drop in the winter. Doesn't it stand to reason that it's harder to make warm air from colder water?


It was really cold in my area (single digits for about 10 days) in January which is unusual. My electric bill this year is going to be equal to my electric + propane last year. However, on the whole I think I'm about $1,500 ahead based on my 8 months of use.

Cold weather has been overly blamed for some geo systems not performing up to the owners' expectations. In Michigan, in the Lansing area, according to the National Weather Service data, January 2009 had 1524 heating degree days, compared to 1341 for a normal year. If we accept the notion that HDD is a good indicator of heating needs of a given home, Jan was about 14% colder than normal.

It would be nice if mllewellyn's geo installer will provide a new performance data sheet, using the actual weather data for comparison to the unit's performance for last month.

I live in Michigan not far from Lansing, my Tranquility 27 3 ton ran almost constantly in January without using aux heat, my average daily heating and hot water electric use was 32 KWH. This replaced an estimated daily use of 5.8 gallons of propane. Comparing costs, it is $110 electric @ $.11 per KWH (includes 10% increase for Jan) vs $439 propane @ 2.44 per gallon (what I paid in Nov 2008). The geo performance fits my expectation.

Regards, Masoud

The big difference Masoud, is the last 14% of heating requirement is handled by 100% aux. if your system is designed with say 95% geo in mind. therefore usage would be geometrically impacted and cause much more than a 14% increase in the electric bill.
I do not want to suggest that folks shouldn't ask questions here or of their contractor. But bear in mind that most cost calculators are based on a 20 year weather average and extra use this year means less in another.
J

DAP,
Simply put the colder the ground, the less -any- heat pump puts out. If you have a good outfit woriking for you, this would have been factored in.
J

I know this is a loaded question but is Masoud's 32 KWH usage fairly typical for a 3 ton unit?

I don't have a separate meter for my 4 ton Tranquilty 27 so I did a little interpretation of my electric bills from Dec 2008 and Dec 2007.

Heating degree days- 936 (2007) 932 (2008) so climate was approximately the same in December of the two years.

Electric useage based on 30 day cycle
Dec 2008- 3571 KWH
Dec 2007- 1751 KWH

Assuming things are equal I used 1820 more KWH in 2008 than I did in 2007. This equates to 60 KWH per day for heating. If you figure that there is electric in the 2007 bill to operate the blower on my old propane furnace the useage would actually be more than 60KWH.

I'm not upset with my performance because as my earlier post indicates I think I'm about$1,500 ahead of where I would have been if I kept the old propance furnace. I'm just wondering what "average" KWH consumption might be.

Too many unknowns to compare such as sf, insulation, set point, number of occupants, ductwork, design load.......Off the cuff Masoud's usage seems remarkably low (expecially with hot water added in). He does point out that his aux coil is turned off so around here with 3 tons that indicates a very well insulated home, some good conservation habits, and a low set point.....or a small house with an oversized heatpump. Either way as you pointed out geo wins.
J

Kip

My KWH/day are about 42. I think Masoud is a bit farther south and has fewer HDD. Below is my post from another thread to fill in the rest:

My measurements are just approximations, but you might find them interesting. Just read my meter for the month of January and used about 1,300 KWH because of my Geo furnace. (this is my first winter with it). I subtracted the KWH from other uses in the house by looking at my average usage for the last 2 years. The nearest weather station 50 miles south of me in Green Bay, WI shows 1773 HDD for January. For my 1900 sq ft old farm house that would be .73 KWH/HDD. We were down to -22° for a couple days and didn't get above 32° for the entire month. I don't set back my thermostat at all and my auxillary electric heat strip is turned off by means of the dip switch in the waterfurnace.

ps.
oh, I have a 4 ton Waterfurnace