I'll try to keep it brief. I have a new construction 6266 sqft (includes conditioned basement), 54508 cuft home. Heating costs seem high. Over $700 Nov-Dec and over $500 Dec-Jan after making some adjustments. All energy efficient appliances, all LED lights. My aux heating strip comes on too frequently (my opinion). Installer says that is normal with our cold temperatures. He claims under 32 degrees it should come on. Before I call the installer and insist they fully test the system I wanted to get some opinions. Am I undersized too much for the zone I'm in? If so is it reasonable to ask them to install a larger one with me paying only difference in cost of larger unit (they cover labor since its their mistake?) Here's all the info I can gather. 1) I live in a suburb of Cleveland, OH. 2) Don't know heat loss calcs but home is rated HERS 44, 2189 CFM50 blower test (2.4 ACH). 3) Brand new Climatemaster Tranquility 30 TT064 (I think its 4 ton heating on St2) 4) I think it's a vertical closed loop field 150 feet x 3? Not positive on this one and can't get a definitive answer from them. 5) ~$0.12/kWh cost. 4716 kWh this month, 6422 kWh last month. Sorry no baseline moved in during heating season. 6) My DATS says 98 degrees when I most recently checked. We like it warm at 71 degrees downstairs and 72 upstairs. I don't know EAT and LAT (sorry don't know how to measure) 7) Sorry don't know EWT or LWT (don't know how to measure and I would rather call installers out to check this since it should be under warranty) 8) I tried to find out balance point of system design but I think the HVAC rep I spoke to either didn't understand me or doesn't know. 9) Installer rep came out and basically said the aux heat should come on if the temp is under 32 degrees. That seems excessive for Cleveland since that would be almost all of winter. I might as well have bought an electric heater if that's the case. 10) My blower test projected annual heating cost of $817 which obviously is way off! Thank you all for your expertise. What I'm worried about is if the unit is too small for my home. If it is, then there's no point in testing the unit to make sure it functions. I need to have a discussion with the builder/installer to address the undersize. Otherwise, I'll call and insist they come out to check it.

2) Don't know heat loss calcs

How did they size the units without heat loss calcs?

Just to confirm that your entire electrical bill is $700 and $500, each for two winter months? You said those were heating costs, but that is everything, right? No other energy in the home?

Yes sorry that is total electric bill, not just heating cost. I'm not sure how they sized the units. Since I worked through the builder, I was not involved directly with the HVAC contractor. My builder seems to have done a good job with everything else so I trusted they picked an HVAC contractor who knew what they were doing. I can try to call my HVAC guy to see if they have the heat loss calc on file since it sounds like that should have been performed. Thanks.

Go to degreedays.net, and download spreadsheets of the daily base-65F heating degree-days, and add up the HDD for the EXACT dates between meter-readings.

Then report back the monthly HDD along with the kwh use during that period.

The 99% outside design temp( http://www.energystar.gov/ia/partners/bldrs_lenders_raters/downloads/Outdoor_Design_Conditions_508.pdf) for Cleveland is +6F, the mean January temperature is about +25F. Both December and January have been below the historical averages this season, which would mean even MORE use of strip heating than in an average year. But if they designed the system to require auxilliary heat whenever it's below 32F in a location with a winter mean-temp 5-8 F below that the system significantly undersized. (Best practices would size it at the very least to be able to handle the load at the historical 10 coldest weeks binned hourly mean temperature which in your case is about +27F. See: http://weatherspark.com/#!dashboard;a=USA/OH/Cleveland )

If it's an actual undersizing issue and not a functional problem the best paths forward will vary with the particulars. Having the room-by-room heat load in hand would be helpful, if you can dig it up.

3 vertical wells at 150', sounds like a rule of thumb design for 3 tons. TT 064 is a 5-ton I believe. So you are short looped if only 3 wells at 150'.

How is hot water made? Do you have a Desuperheater? Storage tank and Finish tank?

Chris

I could be wrong about the 3 loops. When I asked the HVAC guy who came out to give me a "tour" of my system, that is what he said but I don't think he was the one installing it. I will try to find out for sure. We have a desuperheater going to an 80gallon electric water heater. Will figure out my HDD also once I get home this evening.

If you have a desuperheater connected to just 1 tank that is a less efficient set up. Really should have an un-powered storage tank for the desuperheater to circulate water raising the temp over long run times of the heatpump.

Then when there is a draw of hot water, warm water from the storage tank enters the finish tank and doesn't require very much electricity to get up to final temp.

Chris

Yes sorry that is total electric bill, not just heating cost.

Just curious as to what history you have that makes you think the heating bills are out of order. Your home is substantially more than twice as large as average in the depths of a cold winter. I think the average home (whatever that is) spends a thousand to heat each Winter. With respect to that, you don't seem too far out of whack.

He claims under 32 degrees it should come on.

Is he talking about outdoor temperature or your loop temperature?

Dana1, I added up the HDD for 11/16-12/17. Total is 1070 and my total electric usage was 6422 kWh during that time. For 12/18-1/17 total is 1137 and total usage 4716kWh. I don't know if the 32 degree number that was given to me was just his way of saying...If it's below freezing, aux heat will come on. I called the HVAC installers today and left a message. Still waiting for a reply and maybe some answers.

ChrisJ, I'm pretty sure I don't have any storage tanks. I know the geothermal is connected to the water heater and I am assuming that means I have a desuperheater?

ICF hybrid, you are correct. I have no history for this home since it is new construction. Please keep in mind the total square footage includes my basement which is ICF. My living finished space is about 4100 sqft. I included all the square footage because my energy rater included it and the basement is conditioned. I can only estimate based on my colleagues and friends. I know of 2 similar sized homes with natural gas having recent utility (electric plus gas) bills of about $350 and $400. Another home with geothermal but is over 16,000 sqft cost $1000 per month (but this is a much older home). First energy also gave an estimated utility cost based on the size of my home and type of heating and their estimate was just under $400 average. Am I expecting too much out of geothermal? I respect everyone's opinion here and if the verdict is nothing is wrong, then so be it. However, if something does not sound right, I will push my HVAC installer to do something about it. I just don't want to be unreasonable and that's why I'm asking for everyone's opinion here. Thanks.

Am I expecting too much out of geothermal?

No..

My Dec stats:
2100 sqft house - (1945ish build house with updates)
HDD 1024.9 - Electric use for geo only -> 891 kwh (including any aux heat)


Seems like many installers (who really know what they are doing) would never install just one hot water heater. They would install a buffer tank wish would dump into a water heater. They have been many cases due to 'accidental' siphoning where the hot water heater ends up dumping heat back into the loop... not a good thing for your electric bill.

TT064 is a 5 ton unit.

"He claims under 32 degrees it should come on." - If that is really true, I would say your system is severely undersized.

Hopefully there are just some things you don't quite understand yet... I would talk to your installer and post back some updates.

Air to Air heat pumps can work under 32* without aux heat, your ground source heat pump should easily keep house warm without aux.

Are you using a programable thermostat with set backs? You mention liking it 71-72*. Bringing the house temp back up can bring on a lot of aux heat.

Chris

First you need to establish a baseline electric use before you say bills are high, know what is being used for heating. I had a customer recently who said the same thing and showed me his January bill of $650ish. He happened to have a seperate meter for the geo so we were able to establish that the household consumption was about the same as the heating consumption. I asked him if he burned a lot of Christmas lights and he beamed with pride.

His house hold base use turned out to be about $200/mo due to a lot of contributors. Suddenly the geo didn't look so bad when we established that it was only using $150-$325/mo.

So if you have a $150/mo base use that would make your heating bill about $350 and up to $50 of that might be hot water depending on how things are billed. That'd be pretty good. You can't even know something is wrong until you make this seperation.

Yes DSH without a buffer tank is a poor performing combination. However the manufacturers still offer it as a valid configuration so an installer that spends his time in factory training vs here may not know any better.

ChrisJ. I have a Control4 thermostat. It's part of my home automation system and I've double checked to make sure that it wasn't causing my issues. I have no setback. Upstairs is set to 72. Downstairs set to 71 because we like to sleep in a warm room. Emergency heat doesn't come on until 4 degrees from setpoint. I don't think it's my thermostat. I also don't think that "32 degree" is my true balance point because I notice the emergency heat doesn't kick in until maybe 20 degree temps hit.

Joe.ami (and ICF hybrid) I will try to separate the geo from everything else. There's no way I can get a reading from only my geo, but I can isolate everything else except for my hot water heater, fridge and alarm system. Christmas lights might partially explain my very latest bill, but not the first one. Plus I don't go crazy with lights and they are all LED.

Do you all suggest I add a storage tank? Does it make that large of a difference?

I have not visited control 4 lately, but they were not a satisfactory control last I looked a couple years ago. Aux on at 20 may be right in your area. Yes a buffer or no DSH. I have seen unbuffered finish tanks lose heat to the geo (raise cost of hot water.

Just got off the phone with my installer. I'm not feeling very confident about their knowledge of these systems. I asked if they did a heat load test and calculations to size my system. He said they did but he doesn't know off the top of his head and he has to dig it up. When I actually asked him to dig it up for me, he told me "you want me to waste my time? The system is sized correctly". When I asked him for the balance point they used, he told me 72 degrees??? I also asked about the DSH. He told me to go talk to my plumber! He has no idea about the storage tank. I think its time I contacted my builder. I usually do a lot of homework before purchasing anything but when we purchased this home, I let my guard down because the builder seemed to be competent and seemed to have lots of experience as a "green builder". My home has ICF, SIS sheathing, lowE windows/doors, caulk and sealed, and blown cellulose so I assumed my geo contractor would be good. My mistake I guess. Maybe I'll be lucky and Joe.ami and ICFhybrid are correct and nothing is wrong. I guess we are having a historically cold winter.

Thanks to everyone who chimed in for your suggestions. At this point I'm going to do some investigating for my base utility usage and the DSH setup and I'll post an update later on when I have everything sorted out.

Posted By ChrisJ on 23 Jan 2014 07:15 AM
Air to Air heat pumps can work under 32* without aux heat, your ground source heat pump should easily keep house warm without aux.

Are you using a programable thermostat with set backs? You mention liking it 71-72*. Bringing the house temp back up can bring on a lot of aux heat.

Chris

That's only true if the GSHP isn't undersized for the total load, and functioning properly, which are among several things he is trying to figure out.

With kwh/HDD data it might be possible to determine an order of magnitude of just how much the auxilliary heat is contributing to the total power use, but it'll take at least a few billing months, over a range of monthly HDD.

At 12 cents/kwh even a 20F outdoor setpoint for enabling the auxilliary heating might be on the high side for a location where the 99th percentile temperature bin is +6F.  If the GSHP is functioning to spec but undersized for the load, the cheapest way out might be to heat one significant sized zone with a mini-split to allow the GSHP sufficient margin on the rest of the house to not need the aux heat to trip on until it's below +10F. In a Cleveland climate a better class mini-split will use less than 1/3 the amount of power of auxilliary strip heaters. It's not ideal, but far less expensive than scrapping the current GSHP for a bigger unit and adding more ground heat exchange capacity.  For a house than scored a HERS rating of 44 this may be a viable option, but the particulars matter. (Room by room heat load calculations and the zoning plan are critical.)

Would anyone recommend for the time being to turn off my DSH until I get a storage tank installed? Is this relatively easy to do? I've contacted my plumber for a quote on a storage tank. Any recs on size and model?

Dana1, looked into the mini-split but I don't like the aesthetic value of the mini-split system.

I think along with your HVAC contractor getting you a heat loss for the home, you need to find out more about your loop. I would have them give you the Entering Water Temperature (EWT) and Leaving Water Temperature(LWT) to see how your loop is performing. It could be that your loop is close to hitting freeze protection so your unit is not producing the amount of heat it is supposed to and thats why aux heat is coming on. Typically 1 bore hole per 1 ton of system, since you have a 5 ton system you should have 5 bore holes at about 200' each(depending on ground conditions and pipe size). For a high efficiency home(without knowing heat loss) it is possible that a 5 ton system can heat 6,000 sq feet, but that home better be VERY tight and well insulated(sorry I don't know what a HERS rating is) but it sounds like that is your home.

I will echo the others that you should have a 50 gallon preheat tank for your geo system, click on my Youtube link below to see some videos of systems or my WEL server to see a diagram of a desuperheater storage tank.

He told me to go talk to my plumber! He has no idea about the storage tank.

Not a good sign... Maybe the plumber could re-plumb the guys house without any blue-prints. Do you think he would guess correctly where to install the sink? Anyway... check out this post.

http://www.greenbuildingtalk.com/Forums/tabid/53/aff/13/aft/82037/afv/topic/afpgj/1/Default.aspx#118970

There is a nice diagram posted by Bergy.

The DSH is turned on/off via one of the DIP switches. Pretty easy to do if you know the correct one to flip. But it's still unclear if the DSH has anything to do with your problem. We really need more data.. ie loop temps, and any particle electric breakdown would help.

Yes, before we get too carried away, let's try to establish a baseline electric use for the home, and note Christmas lights in use. I'm betting the "adjustment" was removal of the JW3 jumper.
Dec. to Jan bill of $500 for all heat, hot water, Christmas lights and other household consumption for a 6,000 SF house.......? and it's colder than usual......? Is this really panic mode?

With the Climate master you can turn off the breaker to auxiliary. If your house immediately has trouble keeping up then you are probably dependant on auxiliary, but I think you'll find you are not.