New to Geo and Confused at high energy bills and lack of comfort

Discussion in 'Maintenance and Troubleshooting' started by Mudly007, Jan 24, 2011.

  1. Mudly007

    Mudly007 New Member

    I am a do it yourself kind of person and do a lot of research when I make a decision. I recently built my own home and decided to use Energy Efficiency as the decision making key to all of my building decisions. My home is a Ranch with a 2300 sqft. main and 2300 sqft. basement. Every single lighting fixture has an LED bulb or is an LED can light (spent a fortune on lights). I have a tankless water heater for backup, and my dryer, and cook top are gas. My oven is electric but I use it approximately one time/week.

    The windows are manufactured by Solaris and are rated very high. All windows are casement of fixed picture. Most windows are fixed picture to eliminate the extra seals and potential leak possibility of opening windows. All doors are the best insulated I could find locally. All windows and doors have been sealed with foam and window Tape.

    The ceiling is insulated R50 blown in fiberglass except for the great room ceiling which as 6" of foam sprayed to the roof deck, the walls are insulated with 3-3.5 inches of polyurethane foam (say R21ish). The Basement Walls are Superior Walls (They come R5) with 3-4 inches of polyurethane foam added (Total R26ish). The basement floor is insulated with 2" of spray foam under the slab. The front of my home has also has the added insulation of B&B siding with foam for rigidity.

    I have a 4 ton Waterfurnace Envision Forced Air System installed in the home. It uses a 1/2HP ECM blower motor and I believe it has a 8KW heating element for AUX. It has the desuperheater option and it is currently working. There is a 6' deep trench that is 600' long. I believe there are 3 loops in the trench.

    My Geo Installer gave me a sheet that says it should cost me aprox $1100 to head and cool for a year. SOUNDS AMAZING.

    My Electric usage so far for the 2 months in my new home have been 3567KWh ($440.98) in December and 4141Hwh ($546.19) in January. Besides the cost of running the system being way more than $1100/year my home is not staying warm enough. I have it set to 69 and it feels cold. I have other thermostats ranging from 65-67 but the waterfurnace branded stat says 69 consistently. My system runs 24/7 in Y1 and most of the time in Y2. The AUX seems to be running a lot at night and is almost always on in the AM. I realize this is normal and that you would not size a system for the extremist of temps. I know AUX is supposed to come on in those cases.

    It has been cold the past 2 nights and the system has been running full out Y2 with Aux and my house is not maintaining set point on the thermostat. This AM it was 64 (62 on other stats). It feels cold. I have space heaters in the house to keep my newborn warm enough.

    I was under the impression GEO was a more even, more consistent, and more efficient heat. I have never paid this much to heat my home…even when I was using propane. I have also never been uncomfortable and unable to heat my house.

    I can burn wood in my fireplace and get my main room to low 70 without trouble. The only problem is the rest of my house gets cold. Once the fire goes out the temp in the home equalizes and the system runs harder for the next day just to get things back up.

    Sorry long winded but I wanted to get some background. What should I be checking? I feel very little air from registers and the air definitely doesn’t feel warm like my propane heat used to. Even when unit is heating in AUX the duct work from the system doesn’t feel extremely warm. Is warmer but not what I would expect.

    I am afraid I am undersized and not making enough BTU… The installer came over and covered all of my return air duct work in the basement to improve air flow. He states that the air temp is in the mid 90’s in Y2 so there is nothing wrong with the loop or the geo unit. He is telling me that I have the option to install a 1HP motor and that will help.

    How do I know if this is the truth? How do I know if he wants to avoid changing out the system?
  2. urthbuoy

    urthbuoy Well-Known Member Industry Professional Forum Leader

    Some thoughts

    Firstly, sorry to hear that you're having issues with your system.

    A couple of general thoughts enter my mind.

    - you should (or your installer) have at least the initial startup parameters for your system. It is difficult for us to diagnose from afar without some measurements presented to us. See this sticky We would need to see a heat loss heat gain to get started on your system sizing.

    - increasing air flow with a larger blower will not increase heating capacity. It will just increase airflow. Useful if there is not air getting to certain portions of your house.

    - looking up spec's. An Envision unit (depends on model) uses between 2-3kwh, so if it ran full time for an entire 30-day month - it would use up 3x24x30=2160kwh. Two months = 4320kwh. That is just to give you an idea as to what the max. draw would be from your heat pump. It is very unlikely to be running full time.

    - I'm a little worried about the one-trench, 3-loops layout? What is the separation between loops? Your entering water temperature (EWT) is important here as well.
  3. urthbuoy

    urthbuoy Well-Known Member Industry Professional Forum Leader

    One more thought

    In general, internal building loads are estimated as part of our heat loss heat gains. If you went ultra-efficient, then those loads will need to be made up by the HVAC system. Another thing to look for in your heat loss heat gain.
  4. engineer

    engineer Well-Known Member Industry Professional Forum Leader

    Those consumption figures suggest unit is operating solely or nearly so on aux strips

    Trick will be to find out why.
  5. AMI Contracting

    AMI Contracting A nice Van Morrison song Industry Professional Forum Leader

    For all the information in your first post there is very little that helps us. There is a trouble shooters check list that tells us what we need.
    You did not specify wether the electric bills were for just heating or the wholde house.
    At loosley 12 cents a kwh if you were in my area last month a $400 electric bill might be about right ($100 for misc. usage and $300 for heat and DHW) as we were below freezing for a month straight.
    Thermostats only know the temp where they are at. If there is a lot of disparity in temps from room to room, it is a duct problem not a heat pump problem.
    With out much info, I'm more suspicious of the installer's knowledge and duct design.
    Do not purchase the larger blower.
    Good Luck,
  6. Mudly007

    Mudly007 New Member

    I was asked to provide the following:

    1) Where you live
    2) Heat loss/gain calculations for your home
    3) Brand, size (model) and type of heat pump
    4) Type of loop field (open/closed/vertical/horizontal) size and design parameters
    5) Average cost/Kwh of electricity and consumption
    6) Entering and leaving air temperatures (EAT, LAT) measured immediately upstream and downstream of the heat pump
    7) Entering and leaving water temperatures (EWT, LWT) measured at the heat pump(s)
    8) Percent of load to be covered by geo and balance point
    9) Installers assessment of your systems operation.
    10) Projected operating costs, actual operating cost and previous heating and cooling costs

    1) I live in Cedar Springs, MI 49319
    2) I have a UA calculation of 659 based on a REScheck program used in my state to determine if a home meets insulating specifications (I am 12% better than Code). That calculation comes from entering everything that makes up my building envelope. How that relates to heat loss is where I get lost. Not sure how to determine the heat loss of my home.
    3) Unit is a Waterfurnace Envision ND049 with Dual stage compressor and ECM2 Fan Motor. Unit is equipped with desuperheater and EAL(H)10 electric heat coil
    4) My loop is a closed loop horizontal system in wet/clay soils. According to my contractor the trench is 600’ long, 6’ deep and has 6 pipes.
    5) Average cost is around $0.12
    6) As of today the EAT was 68F, and the LAT was 86F in Stage 2 no AUX
    7) As of today the EWT was 30.4F and the LWT was 27.2F in Stage 2 no AUX
    8) Don’t know the balance point or how to determine it.
    9) Installer has increased my fan size from 1/2HP to 1HP claiming I don't have the proper air flow
    10) Projected annual cost is $1124 based on my installers calculations. I have requested another cop of the GEOLINK report from him to get breakdown.

    This stuff can be confusing. Very interested in understanding better.
  7. Mark Custis

    Mark Custis Not soon. Industry Professional Forum Leader

    Number 9

    Who did the duct work? Did the geo guy see it before the instalation?
  8. AMI Contracting

    AMI Contracting A nice Van Morrison song Industry Professional Forum Leader

    That offers some of the design info. The Geo link report may have load and balance point on it.
    We know that we had uncommon ferocity of weather in December for MI.
    Is your geo on it's own electric meter or does it share with the house?
    Is your water heater electric or gas; new with heat pump or existing?
  9. Mudly007

    Mudly007 New Member

    Mark, The home is a new construction. The Geo Guy did all of the duct work and the installation of the waterfurnace. The loop was installed by his contractor that is the premier loop guy in the area. He did the loop based on the tonnage needed for the system

    AMI, First, I appreciate you taking interest in this situation. New to forum communication. You are right, it was cold. To be honest I am happy it has been so cold so that the system will get run through its paces early on. I am trying to be realistic regarding this system and know that the AUX is included to handle these colder than normal situations. My fear is that the geo is undersized requiring much more AUX to keep things at setpoint on a regular basis. The contractor did install the new motor and the airflow to the house has increased significantly. Only problem (I think it is a problem) is the LAT is now 81 in Y1 and 86 in Y2. Before fan change it was in the mid 90s. My contractor is now stating that the WF thermostat is a problem and wants to switch to a White Rogers because the WF isn't going Y2 fast enough. Is there a better thermostat than another?

    I got a better thermometer than the one the tech was using (his had wires hanging out of it) I used a calibrated Fluke probe and got in Y2:

    LAT: 86.3F
    EAT: 68.5F
    LWT: 26.6F
    EWT: 31.9F

    I have attached the GEOLINK for my home to this post.

    Attached Files:

    Last edited: Jan 26, 2011
  10. zach

    zach Member Forum Leader

    One of the pros will verify but looking here (page 12 using the ground loop heat pump column as you are closed loop):

    At 32* EWT your 049 will make 37,400 BTUh in second stage (at least that is how I am interpreting the table).

    According to your geolink your heat load is 53,439 BTUh at 5* F. It looks like the designer used a setpoint of 68* for the calculation.

    I'd be curious to see what percentage of the time your design calls for AUX.
    Last edited: Jan 26, 2011
  11. Mudly007

    Mudly007 New Member

    according to the GeoLink it says the Auxilary Heat is 1% of the heating load using 138kWh and costing $17 anually...
  12. zach

    zach Member Forum Leader


    I am a mere homeowner. I am going to let the pros chime in here. I am nearly sure I am reading the Waterfurnace spec table correctly. Do you see it?

    If I am it would seem your machine will cover about 70% of your building load at design temp.

    My design covers up into the 90's percent wise with the numbers making sense against calculated building load and machine output.
  13. dgbair

    dgbair Just a hobby Forum Leader

    Are you heating both the basement and main floor?
  14. Mudly007

    Mudly007 New Member

    Yes, the system is heating my entire home. That includes the basement which is insulated to the hilt. Total conditioned space in this home is 4600sqft when you include the basement level.
  15. AMI Contracting

    AMI Contracting A nice Van Morrison song Industry Professional Forum Leader

    Common misperception is -covering 99% of the load means a system covers 99% of the max heat loss. In reality peak loss is only a small fraction of the heat season and heat pump still provides part of the requirement.
    So to arrive at 1%, calculations are saying it is seldom you require more than max geo contribution and even less often peak requirement. Even then there is significant geo contribution.
    One of the guys here often says (paraphrased) 80% of the load 90% of the time......
  16. zach

    zach Member Forum Leader


    Understand what you are saying. Am I reading the WF table correctly?

    I have a design graph which plots load lines against BIN hours and heat pump capacity. If Mudly has something like this I'd be curious to see what it looks like.
    Last edited: Jan 27, 2011
  17. Mudly007

    Mudly007 New Member

    I am installing a device that will isolate the geo and aux heat from the rest of the home electrical system as well as meter KWH usage. I am hoping this tells me more about how much Auxilary usage there currently is.

    There is so much hype about geothermal and how amazing it is. I have been told the comfort is unparalleled and the heat is so much more even, and the cost is so very much less. I was excited for all of those things and I jumped on the bus. I am really hoping my issues are more installation problems than an actual reality of how the system works.

    Can anyone chime in on what the geolink is saying. Is it telling me that at 5F my heating loss is 53,439 Btuh. However, in stage 2 the system is capable of producing producing aprox 40,000 Btuh. So basically when the temp is 5 or below the aux has to provide 13,439 Btuh to keep the house at 68F. To me that would mean above 5F and up to the temp where 40,000 Btu is enough to maintian the house the AUX coils would be active. Is this the case? Is there a way to calculate what that temp is?
  18. Mark Custis

    Mark Custis Not soon. Industry Professional Forum Leader

    I go on the road for a day with out G3

    Anyone here that does ice fishing

    Zack: You should try it next year, but you have the tables mastered. You learn well.

    Mudly007: Do not dispare things can be fixed. You should have seen the cow that hatched when I use pex instead of sdlr 11 on a certain pond in NY. Joe and I are blood brothers as we have been doing it before it was the "NEW IN THING", we know how it works and why it does not. (Sorry to all the other great heads that work here, Joe and I are close by.).

    I will side with Joe and reread the entire thread after supper. I do not think all is lost the loop may need to settle etc. Is strip heat via the electric supplier your cheapest AUX fuel?
  19. Verdae

    Verdae Member


    I will jump in here now, with a different take.

    The unit is sized to run on AUX electric heat for a significant part of the load. The fact that the loop temp is about 30F shows the loop is capable of delivering the draw of the unit, but the problem seems to be that the contractor did not revise his calculated output of the geo unit at the design loop temperature and this caused an under calculation of how much the AUX has to run at the 5F design temperature. Your unit seems to be working about as it should under these conditions, just not as you or your contractor thought it would.

    I am bothered by the failure of the electric strip heater to provide the needed supplemental heat. What is the kw size of the electric strip heater.

    You might also have a performance issue with the house and it might have a higher load than the manual J calculations predicted. With high performance homes, small things can undermine the performance. Is the ductwork in unconditioned spaces? Was the duct sealed with mastic? Was the ductwork leak tested? Do you have air leaks into the attic from can lights, attic door and such? Was the rim joist sealed to the Superior wall with foam? Are there unsealed holes for wires and such going to the outside or attic? Is the 2" space around the fireplace flue air sealed? Air leaks simply bypass insulation. The Energy Star program has a big check list to prevent the performance degradation "standard" building practices can cause. Failure to air seal the tub/shower area insulation is a big one.

    Did you have a blower door test done and is your home Energy Star rated? If so I would like to know what the rater calculated the design load to be. The Energy Star rating is a performance based rating and will give a much better calculated design load and predicted energy use than any manual J calculation.

    Did you take pressure readings of the inlet and outlet of the ground loop when taking temp readings? This will allow us to calculate flow rate and allow a better understanding of performance of the unit.

    To those who I have been having the sizing discussion with on another thread, this homeowners situation is the downside of sizing for 80% of design load.
  20. Mudly007

    Mudly007 New Member

    The electric strip heat problem was solved. In the beginning the contractor had the auxiliary circuit unhooked to ensure that a contractor working on the home couldn’t boost the inside home temp up higher than design and kick in the aux strips all the time. The first time the system didn’t keep up he came out and realized he had not hooked that back up. He enabled that part of the system. However, he forgot to program properly so instead of no AUX the unit started to run AUX only when it was needed, meaning the heat pump portion was turning off. He came out and fixed that problem and the temp in the house could be maintained. The next problem was that the AUX was on a lot. He did airflow readings and the airflow through the house was bad. You couldn’t feel air movement from most of the registers. He then upgraded the fan and took more readings. Apparently the Aux heat was kicking in and throwing off his readings so he unhooked it again to do tests. He forgot to hook it back up so again the house wasn’t keeping temp. The AUX problem was the contractors and that problem is solved.
    There is no ductwork in unconditioned spaces and all of the ductwork is sealed with mastic sealant but has never been leak tested. The attic access points are insulated well and all can lights are the better air tight housings. I have Cree LED can lights installed. I don’t believe this is a significant loss but I have no proof. All of the wire penetrations to the attic are sealed with fire foam per code. The rim joists are also sealed with sprayed in rigid foam. I have not done any performance tests on the home but I really tried to do everything I could to leak proof the home.
    The pressure readings on the loop were 71 psi and 74 psi.
    The temps in the house range from 70 to 68 on the main floor and are 66-67 in the basement. The even heat in the house has improved significantly with the addition of the 1HP blower motor. So far the temps have been in the low 20s and the home is running in Stage 1 and keeping up. I has actually turned off on a few occasions. This wasn’t happening before. We are supposed to have some 5 degree nights coming up so I will be interested in seeing what happens. The last thing my contractor did was clear and re-setup the thermostat with Waterfurnace on the phone. Seems like thermostat settings are extremely important. Is this the case? What exactly can you change with the thermostat?

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