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ICF Consumer: Looking for Peace of mind....
Last Post 17 Feb 2009 10:43 AM by mtfalen. 18 Replies.
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mtfalen
New Member
Posts:12
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| 19 Jan 2009 04:00 PM |
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New member here from the frigid cold of Ohio. Let me start by saying that I have enjoyed for months reading through many of your posts about ICF construction. After taking the plunge and investing in the product, I need your help....
My wife and I have just moved into our newly constructed home. 3200 sq. ft. two-story with first-floor master suite. Walkout basement, currently not finished. Entire house is ICF, attic is R-38 cellulose.
We spent considerable time researching the HVAC system as to not "buy a ferrari and put in a yugo engine," and decided to go with the Carrier Infinity packaged heat pump with variable air handler and 3 zones. Our main decision here was based on the calculated load requirements of the home being much less than the smallest gas furnace and humidity considerations, and decided to not to consider additional investment into the Hybrid heat option due to the Manual J figures, estimating annual costs to heat/cool the home with this equipment at $1400, which we found very reasonable. (No natural gas is available, so propane would be our gas option)
The temp is set at 68 degrees mostly, with a setback to 66 during the night and day when unoccupied in the main zone (first floor). The second floor is set at 65 (currently not occupied, my wife is expecting our first child in June) and the basement is very low at around 60.
Now to the point.....SOMETHING IS SERIOUSLY WRONG!!! The electric heat was fired up around 10/31 during construction for paint, flooring, etc. I was astounded to see my Kwh usage for the first 2 weeks until my meter was read to be around 2,000. So I thought ok, it's electric resistance heat, which is expensive. So I got on the builder to get the heat pump and zoning installed. The delay was the excavation getting the grade built up to the needed level to set the heat pump. Needless to say, it didn't happen very timely, 30 days went by, and my usage from 11/15-12/15 topped 5500 Kwh! Finally, on 12/30 my heat pump was installed and programmed, etc. So I prepared myself for the big recovery, but it never came.....
Usage from 12/30 - 1/15, another 2000 Kwh. Now I am tracking daily at the meter....246, 313, 185, 197 since the 15th. Now granted, the 16th and 17th were the coldest days so far this winter with average temps around 0 degrees F, but this usage seems crazy to me.
Now I can tell you, that the distributor for Carrier has been trying to get the Carrier product in front of this builder for some time and through my deal on the Carrier package, the builder was able to get a blower door test performed, the results of which I have yet to see, but have been told they were fantastic. The only recommendation that came was a sealing of all can lights on the second story (even though they are supposed to be manufactured that way :( ). In any event, there are only 8 of them, and that was done.
Wow, I've gone on forever, thanks to those still with me. Currently, the builder is talking with the contractor and the distributor, etc. Everyone is obviously busy with the season low temps and the family who has amazingly comfortable heat at a very expensive price takes a definite back seat to those with no heat at all.....waiting on a service call...but my bills since 10/31 have topped the $1400 annual estimate from the manual J calcs.
Any HVAC experts out there? This has to be a mistake right? My air handler or heat pump has to be defective or installed/wired incorrectly, right? I am ready to find and solve this problem, unlike others who spout that ICF is not worth the cost, just feeling a bit overwhelmed after all of the investment in the ICF and the Carrier system....I'm a modest guy with a modest lifestyle, this is truly my dream home and we plan to be there a very very long time......Based on all the research, ICF made great sense, Carrier Infinity made great sense, but the results are not matching the research!
The Carrier system is a 16 SEER, the SHPF is 9.5 or 10 (can't remember exactly), but very high efficiency. I can get the exact models if it makes a difference.
I should probably note that I have ruled out a faulty meter and something else causing the usage by turning the system off for a full 24 hour period and using only about 22 Kwh. with outside temps in the 20's, the house never got below 60 in that period which I thought was pretty amazing and further supported that my heat loss is very good. However, even at 60 degrees, my wife did not appreciate my experiment. :)
Thanks for listening and thanks in advance for any ideas....
Mike |
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LarryT
New Member
Posts:43
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| 19 Jan 2009 05:53 PM |
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My experience with heat pumps is aboput 4 years old, but at that time, they didn't operate in that mode under 25F. Below that temp, the strip heat is all they ran on. I assume yours is going to operate in a similar fashion. You're running about 35,000 BTU/hr over the 24 hr period. How does that compare to the calcs? |
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mtfalen
New Member
Posts:12
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| 19 Jan 2009 06:40 PM |
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The total building load is 49000 Btuh, by zone, the main living area is 23400, second floor 15000, basement 11400. Thanks for taking the time review! |
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ICFconstruction
Advanced Member
Posts:716
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| 19 Jan 2009 06:53 PM |
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You may wish to put this thread on the "geothermal heat pump" forum. Because your problem lies with that or your electric HVAC. You got a good initial report on your blower door test, so unless you have single pane window, the heat system is the problem. You could have thermal imaging done of your house.
I have heard mixed results from heat pumps, I don't think I will do it on my own next house. One builder I have built a couple houses for used blow-in only for the attic then had blower door, thermal imaging done. His next one will get urethane in the attic. |
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| Brad Kvanbek - ICFconstruction.net |
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LarryT
New Member
Posts:43
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| 19 Jan 2009 09:14 PM |
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Mike is this a geothermal pump or air/air (most common)? |
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mtfalen
New Member
Posts:12
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| 20 Jan 2009 12:51 AM |
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Larry, this is an air source heat pump. |
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FTMbuilder
New Member
Posts:2
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| 24 Jan 2009 10:15 AM |
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Sorry for your woes!
Don't worry you have made the right choice, you have invested in the right infrastructure, and over time you will be way ahead. Unfortunately, you are stuck on the cutting edge and many HVAC contractors and especially HVAC salespeople are not that sharp. The science has changed, and we have had a problem getting the right info for HVAC as well. We have tried many different heating designs and systems in the ICF houses we have built except a conventional air source heat pump. I am surprised in climate that it was recommended. At the very least a hybrid heat pump, which uses gas and electric.
In my opinion, heat pumps are only really effective for heating down to about 40 degrees, after that they are energy hogs, even if your house is ICF. You may find a balance in the fall and spring months when temps are more moderate, and heat pumps are really effective. One thing you may try is finding a temp you like and sticking with it. ICF houses like to stay at the same temp. A great deal of energy is lost in the cycling up and down. Also, did you install a whole house venting system ERV? HRV? And yes, its pretty amazing that after 24 hrs of no heat your house only dropped to 60!!!
I don't have all the answers, but do tenacious research, happy to chat anytime,
Good luck
Chris |
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PanelCrafters
Advanced Member
Posts:666
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| 24 Jan 2009 03:34 PM |
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Posted By mtfalen on 01/19/2009 6:40 PM
The total building load is 49000 Btuh, by zone, the main living area is 23400, second floor 15000, basement 11400. Thanks for taking the time review! What did you(they) use for the R-Value of the walls, and what was the design temperature(outdoor)? |
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....jc
If you're not building with OSB SIPS(or ICF's), why are you building? |
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Chris Johnson
Basic Member
Posts:465
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| 24 Jan 2009 05:57 PM |
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I spoke with a heating fellow I see on many a job sites, I explained your post and his comment was not in the product, but rather the set up or lack there of. Most HVAC installers are not setting up the system properly and he feels this is your issue. Call back the installation company and ask as to how they balanced the system. |
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Chris Johnson - Pro ICF
Napa, CA
Come for the wine, Stay for the ICF work |
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mtfalen
New Member
Posts:12
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| 25 Jan 2009 07:11 PM |
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So I had the service call this past Thursday. Chris, your suggestion was the very first thing that the tech advised....leave all zones at a constant temp, with even 2-3 degrees of setback I am forcing the system to work harder than it needs to. He also adjusted a few other settings to reduce run time, including the system intelligence setting that learns to come on early to reach desired temp by the programmed time, which now is not an issue as I've set for one constant temp. He also verified and changed the settings for the stages of the heat pump (low, high and aux). Usage since the visit has been more favorable but it also jumped up to 35-40 for a couple days! I think I need to look into this hybrid idea, it was not discussed at all :(
jc...
the R-value in the Manual J is 21-23
I don't see anything about temps, so if that was an input it doesn't seem to be displayed on the pages I have. It looks like all he gave me are the building load summary pages
There is a line that details Infiltration if that means anything to you, Winter CFM = 273, Summer CFM = 89
It also seems that the system is set for a rather frequent fan operation even when there is no heating demand to filter the air and help keep temps constant. The tech advised that the fan operation is not what is drawing significant power and recommended I keep that setting....any opinions on that???
Chris J., in terms of balance the tech said it will run in stage 1 for 15 minutes and then kick to stage 2 if not satisfying the demand. It will skip straight to stage 2 below a certain temp ( I can't recall) and cycle on banks for aux heat below 30 as needed....
I have a follow-up appointment set for 2/17 to see how electric consumption goes after the visit, I will continue to monitor dailiy.
Thanks to all of you for the help and advice....I think I need to explore this hybrid heat idea...
Mike |
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mlevendo
New Member
Posts:16
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| 28 Jan 2009 04:06 PM |
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Our situations will be very similar. My ICF house (in central Minnesota) will be finished in March. It is closed up now and is being heated by only the electric plenum heater (the heat pump will be hooked up in a couple weeks). My system is a Bryant air source heat pump with Eveolution control thremostat (same system as the Infinity just under the Bryant label). So far with just electric plenum heat it is costing me just a little more to heat the 3000 sq ft ICF as it does the 1000 sq ft 2x4 (early 80s built) home that uses electric baseboard heat. My HVAC installer has the same Bryant heat pump system I am having installed and he run his heat pump down to -10F, granted it will use some electric plenum to boost the delivered air temp. He also stated that the heat pump is most efficient when it runs for longer periods. He also stated it is best to leave the thermostat set at a constant temp. He leaves his set at 70F all winter long. A lot of people are not familiar with the newer air source heat pumps and think of the old heat pumps that were only efficient down to 40F or 32F. Even at 17F these new heat pumps have a COP 2. Going by my current electric usage my heat loss is less than 19,000 BTU/h at about -15F (this will go up a bit because that was figured when the whole hosue was set to 66F). This is much less than the 52,000 BTU/h that one HVAC bid had listed using central MN design temperatures. Please keep us informed on the status/resolution. |
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mtfalen
New Member
Posts:12
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| 28 Jan 2009 05:45 PM |
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I definitely will mlevendo. Kind of just in a wait and see for now until the follow-up service call. I am monitoring daily Kwh usage at the meter. It's very puzzling. This morning when I read the meter it was spinning faster than I've ever seen it spin. The motor on the HP was running but the fan was not turning nor was the tstat calling for heat. We had snow all night and then freezing rain at a temp of about 29 so I assume this was a defrost mode. In any event, the usage for the previous 24 hours was 230 Kwh with a average temp of about 20 and low/high from 16 to 23, so not too cold compared to recent weather and more importantly, not much variance. I did heed the advice to leave each of the three zones set at one constant temp. Possibly my problem is the program of stages. If aux heat strips are set to come on at higher temps than needed, maybe this is why I am experiencing such incredible consumption. I do expect to have the results of the blower door test and energy audit very soon which will confirm what I already know which is that leakage is not my issue here.... |
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dmaceld
Advanced Member
Posts:860
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| 29 Jan 2009 12:06 AM |
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Ask your HVAC contractor to give you a copy of the factory engineering performance data for the heat pump. It should be a table that lists outdoor temperature, indoor temperature, heating or cooling Btuh output, Kw power in. From that you can calculate the coefficient of performance (COP). What you will probably see is that the COP is close to 1 down at 0F. I looked for the tech data on the Carrier website but it's not available there.
Unless there is something fairly radically different in the design of the Infinity heat pump, compared to standard designs, you simply will not get much heat out of it a temps below 20F. That's why there's auxiliary heat strips in it, to provide heat when the compressor/condenser combo can't.
The factory data for my heat pump, a Daikin VRV-S, shows it will produce heat with a COP around 3 down to 10F. It does that because it has a variable speed compressor that runs at very high speed at temps near 0. The refrigerant doesn't pick up much heat each time it goes around the loop, but it goes around the loop many more times at 10F than it does at 50F. What sort of compressor does your infinity have?
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| Building house - what a way to spend retirement! It's done! We're living in it! |
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mlevendo
New Member
Posts:16
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| 29 Jan 2009 11:06 AM |
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During sheetrocking, tapping/mudding, and texturing they were using a torpedo heater due to dust and dirt in the air. On Dec 17,2008 the electric plenum was turned on (no heat pump) and my KWh usage for the 17th shot up to 225 and we were on the tail end of a -15F cold snap. On Dec 20th the KWh usage dropped to 165 and average temp was 10F. On Dec 26th my usage was 156 KWh with temps for that time perioid dipping to -5F and highs of 10F. On Dec 28th the KWh usage was 133 but the temp the day before climbed to about 25F. If the temps average about about 5F I use about 140 KWh for the day. When the temps dip down to -15F or bellow my usage spikes up to just over 150 KWh. We have to be in those -15F temps for for almost two days before I see the jump in KWh usage. All these stats are with the thermostat set at 66F for the entire house (right now there is only one temporary stat in the house). My project manager changed the temp last week to 55F so my usage has dropped. I put it to 60F on Sunday because installers are coming in to do flooring.
As for the heat pump, there are lockout configurations. Electric heat can locked out if it is above a certain outdoor temp. The heat pump can only move so much heat and as it gets colder it's ability to move the heat becomes less. You need to determine at what temp you want the electric plenum to assist the heat pump to give you acceptable delivery air temps. The installer should know this but I'm sure there will need to be tweaking.
The one thing you mentioned that may be wrong was you stated that the new settings would run the heat pump at stage 1 for 15 minutes and if the stat was not satisfied it would then kick in to stage 2. 15 minutes of stage 1 is probably requiring the plenum heater to assist it. There is a setting to force the heat pump to skip stage 1 and use only stage 2 if the outside temp is below a certain temp. Stage 2 will probably be able to supply the needed heat without having the electric plenum assisting it. Just make sure the stage 2 is not short cycling because that is not efficient either. My system is a 3 ton dual stage Bryant Evolution heat pump with a matching Bryant variable speed air handler and the Bryant 15K electric plenum heater. ARI certified specs for the heat pump with air handler are 19,400 BTUh at 47F and 12,800 BTUh at 17F. Granted that what ever the heat pump can't provide will have to be assited by the electric plenum. This depends on what you have the delivery temp set to. Specs show that at 17F the heat pump has COP of 2 which is 200% efficient. So at 17F 12,800 BTUh are being produced at 200% effiency. If more than 12,800 BTUh is needed at 17F then electric plenum will assit reducing the efficiency but it will still be more that 100% efficient. Obviously there is a point that the heat pump will drop below 100% efficency and all electric will be more efficient. My installer lives in Brainerd Minnesota and has his heat pump lock out at anything below -10F. |
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mtfalen
New Member
Posts:12
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| 29 Jan 2009 03:14 PM |
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Looks like I've got some more homework to do.....today was very strange, not much changed in terms of temp, stayed around 20 degrees but my usage was only 65 Kwh, which is the lowest I've seen yet. That, again is very puzzling.
Here are the specs on my system.
HP: Carrier Infinity 16 SEER, Model # 25HNA648A003 (4 Ton Puron, 2 stage)
Handler: Carrier Infinity FE4ANB005000 Variable Air Handler(Carrier Media Filter Unit)
Carrier Infinity Zone Damper Module SYSTXCC4ZC01
Carrier Infinity User Interface Tstat SYSTXCCUIZ01
Carrier Infinity Smart Sensor Tstat SYSTXCCSMS01 (2)
Carrier Infinity Motorized Dampers
I will work on pursuing some additional info on the performance data, etc.
I do know that it is set to skip stage 1 below a certain temp, I think it was 30 degrees, but I will confirm...
The fan setting has a low, med, high and auto. I assume auto is "as needed" for the heating demand and the low, med and high are for the continuous cycling? I was told that running the blower would draw only a small electricity use, any idea?
Here is my usage and average temp for the last 5 days
152 18.1
210 8.5
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112 12.3
225 19.7
67 20.7
The line represents where I changed the fan setting to auto, but the day before yesterday was crazy, that was what I described above when I said the meter was spinning faster than ever and HP motor was doing something, but the fan blade was not turning....
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mlevendo
New Member
Posts:16
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| 30 Jan 2009 10:36 AM |
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That may have been a defrost cycle when the meter was running so fast. The pump has to run in AC mode to heat/defrost the outdoor coil. Electric heat will be used to temper the indoor coil since it is running in AC mode. Make sure the heat pump is only doing defrost cycles when needed and not a setup schedule. performing defrosts when not needed will cause uneeded electric use.
Another thing I thought of was the electric plenum heater. Is it a modulating model? Maybe your electric plenum heater is going in a all on all off mode. Do your delivery air temps seem constant temp or do they fluctuate a lot? Heat pump deliver temps won't be hot like a furnace. Delivery temps can be 90F which will feel cool to the skin but still heat the house fine. If your delivery temps are real warm there is prabably to much electric heat from the plenum heater.
My unit is a 15k unit which is staged in 5k increments. It is a Bryant unit so it slides right in above the blower. It can add in electric heat in 5k increments as needed. I could not find any documentation on this unit on the Bryant website. I was originaly quoted the Warmflow II Select from Electo Industries. This model integrates with the Bryant Evolution Control/Carrier Infinity Control. I'm a little disappointed I did not get this unit. It stages in 500 watt increments which I would think would be a more efficient use of the electric heat. You set a delivery air temp and it will always assist the heat pump to deliver at a minimum of that temp. If the heat pump exceeds that temp then no electric heat is used. You can set this delivery temp on the plenum heater. There is also a setting that it uses to increase the delivery temp as the outdoor temps get really cold using a heat loss curve. Probably not as critical in an ICF home. The unit has a delivery temp sensor and an outdoor air sensor to know when to engage usein gthe heat loss curve. I did not know it I could post web links to the unit in this forum. |
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klemenv
New Member
Posts:20
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| 30 Jan 2009 03:06 PM |
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If you will ever put Yugo engine in your Ferrari, make sure it has at least twin Weber carburator :) BTW, do you know they are both linked to Fiat?
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mlevendo
New Member
Posts:16
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| 10 Feb 2009 09:33 AM |
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Any new developments?
My Heat pump will be hooked up by March in order to be grandfathered in on a program that my electric Co-op is phasing out. |
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mtfalen
New Member
Posts:12
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| 17 Feb 2009 10:43 AM |
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Sorry to be out of touch for a while. So I had another follow-up service appointment and all seems to be functioning as it should. I also played around with shutting off and turning on all breakers individually to ensure that there weren't any issues with phantom loads or wiring problems elsewhere and that was all ok. So my load is definitely coming from the furnace and heat pump. Since the Jan 22nd service call I saw considerable improvement. The key changes there were in the programming of the stages and setting to one temp for each zone and not changing. Prior to that service call is was averaging around 200 Kwh per day, and temps were all over the place with some very cold days around 0 F in January. Since then I have averaged 120 Kwh per day with an average temp of 27 F. So obviously the milder temps have quite a bit to do with the decrease. So I guess that's it for now, just going to continue to watch and evaluate as we get into the warmer Spring months, I just can't help but wonder if my investment in this Carrier product was worth it or if I would have gotten the same performance from something much cheaper. OR Is a gas backup more approriate? ....... |
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