Discussion in 'General Discussions' started by TuffToodle, Nov 29, 2018.
Also I thought energy audits include heat loss calculations...
Yeah we definitely have never had anything that thorough done! They must have used their modeling software to calculate the btuh in our report. By inadquate duct work, what do you mean?
Tell them to show you the numbers and if inadequate they need to upgrade your heat pump for free. That's if there is nothing wrong with the system. Could 2 techs be wrong? Certainly. I would get a manual j done before you do any insulating and take them to court if it's not fixed.
I mean the duct work might be too small for a 4 ton.
You do make a lot of determinations without knowing any facts here....
To "TuffToodle", we do not know the loads, a manual J does not help much at this stage, since we would have to guess the current insulation values, and the air infiltration. We only have the information that the house is very leaky as indicated by a blower door test, suggesting a large amount of air infiltration, and ducts in the uninsulated attic. Are the ducts in the attic insulated?
We would need the brand and model# of your heat pump, and the brand and model number of your water pumps. Any other information you can post here would help as well. Pictures of your system in the basement would be great. Is your aux heat still off? How many tanks do you have? Pictures.....!
How is your current heating? Does the system keep up with the thermostat settings?
Post this here, so we can start in an orderly fashion to assist you.
I will do my best to try and answer all your questions. I am not well versed in the system, but I can dig through my paperwork to get you answers. Please just let me know if you need more info.
According to our insulation quotes we have about an R19 in the attic – though this is spotty as some places in the attic you can see straight through to the drywall. We know this is an issue.
I have a Trane T2GN split dual capacity heat pump with intellistart, a Trane TAMG variable speed air handler with electric heat packs and Aprilaire air cleaners, and an Arzel Zoning package to separate the first and second floor with Honeywell thermostats. I also have a 50-gallon electric water heater and a 50-gallon geothermal desuperheater that has been turned off by the installer for the winter. Both tanks are located in the uninsulated garage (though we did wall off the mechanical room to start remedying that situation).
The ducts in the attic are insulated. The emergency heat is still turned off.
I have attached the documents I received when the installers were designing the system - I'm not sure if this included a manual J (I have asked for those documents and am waiting to hear back) or if they just used average numbers for our area.
I have also attached the photos taken by our energy auditor, which should include more specific information (model numbers) of the system components.
Thank you all for taking the time to help out. I am desperately trying to dodge another $700 January!
It gives the BTUH but that doesn't prove they did the actual manual J. If you didn't see them do it, they did not. I would try turning off the HWG (hot water generator). That should help a tad. HWG will cost you 10% of your heating capacity during winter. Summer is almost free. Your installer should be able to turn it off for you.
Is that the same as the desuperheater? If so, he turned it off when he came out during our last visit for exactly those reasons
Yes it's the same. Looks like it's still undersized for your load.
If we determine that it is undersized - what portion of the system would need to be replaced?
If it's duct work, that will need to be upgraded. I'd say new heat pump, maybe add more loops to the ground to handle the new HP tonnage. Get a manual J done and compare the numbers to your data that you uploaded. If all that is not feasible, concentrate on better insulating your home.
Well I guess I better get to the bottom of the issue then, because all that will certainly not be fixed without a lawyer How would I know if the duct work was undersized? I am waiting to see if the installer will send me the Manual J papers from the install. Who do I contact to have another done? Any HVAC company?
You'd need an hvac guy for the duct work. Energy auditor will do the manual J. Not sure why you didn't get one last time they were out.
Larger ductwork is not changing the amount of BTUs (Heat) which is put into the house via the geo system. You might have lesser noise, use lesser electricity for the blower, or lesser balance between different rooms, but the heat pump will not change the amount of heat it puts out, just because the ductwork is being changed.
Manual J does not make sense when you are in the middle of remodeling and adding insulation anyway. A calculation does not help you right now.
What you need is a skilled energy auditor who can see where the air infiltration comes in, or where the weakness of the insulation is, and know how to fix it.
With remodeling, I assume you are going through a permit process anyway, and you are obligated to remodel the space according to the energy code in place for your jurisdiction. If your space is leaky and you did not address the leaks, a lawyer won't be able to help you. To exemplify this, if you leave the window open, and you allow cold air to infiltrate your house, you can't blame the heating system if it can't hold up, from a legal perspective. Close the window, e.g. find the spots which are responsible for the heatless, and address them.
Thank you so much for that explanation. My biggest question has been - is it really possible that a $700 winter heating bill is due to poor insulation and air sealing alone? It just seems awfully high. When we had the insulation consult our estimated energy savings were projected to be about $80/year. So what about the other $620 I'm paying in January? It seemed like the colder it was outside, the higher my bill - and so I naturally assumed my problem is with the heating system. At this point, I am wary to throw money at insulation hoping to fix the problem to only find out after paying for it that it wasn't the answer I was looking for. I keep hoping for some sort of Aha! moment where I can tell exactly what the issue is. I've attached the bar graph from my electric company from last January, all of this is complicated by the fact that I have solar panels - so the warm sunny days my generation helps to offset my usage, skewing the graphs a little. Either way, my heating costs right now are about double what the design software projected. I hope it really is just insulation, I guess I just won't know till I suck it up and do it.
Side note: Shouldn't the geo system have been designed for the house we had - not the one we were dreaming of? The Manual J should have been done to calculate the load for our leaky house regardless of the remodel, right? We are doing the remodel ourselves so I wouldn't presume perfect air sealing as we go along - though we try to make improvements where we can (as we learn)
I would be looking at the thermostats and how they control the heat packs in the air handler.
I haven't heard you say "the heat can't keep up when it's cold". At some point the electric heat packs are turning on to help reach set point on tstat.
Try to figure how to disable the heat packs. Go into the tstat settings, see if you can tell when the electric heat is programmed to turn on.
When I had a heat pump with aux/emergency heating, the tstat wouldn't turn on the aux until the room temp slipped back 3 degrees below set point.
I don't seem to have any problem with the heat keeping up in the winter - we are on a slab so the floor is chilly, but the air is warm enough. I have been reading through the thermostat manual and poking around the controls, but there doesn't seem to be any indication that I can adjust the aux heat at all. It is my understanding that whenever the temp dips below a certain magic number somewhere around the freezing mark, the aux heat will have to kick on. This is why January-February is my headache months - we spend most of the month in that zone so I can only assume I am running aux heat most of the time. Luckily we've had a warm winter so far, but it's only a matter of time. I wasn't as well versed in the system last year, but I will be paying a lot more attention to when I see aux heat on the thermostat - not that there is much I can do about it
Check into the manual for the Air handler and the zoning unit.
With a geo heat pump there is no reason to have the aux heat operate by outdoor temp. That is usually used in air source heat pump systems.
Again I would look for a way to disable the aux heat.
ChrisJ and NC73 are absolutely on the correct path to your solution. Forget manual J, duct sizes and lawyers for a minute and concentrate on finding out whether or not your heater strips (AUX heat or EMERG HEAT) are operating in the cold weather. I've been following this thread (lurking) for a while now and I can't believe you still do not have concrete knowledge yet as to whether or not they are ON in the cold weather. Sorry for those words, but that is truly step #1, and would explain sky-high bills. You mentioned in an early post that you have a switch in the garage to turn off the strip heaters. Does that switch work?
It is entirely possible that your GSHP system is properly sized but it is not getting the chance to run hard in the cold weather because the installer didn't put in the proper thermostat, or does not know when AUX/EMERG heat should actually come on. Or maybe the t-stat and settings are right, and you defeat all that by turning the thermostat to far down at night and when you do a morning warm-up, the electric heat is on full force. A simple staging setting on the correct t-stat could be answer to your high bills. I hope I didn't come across as being a jerk. I want you to have a system that works and you paid a lot of money for it, so I didn't mean to pile on.
Thanks for pitching in SR - to clarify: The emergency heat has a switch in the garage - we never touch it - the emergency heat is OFF. However, the aux heat (which uses the same strips but partners with the heat pump, unlike the emergency which is strictly strips) comes on occasionally as needed. The only indication I have that the aux is on at the moment is if I happen to pass by the thermostat and see the "aux" label displayed.
As for the outdoor temp affecting my use of aux heat - well of course it does! At some point the house is losing heat at the same rate it is creating heat with the geo pump and needs to be supplemented with the aux strips to keep the cold at bay. Correct?
I am sorry if I seem naive - I knew just enough to have the system installed, but not enough to troubleshoot it lol.
Thanks again for all the help.
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