Hello and well met,
I am writing to all to ask for assistance in what I need to do to fix a major problem. I will try not to be too wordy:
We added onto our 50+ year old house that was 1800 sq ft with an old electric furnace, roof and windows were very old as well. Windows were single pane glase. Single family ranch on a slab. We added on an additional 1600 sq ft on a slab. Replaced all the windows, roof, siding and insulated everything (insulation in the old house was great) with energy efficient products. The original house is made out of Cynder Blocks.. yep you heard right. New part, Wood and vinyl. We installed a 6ton waterfurnace geothermal close loop system and took out our old system that was as big as a suburban. In short, our bills went from roughly $180/month in both winter (70 degrees) and summer (71 degrees) to $800 in the winter and $300 in the summer keeping the same temperature on the new unit. This is INSANE.
So I know that the installation needs some work and I will give you what has been discovered, but in short why are the bills too high.

1. We noticed we only have enough loop for a 5 ton unit. We will be drilling and tying in another loop to suffice for the 6 ton unit. The new HVAC company says the loops shouldn't matter in the summer to cool the house, but we are about 130 ft too short with loop.
2. The HVAC company that we used went out of business after being around for 38 years (getting no help there)
3. The new HVAC company says that we need 8 ton sytsem to heat the house, but cooling shouldn't be an issue regardless of the loops. The 6 ton isn't enough.
4 We have 4 verticle loops that are 200ft each. Shold have more feet than that, but we need to drill one more well to match the other 200ft loops that are already installed.
5. Our air the main supply to the house of our new furnace has serious condensation on vent of the first foot above the furnace as it comes out. Why?
6. Nothing is zoned.
7. My system to run in summer is always running on zone1 & 2
8. My system in the winter is running on Emergency heat (i know this is expensive, but why is the heat $800 and not lower like my older furnace)?
9. We don't have a humidity problem, I don't think, but since there is condensation on the unit should I get a dehumidifier?

So what should I do, or can I do to get my costs down. My neighbors and inlaws and friends tell me their 2 story houses elec bills are around $150/ month on regular elect for a 2500 sq ft house. Yes they are smaller houses that are verticle, but the difference in cost is WOW. We replaced everything (windows, roof, insulation, geothermal) and bills have gone up 3-4 times.

Thanks for the input.

Regards-
C

Posted By cad10047 on 18 Jul 2010 10:21 PM
We installed a 6ton waterfurnace geothermal close loop system and took out our old system that was as big as a suburban. In short, our bills went from roughly $180/month in both winter (70 degrees) and summer (71 degrees) to $800 in the winter and $300 in the summer keeping the same temperature on the new unit.

2. The HVAC company that we used went out of business after being around for 38 years (getting no help there)

4 We have 4 verticle loops that are 200ft each.

8. My system in the winter is running on Emergency heat

Regards-
C

Not much information to help us; help you. The troubleshooters check list identifies info we need to help.
If your loops are too short, not much can be accomplished with out fixing that first.

RE zones, a well designed system works fine without.
RE condensation, cold metal in damp basement will do that, dehumidifier will stop that.

Good Luck,
Joe

Hi Joe,
I appreciate the response, good information.
I have a couple of questions I am hoping you can respond too:

1. With the short loop, does that effect cooling? I know if effects heating, but the new HVAC company says cooling shouldn't be effected. I find that weird.

2. Dehumidifer.. is this a good thing to get and help with the unit and our house for cooling? We live in a humid area. We don't have a basement, but the outside area is always high in humidity.

3. If we get our additional loop, should that (hoping here), help dramitcally or do you think this would be marginal difference?

Thanks,
C

Posted By cad10047 on 18 Jul 2010 10:21 PM
In short, our bills went from roughly $180/month in both winter (70 degrees) and summer (71 degrees) to $800 in the winter and $300 in the summer keeping the same temperature on the new unit.

8. My system in the winter is running on Emergency heat (i know this is expensive, but why is the heat $800 and not lower like my older furnace)?

This is the key point IMO. Before we even talk about loops, system size, etc, we need to figure out how this could possibly come about. Absolute worst case, if the system is on emergency heat 100% of the winter, it should cost you the same as straight electric heat. It sounds like you roughly doubled the size of the house, but you also added insulation and tightened the envelope, so your energy use should probably be somewhat less than double the original. Instead you appear to be using 4-5X as much energy.

Regardless of what is going on with the heat pump, this is not a reasonable number. Some possibilities come to mind (in no particular order of liklihood):

-Massive envelope problem, like return air coming from the outside or windows left open all winter
-Radiant heat in an uninsulated slab
-Huge parasitic load related or not to the geo system, i.e. a grossly oversized loop pump wired to run 100% of the time. I think one case where high bills were reported on this forum turned out to be due to a livestock water tank heater that was drawing 1500W all winter.
-Actual usage vs billed $ - could your electric rate have gone up 4X (maybe you had a special rate previously for the electric furnace?) - Do you have kWh usage #s by month? Estimated or actual? My electric company uses a horrible algorithm for estimating usage - unless I send in my meter reading each month they are usually off by 50-100%.

Given the issues you describe, you're right, something is seriously wrong.
When you say "electric furnace", do you mean a furnace that only has electric heating coils in it, or are you thinking about a heat pump, with an outdoor compressor that does heating/cooling? There's a huge difference.

I often see problems with additions because of very leaky construction. This would also lead to excess indoor summer humidity which would exacerbate the sweating you see on your sheet metal ducts. However, as Joe notes, condensation on sheet metal ducts is common.
Many builders confuse insulation with weatherization. If they didn't pay attention to making the addition tight, then all that insulation may be doing you little good.

Where do you live? Your climate has a huge amount to do with the comments we might give you.

Your best bet on the home construction end is going to be to start with a detailed home energy consultation. A blower door test and thermal imaging will home in on the exact locations of issues with the construction. A good energy person will also be able to do some basic measurements on your geo system to see if it appears to be behaving properly or not. You can weigh this information along with your HVAC contractor. It's often good to get an independent opinion on these things.

A few construction red-flags. If your addition has lots of recessed lights, especially in cathedral ceilings, that's a likely problem spot. Also, new windows are often installed improperly and leak worse than the originals. Any connections between the home and the attic spaces - hatches, doors, pull-down ladders, etc. are suspect. If they are not insulated and air sealed, then they're going to be responsible for excess heat loss in the winter.

Address these issues before jumping into a dehumidifier. Dehumidifiers heat up your house during the summer and suck power, driving your electric bills higher. If your air conditioner is running properly and your house is tight, you should not need additional dehumidification. If your house is leaky, then the air will likely always be uncomfortably humid if you live in a humid climate.

Good luck!

An $800 winter heat bill suggests too much aux strip (electric resistance heat) operation. While strips are an integral part of the sizing of systems in heating-dominated climates, they shouldn't have to run except during extremely cold days.

Any statement of required tonnage should be backed up by a detailed load calculation, not by hand waving or reliance on rules of thumb.

Posted By cad10047 on 19 Jul 2010 10:18 AM
Hi Joe,
I appreciate the response, good information.
I have a couple of questions I am hoping you can respond too:

1. With the short loop, does that effect cooling? I know if effects heating, but the new HVAC company says cooling shouldn't be effected. I find that weird.

2. Dehumidifer.. is this a good thing to get and help with the unit and our house for cooling? We live in a humid area. We don't have a basement, but the outside area is always high in humidity.

3. If we get our additional loop, should that (hoping here), help dramitcally or do you think this would be marginal difference?

Thanks,
C

It's not that short loops don't affect cooling. It's that in a heating dominated climate you need less cooling so loops are sufficient for that task.

My dehumidifier comment was directed towards a basement application. If your system is within conditioned space and this occurs, we have much more research to do.

Right sizing loop field could be a dramatic difference. There is much we don't know yet about your home and situation.

I agree with some of the other concerns and questions. Especially clarity of the old system. Was it truely all electric or gas/oil electric?
Joe

I would allso add there is much we do not know about your loops or circulator yet, region of the country, lithology of the hole?
Eric

To all,
Thank you very much for the feedback and keep it coming. I am going to try and answer most of the questions and issues as best I can as I am not versed on the jargen:

When I say electric heat, I mean the emergency "strip" that the waterfurnace runs on. So basically bypassing the loops and using nothing but electric. What was interesting, the house couldn't even stay heated with that running. This was at our coldest winter days in a long time. We were at zero degrees Far. and couldn't keep the house heated about 62degrees.

Our furnace isn't in a basement, our house is on a slab. The furnace is on the main floor of our ranch style house, we only have one extra room on the second floor, in our laundry room.

We live in St Louis, Missouri. Very Hot and Humid Summers. 95*+ temps with very high humidity. Winters are very cold, not a lot of snow.

We have been told we need prob 8ton of furnace (2x 4 ton unites) to heat our house properly. Howerver, the HVAC company says the new 6 ton unit (even with 5 tons of loop) should suffice for cool.

As for a "tight", the main supply seems to be leaking. i am no professional, but it seems that air is blowing out of the seam around the connection between the Furnace and the Duct work. Also, most of the main is insulated with a thin silver like insulation. Well that is filling up with air as the insulation wrap is puffing out. So I know that is an issue. Most of the main runs through the "attic" space which is very hot.

Windows seem to be tight. No wind gets in, as far as I can tell. We don't have vaulted ceilings, but we have canned lights. The insulation around the lights has been blown in up to 12 inches. Cans are also insulated for electrical safety.

I know that we need another well. We also need to fix the leak for the supply line (even though that leak is minimal). But other than that, I imagine I should get the system serviced. We are waiting for the extra well before doing this. Hopefully that will help. As for a dehumidifier, I am not worried about the elec bills at this time. As they are $300 what is another $20. If it possibly helps with the running of the system, why not?

Thanks again-

C

cad10047,

We would like to offer our assistance in facilitating a resolution.  Please provide the model number, serial number, and the name of your installing contractor so that we may look into your inquiry further.

WaterFurnace International, Inc.

You mentioned the main heat runs are in the attic... is the duct work in the attic area insulated? Insulating the duct work properly will help out a lot. Also where you had seen condensation on the duct work, insulating it there too will help eliminate condensation to form on the outside of the sheet metal.

If you were to totally turn off the electric back up strips, what temp. would your house get up to in the winter? My parents have geo-thermal and their electric back up heater strips were coming on when they weren't supposed to. They turned them off and their electric bill dropped a lot.

The new geo contractor mentioned you need a 8 ton unit, that seems really high for that size of house... did he do a manual J calculation to determine that?

I think I would try the easiest and least expensive options first, before adding another loop and bigger unit. Also as mentioned by others, have an energy audit done with a blower door test and thermal imaging to determine if there are air leaks and lack of insulation. I believe the energy auditor can also suggest the size the HVAC should be.

Posted By cad10047 on 19 Jul 2010 10:18 AM
If we get our additional loop, should that (hoping here), help
dramitcally or do you think this would be marginal difference?

Sorry to say, I'd expect that going from 4 to 5 bores would make
only a small difference, if any. Suggest you have an energy audit,
Manual-J load analysis, and professional system diagnosis before
experimenting with expensive "fixes" that might not address the
problem.

I concur with looby.  Adding another loop will lower your ewt and increase the output of the machine, but the question is how much.  If you collect data on system now you should be able to easily project the outcome of adding another loop without the expense of "trying it"

Yep. This is a good opportunity to get it right the second time (so there will be no need for a third try).

It isn't possible to get a geothermal unit to be less efficient than an electric furnace no matter what is wrong with it. OK, maybe if it is cycling between heat and A/C - or something else changed.

When I asked about the "electric furnace" I was referring to the old unit, not the new system.
Was the old furnace electric only?
j

Thanks again for all you questions and info, I will do my best to answer:
Doing an Energy Audit I think is an excellent idea. Does anyone have a contact of anyone that can point me in the right direction for the St Louis, MO area. I am having trouble finding one.

As for old furnace, it was Gas and in the attc. We brought it down to the main floor and went Geothermal. The new system was completely installed and running Nov 09. Our winter was very cold, couple weeks at zero degrees. This is our first summer.

Ducts work is insulated in the attic. There is about 1-2 feet just above the furnace where the main supply comes out that isn't insulated , but that is about it.

If we turn off the electric stips, the house coudln't get about 59 degrees when it was zero out. When it was 20 degrees it could get in the mid 60s. In the summer, right now, with mid 90s, we can get the house cooler than 76 degrees. So here is the weird part, when we talked to our original HVAC guys they said turn on the back up heat, or Electric emergency strips, to warm our house. When I did manual overide, the system coulnd't warm the house into the 60s either. But when the system cycled from Stage 1 & 2 and automatically moved over to emergency heat, we could get the house to about 69-70 degrees max.

My furnace is a Waterfurnace Envision and the HVAC specialist says it is a 6 ton.

The new HVAC company did do some kind of heat load. I gave them plans to my house and they came back and said the cooling should be ok ( and kind of concerned about the cooling) but said no way on the heat. Something like the new system has 85000 btu (or whatever the termanoloty is) and we need about 105000 btu ish. So u see the delta. He said you need about another 2 tons. We aren't going to buy another system, btw. So we need 8 tons total, so instead of a 6 and a 2 ton. He thought 2 4's. We just have the 6 ton now.

Right now my current HVAC company says drill another well, service the current sytem and insultate some of the duct work and that should help "A LOT". for the summer months. As for the winter, lets see what happens, maybe do some zoning time stuff.

Thanks again for all you questions and info, I will do my best to answer: Doing an Energy Audit I think is an excellent idea. Does anyone have a contact of anyone that can point me in the right direction for the St Louis, MO area. I am having trouble finding one. As for old furnace, it was Gas and in the attc. We brought it down to the main floor and went Geothermal. The new system was completely installed and running Nov 09. Our winter was very cold, couple weeks at zero degrees. This is our first summer. Ducts work is insulated in the attic. There is about 1-2 feet just above the furnace where the main supply comes out that isn't insulated , but that is about it. If we turn off the electric stips, the house coudln't get about 59 degrees when it was zero out. When it was 20 degrees it could get in the mid 60s. In the summer, right now, with mid 90s, we can get the house cooler than 76 degrees. So here is the weird part, when we talked to our original HVAC guys they said turn on the back up heat, or Electric emergency strips, to warm our house. When I did manual overide, the system coulnd't warm the house into the 60s either. But when the system cycled from Stage 1 & 2 and automatically moved over to emergency heat, we could get the house to about 69-70 degrees max. My furnace is a Waterfurnace Envision and the HVAC specialist says it is a 6 ton. The new HVAC company did do some kind of heat load. I gave them plans to my house and they came back and said the cooling should be ok ( and kind of concerned about the cooling) but said no way on the heat. Something like the new system has 85000 btu (or whatever the termanoloty is) and we need about 105000 btu ish. So u see the delta. He said you need about another 2 tons. We aren't going to buy another system, btw. So we need 8 tons total, so instead of a 6 and a 2 ton. He thought 2 4's. We just have the 6 ton now. Right now my current HVAC company says drill another well, service the current sytem and insultate some of the duct work and that should help "A LOT". for the summer months. As for the winter, lets see what happens, maybe do some zoning time stuff.

Regards-
C

How much gas and at what cost did you consume before the change?

Do you know the btuh capacity and efficiency of the old furnace?

Our orginal house was about 1600 sq ft and we added an additional 150 sq feet. Our bills with a combo of gas in the winter and elec in the summer were never over $200 either side. That was the extreme. Usually bills around $140 total. Now we did add more sq footage, but we also replaced the room, more insulation and replaced all the single pane windows with thermal vinyl windows.