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JillF
New Member
Posts:26
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| 01 Jan 2009 07:52 PM |
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Thanks for the info! I guess I was hoping that the geo would be more of an "instant savings" than it is, especially because it was so expensive to install. Do you know how many tons your system is and how much loop you have in the ground? We're 2400 sf of house and only keeping the place at 63 degrees with 8 tons of system and 765 feet of loop buried in our front yard. I'm wearing two sweaters and a fleece -- it's pretty chilly around here tonight! |
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robinnc
Advanced Member
Posts:586
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| 01 Jan 2009 07:56 PM |
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I'm no expert but that seems insane to have one ton for only 300sf. How did they come up with that kind of tonnage? Pros?
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JillF
New Member
Posts:26
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| 01 Jan 2009 08:01 PM |
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I don't know how they got that number, although we had a couple of different guys bid on the job and they all had the same tonnage. It's either because our house has a big heat load because of the way it's built (a lot of windows & doors) or maybe some other reason that is more technical. But, yeah, it does seem like a lot. |
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Palace Geothermal
Veteran Member
Posts:1609
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| 01 Jan 2009 08:15 PM |
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I am with you Rob,
A 2400 sqft house with an 8 ton system and only 800' of vertical loop doesn't make any sense at all.
8 tons seems too much for the house and 800' of loop is not enough for 8 tons. |
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Dewayne Dean
<br>www.PalaceGeothermal.com<br>Why settle for 90% when you can have 400%<br>We heat and cool with dirt!<br>visit- http://welserver.com/WEL0114/- to see my system |
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JillF
New Member
Posts:26
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| 01 Jan 2009 08:19 PM |
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That's what I've been wondering about -- the loop-to-ton ratio. But to add more loop will cost a lot of money. If the EWT is good, does that mean the loop might be big enough?
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engineer
Veteran Member
Posts:2749
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| 01 Jan 2009 08:23 PM |
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Doing some math here:
$250 / month electricity for heat at $0.15 per kwh works out to 1666 kwh / month or 55 kwh / day. I don't know which Water Furnace models you have but Envision 049 in high stage with 30 deg entering water uses about 3 kwh. Doubled that's 6 kwh. 55 kwh / day works out to 9 hours operation per day. If two 4 ton heat pumps are running 9 hours per day in a 2400 SF house and it won't get above 63 deg, there is some major problem. Jersey just isn't that cold.
Any geo / HVAC contractor able to fog a mirror, see lightning and hear thunder ought to be able to shed light on this. If the units are ducted and installed correctly then the house is in serious need of an audit and weatherization.
We do need your EWT - a ten dollar digital cooking thermometer (be sure it ranges down to 0 degrees or less) strapped to a metal fitting on the incoming loop water line and crudely insulated with a wrap or two of a dry rag should get close enough for now - let us know. |
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Curt Kinder <br><br>
The truth is incontrovertible. Malice may attack it, ignorance may deride it, but in the end, there it is - Winston Churchill <br><br><a href="http://www.greenersolutionsair.com">www.greenersolutionsair.com</a>
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Palace Geothermal
Veteran Member
Posts:1609
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| 01 Jan 2009 08:24 PM |
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Posted By JillF on 01/01/2009 8:19 PM That's what I've been wondering about -- the loop-to-ton ratio. But to add more loop will cost a lot of money. If the EWT is good, does that mean the loop might be big enough?
Yes If your EWT is above 35° or so you are not too bad of shape. Whatever it is, it will continue to drop as the winter weather continues. Ideally the loop will get down to about 30° at the end of the heating season not in the middle.
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Dewayne Dean
<br>www.PalaceGeothermal.com<br>Why settle for 90% when you can have 400%<br>We heat and cool with dirt!<br>visit- http://welserver.com/WEL0114/- to see my system |
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JillF
New Member
Posts:26
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| 01 Jan 2009 08:33 PM |
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Thanks. I'll get the EWT. It seems as though that's the answer. Also, the kwh costs are likely on average closer to 11 cents per kwh. We have a meter that charts on-peak and off-peak usage. Off-peak, we pay only 7 cents. Our WF units are the Envision series -- the latest model. |
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arkieoscar
New Member
Posts:57
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| 01 Jan 2009 08:35 PM |
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My 1 ton console has 2/400 loops and the 2 1/2 ton has 4/400 loops. The EWT for the console is back up to 45 after dropping to 42 during the very cold spell we had after Thanksgiving. I'm not going to check the large unit. It's in the crawlspace and I haven't been down there since June. |
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JillF
New Member
Posts:26
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| 01 Jan 2009 08:37 PM |
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How do you check the EWT on your units? If it's low, is there any way to raise it other than adding more loop? Thx.... |
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engineer
Veteran Member
Posts:2749
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| 01 Jan 2009 08:47 PM |
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OK, since the power is cheaper than .15, then your run times are likely significantly longer - given that you've disabled aux heat and can't get above 63 deg, that makes some sense. Still need your EWT - if it is low then units' capacity is substantially reduced, though that still doesn't explain why so much tonnage.
Envision performance table allows EWT down to 20 if flow is sufficient, and a safety cut out stops compressor at 15 deg. COP is still > 3.0 at 20 EWT, but capacity is severely reduced. |
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Curt Kinder <br><br>
The truth is incontrovertible. Malice may attack it, ignorance may deride it, but in the end, there it is - Winston Churchill <br><br><a href="http://www.greenersolutionsair.com">www.greenersolutionsair.com</a>
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JillF
New Member
Posts:26
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| 01 Jan 2009 08:58 PM |
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It's possible that the tonnage is because of the design of my house. It was built by my parents and there are some unusual things about it:
1. It sits off the ground, on stilts (a requirement when it was built bc the zoning board was worried about drainage around the property)
2. It has high ceilings in a few of the main rooms, with the heat coming out of the ceilings and not a lot of returns down below.
3. It's got a lot of big windows. In fact, the main rooms are probably 30 -50% glass.
4. There's another wing of the house (about 1,000 sf) that is heated separately, by a non-geo heat pump (very ineffecient). This wing isn't used much, so we generally keep the heat down very low (about 45-50 degrees). Still, that's a bit of cold air separated from the main part of the house only by an interior wall.
All this may have given the place a high heat load requirement. I know the installer used the Manual J calculation. |
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Palace Geothermal
Veteran Member
Posts:1609
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| 01 Jan 2009 09:04 PM |
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Jill,
Certainly all of the items you mentioned would increase the heat load of your house compared to a more normal type of construction.
With the heat registers in the ceilings, most of the heat could be staying up there. Can you check the air temp at the ceiling level compared to the floor? |
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Dewayne Dean
<br>www.PalaceGeothermal.com<br>Why settle for 90% when you can have 400%<br>We heat and cool with dirt!<br>visit- http://welserver.com/WEL0114/- to see my system |
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JillF
New Member
Posts:26
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| 01 Jan 2009 09:08 PM |
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That's a very good idea. I'm going to get temps for the air closer to the ceiling and for the EWT on the units. Although once I get all the info, I don't know how much I can do with it. We really spent all we could to install the geothermal. There isn't much left to fix it if it's broken. |
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Palace Geothermal
Veteran Member
Posts:1609
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| 01 Jan 2009 09:21 PM |
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It might be all you need is a ceiling fan |
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Dewayne Dean
<br>www.PalaceGeothermal.com<br>Why settle for 90% when you can have 400%<br>We heat and cool with dirt!<br>visit- http://welserver.com/WEL0114/- to see my system |
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joe.ami
Veteran Member
Posts:4377
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| 04 Jan 2009 08:57 AM |
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I'd be interested to know what conclusions the independant manual J calculations yielded. This quantifies your requirements. 8 tons does seem high at a glance and you are asking for a relatively low Delta T, so we might agree that there is a problem unless your heat load calcs suggest a large load.
See if you can find out what the BTU requirement suggested by all bidders was.
What does the installing contractor have to say about all of this; how did his refererences check out?
Good Luck,
Joe |
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Joe Hardin
www.amicontracting.com
We Dig Comfort!
www.doityourselfgeothermal.com
Dig Your Own Comfort! |
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JillF
New Member
Posts:26
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| 04 Jan 2009 12:25 PM |
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Thank you for your suggestions. I'm going to be following up with the installer and Water Furnace this week, and I'll try to find out about the BTU and head load calcs. Possibly, we have a large load because our house is built up off the ground on piers (drainage thing, zoning board issue when house was built) and it has a lot of big glass windows and glass doors. We chose the installing contractor because he was highly recommended by our regional Water Furnace Territory Manager. Seemed like the best way to go at the time. But since then, the guy hasn't been much help. I'm waiting to see if Water Furnace picks up the ball here or not. Will post results from conversations to come next week. Thx again. |
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tuffluckdriller
Advanced Member
Posts:630
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| 05 Jan 2009 10:37 AM |
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Is the duct in the attic insulated? This might be a huge loss point. |
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| Clark Timothy ([email protected])<br>Geothermal Heat Pumps: Heating and Cooling that's Dirt Cheap!<br>www.pinksgeothermal.com |
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geo fan
Basic Member
Posts:408
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| 05 Jan 2009 06:54 PM |
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I have noticed increased snow melt on the roof ( at my parents ) the ducts are all 3 inch wrap, R-8 insulation
Im planning to cover all the ducts with R-30 batt with no vapor guard, I think because of the extended run times even with max available duct insulation, loss is still substantial |
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