Discussion in 'General Discussions' started by sixmm, Apr 12, 2011.
Would be nice to know the heat loss/gain calcs for this house.
Sorry for not being more involved in this thread. Last week was killer busy.
The 4000 Sq ft does not include the basement. We are putting in a story and a half.
Annual total heating load is calculated at: 164 MMBtu
Annual total cooling load is calculated at: 89 MMBtu
Do you know what your heat loss number is at design day? Where are you located (closest major city)?
I am in Kansas City.
I am not sure what your asking with your other question.
Paired with KC weather data, your annual load indicates around 120KBTU/h at -5F design temperature. This appears to be extremely high for a well insulated new built house and appears to be the root of the problem. Your heatloss calculation appears off, invest the money and hire someone for a couple hours or buy a program to do it yourself.
I ran some quick calcs, even calculated with generous windows and door area, a new built house of 4000 sqf in KC does not run over 90kbtu/h (with 20 ft ceilings etc). In any case, 6 tons would be just fine....
for my own knowledge, how do you calculate a design day heat loss using yearly heat load?
If that heat load is accurate, you might wanna consider insulation in the design of your home
It is way high.
My understanding is that this is a new built house...almost impossible to have that load with an up to code building of 4000 sqf
Most programs show you the heatloss in BTU/h at design temperatures, and then you they match it with heating degrees or BIN data for you location to see the actual BTU need for the heating season. So for KC 164 MBTUs actually ends up to be around a 120 KBTU load at -5 degrees outside and 70 F inside setting.....crazy high for a 4000sqf new built. It should be anywhere between 70-90 KBTU, depending on the insulation effort, and with most of the house being forced air with an easy auxheat, not require more than a 6 ton system. Don't know the layout, so it is either a 1 or 2 HP system. The heatloss suggests that either it me missing something and not getting the whole story, or the heating contractor has not much experience in sizing geo systems.
It could be all three. Just did a retro/addition heat loss for 3700 '2 in Avon Ohio and got 87,000 on design day here. 72* and -10* at 40 MPH off the lake.
I am new on this forum. Here is where I am on a retro in my house in middle TN.
1472 sq feet.
Model 026 Tran. 27.....estimated at $5K...I am waiting on quote.
I just met with the driller. one 300' hole with geo clips.....$4K
I will do some duct changes and misc stuff...$1K
This comes to $10,000. Minus tax credit of $3,000
This leaves $7,000.
My old Heil Quaker dual fuel package is near the end of the road.
Replacement cost...Estimated at $3,000
This makes my cost to replace with GEO to be $4,000 more than it would cost to replace my Dual Fuel unit.
$10,000-$3,000-$3,000= $4,000 real excess cost to install geo.
If I save only $60 per month, this is much less than the propane for the dual fuel unit, I will have "payback", yeah I don't like that word either, in about 6+ years.
But you could say, where can I get $700 per year for a $4,000 investment.
Does this make sense???
Absoloutely makes sense. Glad your retro fit is a go. I was never so happy as the day I pumped out my oil tank and sold it.
The math looks right to me. I call it incremental (or additional) cost to go geothermal. Excess works too.
Hopefully the loop will be able to be used for subsequent geothermal installations, so that's even better.
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