Holy Power Costs, batman!

98turbodsl,
I too use water to air geothermal in Michigan (DTE).
My compressor just fried so geo is a painful concept right now ($5K painful parts only for new geo unit)
Just ordered it's replacement. The original unit is 15 yrs old and it fried it's second compressor.

My bill for Jan is 5439 kwht for $356 for "time of use" (geo plus H2O) I am not seeing a pricing increase for time of use, but I am looking at the online bill which isn't quite as detailed as the paper bill.

The residential electric is 1248 kwht for $159 also for Jan.

beezlerob, yes, geo is much cheaper over energy cost compared to propane or natural gas. Heck, I just did the calc....even the secondary electric heat is cheaper than propane now. My current secondary is propane and the new geo unit I just ordered will have electric. The propane will be a "third stage" really meant for power outage when the house is running on generator. I am heating on propane right now, and didn't hesitate to order the new geo unit, even though it's painful shortterm.

My propane (just paid those fargin bastegis yesterday) was $2.79 / gallon, and when I complained, they didn't hesitate to provide a "$75 rebate" coupon that brought the effective price down to $2.49 or so. That is still $0.50 overpriced if I owned my own tank and could shop them. At these prices....Geo is much cheaper.
 
Well, our primary is an air-exchange heat pump, and our secondary heat is a wood fireplace.

I guess what I'm wondering is....isn't geothermal better heat? I mean better than my air exchange. The reason I ask is because I was monitoring the air duct temp right above the fan, and when it's 40 deg outside, that air temp gets up to around 100deg...good heating! But when it was down in the single digits in Feb, the best the heat pump could do was something like 78 deg. So, by the time that air went back out the ducting and into the rooms, it was doing pretty much nothing, so the heat pump ran a long time...and of course, several defrost cycles just made it colder inside, enough so the electrical backup elements came on.

So I'm just wondering if geothermal puts out GOOD heat, all year round. I'm just imagining in my head that it's as good year-round as the air-exchange heat pump is when it's 40+ outside.
 
DavidL said:
My bill for Jan is 5439 kwht for $356 for "time of use" (geo plus H2O) I am not seeing a pricing increase for time of use, but I am looking at the online bill which isn't quite as detailed as the paper bill.

The residential electric is 1248 kwht for $159 also for Jan.
Click to expand...

holy crap. My bill for 1000Kwh is something like $300 or more.

Thank god CA decided against more nucular (sic) power.
 
IVB said:
DavidL said:
My bill for Jan is 5439 kwht for $356 for "time of use" (geo plus H2O) I am not seeing a pricing increase for time of use, but I am looking at the online bill which isn't quite as detailed as the paper bill.

The residential electric is 1248 kwht for $159 also for Jan.
Click to expand...

holy crap. My bill for 1000Kwh is something like $300 or more.

Thank god CA decided against more nucular (sic) power.
Click to expand...

Well, soon you'll have all these twirly things on the coast pumping juice into all of california's import car batteries that act as a reserve for your SageTV PC server and extenders.
 
beelzerob said:
Well, our primary is an air-exchange heat pump, and our secondary heat is a wood fireplace.

I guess what I'm wondering is....isn't geothermal better heat? I mean better than my air exchange. The reason I ask is because I was monitoring the air duct temp right above the fan, and when it's 40 deg outside, that air temp gets up to around 100deg...good heating! But when it was down in the single digits in Feb, the best the heat pump could do was something like 78 deg. So, by the time that air went back out the ducting and into the rooms, it was doing pretty much nothing, so the heat pump ran a long time...and of course, several defrost cycles just made it colder inside, enough so the electrical backup elements came on.

So I'm just wondering if geothermal puts out GOOD heat, all year round. I'm just imagining in my head that it's as good year-round as the air-exchange heat pump is when it's 40+ outside.
Click to expand...


Is your's an air to air heat exchanger that has a heat pump in the middle? Is the heat pump air to air or pulling the heat from water?

I believe a water source is more efficient due to the higher thermal transfer rate. My water to air geo never varies much in output temp. The geo runs most all the time, continuously adding a bit of heat to keep the home moderate. The secondary heat (mine currently is propane, but switching next week to electric) chimes in when the geo set point isn't able to be achieved (not enough btus). In my new system, I'll have my current propane secondary as a third (emergency) stage that is really intended for power outages.
 
DavidL - I guess you have some sort of generator for the house? I assume the unit still requires power to run the circulating fan, etc even if it is using propane.

We have natural gas as our primary heat source, but no generator. So we are still SOL in a power outage. Luckily they don't happen very often and therefore a generator really hasn't been justified.
 
We have a generator subpanel and portable generator, but the heat isn't wired into it. That's what the fireplace is for, mainly. It adds heat during the colder days of winter, but it was mostly thought of as our most emergency-type heat.

I have an air to air exchanger, I guess you'd call it. There's the big unit outside that gets the heat from the air, and then it brings it into the inside unit where the fan is.

Not varying during winter is part of the reason I'd like geothermal, because like I said...when it's down in the single digits downstairs, I see upper 70's for duct temps, but when it's in the 40's, it's closer to 100.

If the geothermal is always exchanging with water that's around ground temperature (around 50 deg or so) then I guess I don't understand why it'd have to run all the time, or wouldn't even be able to keep the house warm. Isn't that more than enough heat coming out? If my air exchange heat pump can produce 100 deg of heat from 40 deg air, I'd think a ground exchange would do even better with 50 deg water.
 
I read most of this thread a few days ago, and had previously read quite a bit of the same topic on the AVSForum as well.

This had me pull out my power bills. I did an average over the past 11 months - its all ive got since we moved .. we've averaged 1191-kWh. Im not sure if its because I have a 1500sq ft home, and some of you guys are in mini-mansions, or that because my home was actually built a year ago and has some better insulation, etc. but I'd really like to know where you use more than 1500kWh.

I honestly think a LOT of mine is incurred from the 2 Standard ATX sized PCs that I leave running 24/7. I feel that at $0.10 / kWh here in sunny FL is cheap enough right now for me to continue burning up the resources to leave them running - im too impatient to have to wait for the 2-5 minute boot time and initial startup applications, etc. If the power was more here, id probably be more patient with waiting. :)
 
sic0048 said:
DavidL - I guess you have some sort of generator for the house? I assume the unit still requires power to run the circulating fan, etc even if it is using propane.

We have natural gas as our primary heat source, but no generator. So we are still SOL in a power outage. Luckily they don't happen very often and therefore a generator really hasn't been justified.
Click to expand...


Yes. I have a 15KV Generac air cooled running on propane (more power than same generator on natural gas - which would be 13kv) with a Generac automatic transfer switch.

I have the emergency heat (120K btu propane high efficiency) furnace plugged into the transfer switch. The 24v AC stuff (including the thermostat), the circulation fan, are on the generator's transfer switch...so...no problem with heat when on extended power outage.

The Geothermal primary heat and electric secondary is on the low cost meter, that isn't switched by the transfer switch (since the generator can't provide enough juice for the 5ton compressor anyway).

The water heater, stove (propane), microwave, fresh water well pump, my server room (each PC has a UPS), are some of the things on the transfer switch. Once automatically transferred, I can elect to manually switch over all other circuits to the generator (if power outage is expected to go long).
 
drvnbysound said:
I read most of this thread a few days ago, and had previously read quite a bit of the same topic on the AVSForum as well.

This had me pull out my power bills. I did an average over the past 11 months - its all ive got since we moved .. we've averaged 1191-kWh. Im not sure if its because I have a 1500sq ft home, and some of you guys are in mini-mansions, or that because my home was actually built a year ago and has some better insulation, etc. but I'd really like to know where you use more than 1500kWh.

I honestly think a LOT of mine is incurred from the 2 Standard ATX sized PCs that I leave running 24/7. I feel that at $0.10 / kWh here in sunny FL is cheap enough right now for me to continue burning up the resources to leave them running - im too impatient to have to wait for the 2-5 minute boot time and initial startup applications, etc. If the power was more here, id probably be more patient with waiting. :)
Click to expand...

The electric bill I mentioned for my home...the majority is for the geothermal heating / cooling system. In Michigan, this is on a substantially discounted power meter. One can have the domestic hot water, any circulation fans, any control system (my HA system), legally on this cheap meter. One can also plug an electric car into this meter.

I would go broke trying to heat this home strictly on propane. The home has most all energy efficiency construction techniques and materials (foam basement walls / underfloor, Tyvek wrap, foam and cellulose insulation etc), but has lots of window area that is not energy efficient (even with the argon filled windows). My 5 ton geothermal should really be 6 ton to keep up with the energy loss. Unfortunately, that jumps up to commercial scaled equipment and much more initial investment.


The residential electric is a second "expensive" meter (not expensive relative to California...). This is for all other electric needs. I just flipped the most used 65watt recessed lights to Compact flourescent that are supposedly dimmable, but not the case with Insteon dimmers so far. Jury is still out in my home on whether they stay or get relocated to less used areas.
 
drvnbysound said:
This had me pull out my power bills. I did an average over the past 11 months - its all ive got since we moved .. we've averaged 1191-kWh. Im not sure if its because I have a 1500sq ft home, and some of you guys are in mini-mansions, or that because my home was actually built a year ago and has some better insulation, etc. but I'd really like to know where you use more than 1500kWh.
Click to expand...

I've been tracking mine for a few months now. Average usage is about 1200kWh over the last year in a 1900sq ft home. Right now it's a bit higher. with the average close to 50kWh per day. This is in Northern CA. If nothing is extra is running, the house is using about .8kW per hour. So of that 50kWh, half of it is heat pump, water heater, dishwasher, washer/dryer, and oven. The heat pump accounts for a majority of it. This is when the lows are in the mid 30's. Just this morning the heat pump and hot water heater probably used 9 to 10kWh.
 
"I'd be interested to hear how this works?

Brian "

In the transfer switch, there is a 100amp double pole breaker that backfeeds another pair of breakers in the main power panel. I can manually turn off the utility mains on all panels (completely independent of a backfeed situation), and then turn on both double pole breakers. This then transfers the power from the transfer switch (fed by the now running generator) to the main panel. I can then manually select / deselect circuit branches to power up by switching breakers on the main panel. My main panel also goes out to several subpanels like for the theater room, the boat house, a second house wing, etc. This is no different than how people use a generator that don't have an automatic transfer switch.

The key is to make sure you hit the switches in the proper sequence. Even though I "know" how to do it...I still documented it (stuck on the transfer switch panel) in case I go brain dead during a power outage. I don't want to shock anyone working on the utility pole, and also don't want to fry any of my electronics.

If my transfer switch had lots more breaker spots (It has something like 16), then I wouldn't need to do the "secondary" manual transfer step. This was a cost / benefit decision. I must have a close to a hundred breakers in the whole house as the home was "home run wired" for a centralized lighting control system (like a Vantage or Litetouch) that I never installed.
 
beelzerob said:
We have a generator subpanel and portable generator, but the heat isn't wired into it. That's what the fireplace is for, mainly. It adds heat during the colder days of winter, but it was mostly thought of as our most emergency-type heat.

I have an air to air exchanger, I guess you'd call it. There's the big unit outside that gets the heat from the air, and then it brings it into the inside unit where the fan is.

Not varying during winter is part of the reason I'd like geothermal, because like I said...when it's down in the single digits downstairs, I see upper 70's for duct temps, but when it's in the 40's, it's closer to 100.

If the geothermal is always exchanging with water that's around ground temperature (around 50 deg or so) then I guess I don't understand why it'd have to run all the time, or wouldn't even be able to keep the house warm. Isn't that more than enough heat coming out? If my air exchange heat pump can produce 100 deg of heat from 40 deg air, I'd think a ground exchange would do even better with 50 deg water.
Click to expand...

Depending on if you have a horizontal ground loop or open loop system, it's a misconception that the ground can replenish the heat as quickly as you can pull it out.
When it was real cold last month, I put a thermocouple into the supply loop to see what the delta T was running, and even though our ground temps here run about 50F at 6' depth, my water supply temps were about 34F or so.
That's typical for end of season in my opinion. My feeling is that you probably lose a bit of capacity as the winter goes on. I'll work on improving the tightness of my house over this year and hopefully keep up a bit better next year.
Meanwhile, I'm using propane to supplement.
 
Ya, I knew that the water in the loop would get "colder" over the winter, as the heat doesn't flow that fast through the ground to the loops. Low 30's doesn't seem so bad, I was hearing that temps get into the single digits towards end of winter in horizontal loop systems here.

Is yours horizontal or vertical loops? I'd think vertical would be better at replenishing the heat, wouldn't it?

I think we're still a couple years out from being able to seriously consider geothermal...at least in that time, I should be able to log and note my heating/cooling costs separately, so that will give me some better idea of the payoff time.
 
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