Geothermal related to cooling in Michigan.

[homedad]

Thanks for all of the opinions. With my limited knowledge of geothermal I assumed that the 55 degree ground temperature would have been a huge advantage but I never considered the need for a compressor. It's a lot of empty land and I'm capable of installing trench loops but the electricity is the deal breaker. I only use AC for sleeping so I suppose I'm better off sleeping in a small guestroom with a window unit.

 

[hube2]

I only use AC for sleeping so I suppose I'm better off sleeping in a small guestroom with a window unit.

I installed air sourced heat pump for the reason of the eliminating the noise from window units. Air sourced will not be as efficient as ground but will cost a whole lot less. I did not install them to save money on AC.

I am however spending significantly less overall when I factor in heating costs. Still, it will take me nearly 20 years (if I live that long) to get my money out of them. But air sourced pumps only have a life expectancy of 10 to 15 years which basically means that I will never see a return on investment unless the cost of fuel oil triples or more in price. And I still need the oil fired furnace for the really cold days below the range of the pumps.

But it did not matter, I could not take the noise from the window units any longer. The heat pump is silent, you don't even know it's running.

 

[dodge man]

Think of geothermal like a regular ac unit but you go outside and spray the hot coils with water. It’s a little more complicated than that but that’s the general idea. Mine uses a little less than 2000 watts when it’s running normally on stage 1.

 

[KennyG]

If you only need the heat or A/C in limited areas and want to minimize the noise, look into mini-splits. They are not that expensive, you can do your own install and they are efficient. The A/C will be very efficient in Michigan if you can install the outside unit in a shaded area.

 

[deezler]

Thats BS. I've worked up there in 100 degree weather. However, I love it there and most of the time it is nice.

Lol ok bud. Much of the UP hasn't been over 100 degrees in decades. Here's data from Marquette, for example. Most years top out in the low 90s, and even those kind of heat waves typically only last a few days at most. Plenty of summer days that don't even hit 75. Depends on proximity to the lake shores, I suppose.

Highest Temperatures in Marquette by Year

www.extremeweatherwatch.com

 

[deezler]

The short answer is yes, geothermal is slightly more efficient, and should have slightly lower bills for central Michigan.

The longer answer geothermal will not lower your bill by much, and may not lower the cost at all in your lifetime.
Two factors are at play;
1) geothermal systems cost much more to install, either because of the wells, or the trenches to install pipes. They work best when the groundwater level is close to the surface and the pipes can be set in wet soil from the service. They also have to pump water around the loops, or up and down the wells for a standing water friction loss.
2) Air cooled heat pumps used not to function well in extreme cold, but that is no longer the case. Advances in heat pump design have enabled air cooled heat pumps that function in very cold -5F to -20F.

However, for both types, you will be best served by designing a home with super insulation. E.g. 12-16" walls, with offset studs or densified fiberglass outside of the studs, triple pane windows, air heat exchanger, R60 in the attic, double door entryways, and skipping the Viking gas range with its monster exhaust fan.

Peter

Dang, Peter nailed it on the first response! Should have closed the thread right after this post.

I would say that yes, geo-thermal will still be more efficient in mid michigan (especially with wet soils as others have noted) BUT, the install expense will take a lifetime to pay back.

Even with a gradually warming climate, mid-michigan has few days where A/C is truly warranted (10-15 max). Design your home with the climate in mind, and you barely need it (roof overhangs to prevent sunlight entering in summer, thick insulation everywhere, earth-berm the north wall of your house, etc). Overnight humidity in mid-michigan is rarely bad enough to prevent you from using free a/c all night long, then close the house up in the morning and you can hold in the 70s all day. But the beauty of starting with a well-designed and efficient home in the first place, is that one little mini-split heat pump system ($2500 DIY install) can easily hold you in the mid 70s with minimal electricity consumption. In our house in Southern Michigan it takes a few days of heat wave before we need to turn ours on, and then we don't feel guilty about setting it to 74°F cooling, because it sips electricity given the house design. Maybe 50 cents/day.

But the best part about mid-michigan is that usually the weather/air arriving to your location has passed over a great-lake and gotten free air-conditioning on the way! (which is also why its pretty cloudy all winter long).

 

[ponytug]

Dang, Peter nailed it on the first response! Should have closed the thread right after this post.

I would say that yes, geo-thermal will still be more efficient in mid michigan (especially with wet soils as others have noted) BUT, the install expense will take a lifetime to pay back.

Even with a gradually warming climate, mid-michigan has few days where A/C is truly warranted (10-15 max). Design your home with the climate in mind, and you barely need it (roof overhangs to prevent sunlight entering in summer, thick insulation everywhere, earth-berm the north wall of your house, etc). Overnight humidity in mid-michigan is rarely bad enough to prevent you from using free a/c all night long, then close the house up in the morning and you can hold in the 70s all day. But the beauty of starting with a well-designed and efficient home in the first place, is that one little mini-split heat pump system ($2500 DIY install) can easily hold you in the mid 70s with minimal electricity consumption. In our house in Southern Michigan it takes a few days of heat wave before we need to turn ours on, and then we don't feel guilty about setting it to 74°F cooling, because it sips electricity given the house design. Maybe 50 cents/day.

But the best part about mid-michigan is that usually the weather/air arriving to your location has passed over a great-lake and gotten free air-conditioning on the way! (which is also why its pretty cloudy all winter long).

Thanks for the compliment!

It sounds like you have a really well designed home. Perhaps there ought to be another thread on efficient and well designed homes in particular.

The climate in mid Michigan is pretty sweet, although I admit that I find those winters pretty grey.

On the bright side, there's a bunch of great people there, too!

All the best,

Peter

 

[not2old]

Just to give you an idea on the efficiency of geothermal, my blower motor quit a couple of weeks ago and I had to heat the house with electric space heaters. I calculated the electricity usage to be about $40.00 per day for a week and that would have cost me about $1200.00 had I needed it that long. My usual electricity bill for a month this time of year is about $300.00 for everything electrical we use. New motor was over $1600.00 with freight from Texas, plus labour.

 

[mikester]

Like others have said a GSHP will cut your cooling costs by about half.

The real question is WHY you are spending $400/month on cooling costs. Do you leave all the windows and doors open and the A/C on full?

Here's an interesting quote for you "80% of a building's cost in it's lifetime is the day to day operation, NOT the construction cost".

Check out Passiv Haus

 

[Sigarms]

If you only need the heat or A/C in limited areas and want to minimize the noise, look into mini-splits. They are not that expensive, you can do your own install and they are efficient. The A/C will be very efficient in Michigan if you can install the outside unit in a shaded area.

With mini splits (ductless which everyone thinks about or ducted), generally the cost is associated with the actual performance for capacity available for both cooling AND heating.

I can buy a 1.5k mini split or 3k mini split from the same manufacturer at the exact same capacity size. Reason for the price difference? Generally the amount of heat that system can provide in colder climates.

I've dabbled with Geo (perhaps 10 jobs) in NC and that's it. It is expensive, but if you can provide your own labor for the digging and piping, it's something I would look at because Geo equipment isn't that much more than "higher end" HVAC equipment.

That said, generally what people forget about is the ductwork. Sheet metal, insulation and general duct layout (manual D) attributes a good percentage of the overal price as well.

With ductless mini splits, no duct is needed which is great (saves time and money of course). That said, I'm a big propronent of ductless mini splits for single up to 3 zone applications, but for using it for the whole home (where depending on the layout, more than 3 zones are needed), I'm not a big proponent due to potential future service issues as well as swing in temperature zones within the house given it's location and layout.

If the OP will be using wood for back up heat, I'd give serious consideration of the layout of the home to maximize that fuel source.

 

[Sigarms]

My current home electric bill is closing in on $400 per month in the cooling season.

I've got to ask, what is the square footage of the home and what kind of condition is the ductwork in? I'm in NC, have 3 HVAC systems, and even in hot NC summers, my bill is about the same as yours, which I would expect in my own home given it's size. But in Michigan?

Next question is what are you paying per KW? (funny, our electric company is playing a shell game now with various "peak hours" of operation where they charge you more). My wife puts a sign on the washing machine and dryer when I can't operate them because it's "peak" time where we pay more per KW.

 

[homedad]

My home including all conditiond space is about 5200 sf. The kWh they charge is very difficult to actually measure because of their fee structure. The highest peak charge is .09 per kWh. A website states that I pay about .14 per KWh. If I divide my bill by the kWh used it’s more like .20 per kWh. I had my son looking at my bill and he concluded that my fees are about 40% of my bill. I feel like my bill will always be at least $100 per month even if I never turned on the main breaker.

 

[deezler]

My home including all conditiond space is about 5200 sf. The kWh they charge is very difficult to actually measure because of their fee structure. The highest peak charge is .09 per kWh. A website states that I pay about .14 per KWh. If I divide my bill by the kWh used it’s more like .20 per kWh. I had my son looking at my bill and he concluded that my fees are about 40% of my bill. I feel like my bill will always be at least $100 per month even if I never turned on the main breaker.

I'm sure you have Consumers for electric grid up there, right? We have DTE down in the southeast, but the billing games are similar, I believe.

The nominal grid connection fees if you consume zero kWhr is not that much, maybe $9/mo? At least for my DTE, which is how my bill looks all summer long because my 5.5kW solar array is covering all my consumption. Most of the line items on your bill are still calculated based off consumption during their respective time periods.

That's a big house... Probably not wise to cover it all with so many discrete mini split systems. Do you have funding readily available to consider a big investment in Geo?

 

[Sigarms]

That's a big house... Probably not wise to cover it all with so many discrete mini split systems. Do you have funding readily available to consider a big investment in Geo?

The issue is when you way mini split, do you mean ductless or ducted?

In the HVAC industry, these terms can get confusing since most manufacturers offer a inverter compressor HVAC system.

Another variable....

If you have a 5k sq ft house, depending on the way it was built with insulation, it could require a total of over 60,000 BTU/h of heating and cooling, OR it could require less than 24,000 BTU/h of heating and cooling.

My own home is 3,200 sqaure feet, and due to the window areas along with basement below grade, takes over 80,000 BTU/h for heating and cooling, BUT, the below grade basement and large window spaces on the 2nd and 3rd floor actually "compete" against each other for cooling and heating for the entire house (using 3 systems).

When you go with a single stage compressor HVAC system, doing gas AC, you may need 20-40K of heating with the gas furnace, but pretty much no AC, but by the time you add in ductwork, it makes no sense not to have the AC option for whatever reason.

The bigger issue people forget about with loads for larger homes is air flow meeting those heating and cooling requirements for various spaces using only 1 system.

A house that is 5k sq ft that requires 2 ton or less heating and cooling, the issue becomes meeting the air flow requirements and finding equipment with the proper blower speeds to hit those air flow requirements for the ductwork.

I also could be wrong, but I believe the OP is moving/building a smaller house.

We only have 3k sqare feet, and now that my wife and I are empty nesters, our next move/build will be definitely smaller LOL

 

[homedad]

I'm sure you have Consumers for electric grid up there, right? We have DTE down in the southeast, but the billing games are similar, I believe.

The nominal grid connection fees if you consume zero kWhr is not that much, maybe $9/mo? At least for my DTE, which is how my bill looks all summer long because my 5.5kW solar array is covering all my consumption. Most of the line items on your bill are still calculated based off consumption during their respective time periods.

That's a big house... Probably not wise to cover it all with so many discrete mini split systems. Do you have funding readily available to consider a big investment in Geo?

We're at the planning stage for the new property. The new home will most likely be around 1500 to 2000 square feet so much cheaper to cool and heat. I'm not even certain about the cost to install geothermal. After reading all of the opinions it appears that I'll just go with a traditional gas fired forced air system with either a minisplit or a window ac since I use a sound machine anyway. I had always planned to install a solar array with battery storage as well but this also sounds like a huge initial investment with minimal or no financial advantage in 30 years over grid tied electricity since the lifespan of the system is about 25 to 30 years. I also understand now that it's illegal to go completely "off-Grid" with electricity so now I'm not really certain if I can even predict what my electric bill would be. I'm assuming there's some sort of a punishment I'd have to pay for not using their electricity even though I have their wire going to my home. I guess this says more about me and my skepticism of the utilities.

 

[Sigarms]

After reading all of the opinions it appears that I'll just go with a traditional gas fired forced air system with either a minisplit or a window ac since I use a sound machine anyway

If you're on LP for the any heat, depending on what you're paying, I'd look to go a least dual fuel system (heat pump with a gas furnace for "back up heat").

Heat pump will run electric down to between 20F-40F outside air temp for heat, then bring on the gas furnace for supplementary heat when it gets colder.

If you feel fine using wood for an additional back up heat source, THAT will be your money saver IMO.

No watter what fuel source, unless you can provide it for free on your end, anyone supplying you the fuel source will sooner or later have you by the gonads.

 

[homedad]

The issue is when you way mini split, do you mean ductless or ducted?

In the HVAC industry, these terms can get confusing since most manufacturers offer a inverter compressor HVAC system.

Another variable....

If you have a 5k sq ft house, depending on the way it was built with insulation, it could require a total of over 60,000 BTU/h of heating and cooling, OR it could require less than 24,000 BTU/h of heating and cooling.

My own home is 3,200 sqaure feet, and due to the window areas along with basement below grade, takes over 80,000 BTU/h for heating and cooling, BUT, the below grade basement and large window spaces on the 2nd and 3rd floor actually "compete" against each other for cooling and heating for the entire house (using 3 systems).

When you go with a single stage compressor HVAC system, doing gas AC, you may need 20-40K of heating with the gas furnace, but pretty much no AC, but by the time you add in ductwork, it makes no sense not to have the AC option for whatever reason.

The bigger issue people forget about with loads for larger homes is air flow meeting those heating and cooling requirements for various spaces using only 1 system.

A house that is 5k sq ft that requires 2 ton or less heating and cooling, the issue becomes meeting the air flow requirements and finding equipment with the proper blower speeds to hit those air flow requirements for the ductwork.

I also could be wrong, but I believe the OP is moving/building a smaller house.

We only have 3k sqare feet, and now that my wife and I are empty nesters, our next move/build will be definitely smaller LOL

The current home is very well insulated but we also have a lot of big south facing windows which is great in the winter but we need to close big heavy curtains in the summer to keep the house cool. The AC is never turned on in the daytime and the house rarely goes above 74 degrees. It's completely about my need for comfort while sleeping. I like it cold or I can't sleep so the AC tends to run non stop all night on the upper floor bedroom zone. I think that the answer will truly be that minisplit or a window unit. I can get a window unit for $150 and it may not be as efficient as a minisplit but I'm guessing that the Minisplit is substantially more expensive upfront.

 

[Sigarms]

I'm assuming there's some sort of a punishment I'd have to pay for not using their electricity

Funny.

I was straight gas/AC on my 3 HVAC systems, decided to start changing them out to dual fuel (so I wouldn't have to use as much propane).

First year, cut my LP bill down by 30% by changing out one system.

Next year, letter from the LP company informing me that since I'm not using as much LP as in the past, my pricing per gallon is now going up.

Thought to myself I can't win...

 

[Sigarms]

The current home is very well insulated but we also have a lot of big south facing windows which is great in the winter but we need to close big heavy curtains in the summer to keep the house cool. The AC is never turned on in the daytime and the house rarely goes above 74 degrees. It's completely about my need for comfort while sleeping. I like it cold or I can't sleep so the AC tends to run non stop all night on the upper floor bedroom zone. I think that the answer will truly be that minisplit or a window unit. I can get a window unit for $150 and it may not be as efficient as a minisplit but I'm guessing that the Minisplit is substantially more expensive upfront.

If you're building a new home and it has new ductwork, and primary living space at night is a bedroom for you and your wife and the rest of the house it doesn't matter, zone the system for both the master bedroom and then the rest of the home.

Generally speaking, empty nesters, one zone HVAC system with single t-stat using LP for heat (AC or heat pump), it's a no brainer to put a ductless mini split in the master bedroom for additional heating and coolig (keep in mind, thermostat is not in the bedroom). This allows to lower heating temps in winter and raise AC temps in summer).

 

[deezler]

The current home is very well insulated but we also have a lot of big south facing windows which is great in the winter but we need to close big heavy curtains in the summer to keep the house cool. The AC is never turned on in the daytime and the house rarely goes above 74 degrees. It's completely about my need for comfort while sleeping. I like it cold or I can't sleep so the AC tends to run non stop all night on the upper floor bedroom zone. I think that the answer will truly be that minisplit or a window unit. I can get a window unit for $150 and it may not be as efficient as a minisplit but I'm guessing that the Minisplit is substantially more expensive upfront.

mini splits aren't too bad at all, and they are soooo much better than a window unit. My MrCool DIY 24k BTU system was only $2200, and cools my entire 1650 sq ft house just fine. Whisper quiet, too.