Went to POCO Net Metering Seminar

[MTY]

I had enough info from reading to understand what was presented from a technical perspective. The economics were disappointing to say the least.

They have had a demo 1KW set up for 10 years. The average payback per year was $122 on this system. We pay .091 per kwh. Local costs are approximately $15K for a 5KW installation, and for every 5KW you get approximately $620 back per year. They also said that due to degredation of the system one could expect a 50% reduction in output at the 10 year mark.

They allow accumulation of credits for one year and they also buy back at the .091 rate. However, they calculate on a calendar year and there is little production for the first 6 months. So for half the year you pay almost your entire bill or you build a large enough system that at the end of December you lose a large amount of credit.

Their general recommendation was to build a system that would cover 50% of your yearly usage if you did not want to give back credits at the end of the year. At the 10 year mark you would then be producing 25% of you yearly usage and would need to replace the panels.

The recomendation in my particular case was conservation. Since it is new construction, insulate the heck out of it, and put in geothermal heat pump system.

For the well, the recommendation was to put a smaller ac pump in the well, run it for longer periods at a time to fill the cistern and then have a long down time before there is a requirement for more pumping.

The basic premise was that I would not live long enough to benefit financially from putting in solar unless the rates rose drastically and the cost of a system dropped significantly. If I got satisfaction from using solar, I would have to balance that against cost.

 

[peakbagger]

There are some suspicious numbers you are quoting which implies bias on the presenter. First thing is the system cost.Three dollars a watt is actually high these days given the collapse in panel pricing. Generally that is pre federal and state rebate (if there is one). The federal rebate is 30% of total installed cost scheduled to drop to 28% next year . Lets assume there is no state or local rebate so the federal rebate is $4,500 off the top. That is a tax credit not a deduction so assuming you pay income taxes, its a one for one reduction. thus the 5K system at the inflated $3 a watt cost is $10,500.A DIY install can easily go in for $2 a watt and a competitive installer who buys in bulk can do it in the $2.50 per watt range.

Next issue is the panel degradation is way too conservative, It may apply to some early amorphous panels but mono and poly panels have proved to have lower long term degradation then what manufacturers will warranty. There is an initial drop when the panels are installed in the first few months but that is generally accounted for in the delivered panel rating (the manufacturer includes the initial burn in. Many new PV owners notice the initial extra output and if they are watching closely notice that initial drop off but soon realize that the degradation is lower iin the long run. Once the burn in has occurred a conservative number is 1% per year, so in 10 years a conservative loss is 90, its actually less for most installations, many 20 year old panels are still in the 90% of nameplate.

The percent to offset your load is entirely dependent on you load over the course of the year, if there is reset date and when it is and if the utility pays you for the reset. These are all moving targets so you need to estimate your loads and see when your loads are occuring on your calendar relative to the reset date. I have more panels than my electrical use and use to surplus to run my minisplit for shoulder season heating as I do not have reset date.

I do agree with the suggestion that saving energy is the best investment although at some point there is overkill where the extra money spent exceeds the long term reduction in energy costs. That is going to vary with your local climate. There is concept called the Pretty Good House for New England that takes into account economic payback as well as energy savings. There is also the Passivhaus standards that are generally regarded as overkill. Ideally there should be energy and cost modeling for each specific house design in each specific area but few house builders are going to go to that trouble. The trick is the best bang for the buck is sealing out infiltration of outdoor air. Many builders do poorly with this and introduce permanent leaks due to poor building practices caused by speed. On a custom home the owner may be able to negotiate a infiltration guarantee but generally by the time the house is built its too late. Many homeowners having a house built chase the builders after hours caulking and sealing cracks. There is also a technique where the stud bays are sprayed with spray foam first to seal any air leaks and then regualar fiberglass batts are inserted making sure that the batts are a bit overlength to compensate for settling. Thermal bridging is also a secondary concern. Many builders use standard framing techniques and put in way too much wood. An example is window headers. The average builder uses a standard header design suitable for a load bearing wall on non load bearing walls and generally use corner framing that has inherent thermal bridging. The pretty good house folks and others have modified framing techniques that substantially reduce bridging, I also am an advocate of putting in insulation on the basement walls and under the basement floor after a full perimeter drainage is installed as the conductivity of wet soil is far more than dry soil.

The recommendation for geothermal is very site specific, if you are in easy to drill soils or have access to reservoir like a pond it may make sense but generally the initial cost is very high. Most systems are designed to tie into forced air systems and unless the ducts are well sealed and insulated and installed inside the insulated envelope, its a costly approach. Most super insulated homes use hydronic heat and air source minisplits for cooling. If the house was designed correctly with appropriate shading, thermal mass and window glazing the cooling load is lower.

The advice for water pumps is also curious and dated. The current approach is variable speed drive pumps that do not have startup surges, they only run when needed to match the demand. If you are in low yield well area, the alternative is to install a storage tank in the basement fed by small pump from the well and then have a variable speed drive demand pump off the tank. Its also a nice fit if you have radon issues as you need to pump in the basement to re-pressurize the water after it goes through the radon scrubber

If you accurately conveyed what was being advocated at the seminar it sound suspiciously like what would be offered by a biased source like a power utility that doesn't want solar on their system and is working on dated information. Be careful where you get you data from and see what biases are built into their presentation.

You didnt mention if there is SREC market in your region, that also would reduce the payback of the system.

The last thing is the long term intangibles we cant predict. Its highly likely that power costs are going to increase tied to global warming mitigation. The current administration in Washington may have delayed things in the short term but Carbon taxes of some sort either direct or indirect is going to shift the cost of power up in the long term.

 

[sloeffle]

The recomendation in my particular case was conservation. Since it is new construction, insulate the heck out of it, and put in geothermal heat pump system.

I'd pass on the geothermal system since you are in a heating based climate. We have one, the heat is okay. IMHO - geothermal shines when we are running the air conditioning. As @peakbagger said, I'd look into hydronic heating with some mini splits for AC. Some of the new mini-splits actually have a higher COP than our geo unit.

 

[maple1]

Geothermal didn't come close to penciling out for here. Cold climate mini-splits are IMO a much better choice. If I was building new again, I would do that plus a wood stove to supplement or for power outage situations. But having said that I would also re-assess geothermal - things may have changed on that since I did my penciling, and starting from a clean sheet on a house build might help that situation.

 

[MTY]

There is a lot to digest. The house we live in is not well insulated, and the heat pump does well until the temp gets in the 20's. I was under the impression that a geothermal heat pump was more efficient, and that 4 foot and below had fairly stable earth temps.

The trenches are basically free as I have a mini ex and will be digging in water and power lines and was told I could use the same trench. A rough estimate was 200' of trench for each ton of heat pump, so I would need 800' of trench. This was from a contractor. His opinion, and he has no connection with the poco, was that the geothermal heat pump had one strike against it and that was the cost of trenching.

I was also under the impression that hydronic heat had to be run constantly as the warm up time for the concrete is significant.

The basement floor has not been poured yet, but I did purchase 2" insulation for the entire floor. I have been debating throwing pex loops in as it is a now or never propositon. The part of the house with a crawl space is insulated with 2" foam on the outer walls. All duct work will be within the insulated envelope. I put a significant drainage system around the house, put in additional solid pipe that exits the hillside 30' away from the foundaton for down spouts, and then threw an extra tile in for good measure.

There are 7' eves on most of the house. They do a good job of keeping the sun off the windows.

The structure will be sprayed with 1" of closed cell prior to insulating.

The poco will not pay for credits remaining at the end of December, and I could not use them for heating in January through April as they expire prior to the beginning of the year.

Before I give up on the solar idea, I will get bids in an effort to better understand the costs.

It is a 30gpm well, but I have to raise the water 500'.

 

[peakbagger]

Up in NH they usually drill bore holes that are good for 300 feet per ton of heat (12000 btus). The trench installs do not have great rep in my area as they can deplete the heat in the ground around the tubing, the ground temp is low to begin with and as the winter goes on the loop temps slowly degrades.

With that depth of well it makes sense to go with positive displacement pump pumping to storage tank in the basement. PD pumps are far more efficient than multistage centrifugal pumps. The grundfos pumps are popular as they ac/dc systems so they can be run with solar or house current. (broken link removed)

 

[maple1]

Those around here I know who put Geo in have told me their power bills ended up being more than they expected. I don't know what their bills or expectations were. But fairly competent pumps are needed, running 24/7, to keep the water flowing through the ground. Plus the inside units. These were trench installs - I don't know how the past winter was for them, but the frost got deeper this year than it ever has before. Reports of 6' deep were common.

Add in the fact that for the cost of one Geo unit I could likely have 7 or 8 mini-splits installed, that's not good for the Geo either.

 

[MTY]

I have only seen one mini split in a home, and it was a big bulbous thing mounted on the wall. So, that is pretty much my impression of them, and the female unit would be difficult to convince that would be the way to go.

Anyone I have talked to around here as spoken about trenches with no mention of bore holes. Frost depth is 30". I'd be happy to walk away from the geo idea if there was an eye appealing alternative.

It is the Grundfos pump that I was looking at when I was thinking solar for the well. It will run on ac or dc, so if there were cloudy days beyond what my storage capacity was I could hook up ac to it. The storage tank is 2100 gallons and will sit 50' above the house. The gravel truck sank while trying to place rock in the bottom of the pits on last Thursday. I will have to wait for the ground to dry a little more before I bring the cistern in. I have a second cistern of the same capacity that is gravity fed by the spring that handles all outside watering chores.

My original plan was to build an energy efficient house, run the pump for the well off solar as much as possible, primarily heat with wood and have resisitance heat for back up if we had to leave in winter. My big concern is being 90 and still being able to stuff wood in the stove, so I am trying to come up with an alternative that will be vialble 20 some years down the road. I'd rather live remote and be ate by a coyote at 90 than rot in a nursing home.

 

[maple1]

There are different types of inside units for mini splits. I'd suggest checking them out especially in a new construction scenario. A ceiling cassette might be a really good solution. We put two in back in November. One is up high on a wall, the other is a floor mount unit fastened to the wall right above a baseboard housing. We put those in for a lot of the same reasons you are assessing things for.

 

[sloeffle]

The trenches are basically free as I have a mini ex and will be digging in water and power lines and was told I could use the same trench. A rough estimate was 200' of trench for each ton of heat pump, so I would need 800' of trench. This was from a contractor. His opinion, and he has no connection with the poco, was that the geothermal heat pump had one strike against it and that was the cost of trenching.

When we had our geothermal system installed I talked to three different installers about the amount of loop they recommend per ton of furnace. One told me 200 ft per ton, another told me 150 ft of slinky loop per ton, and last but not least another told me 600 ft of pipe per ton. Luckily I had a hay field available to put the trench in. As the others have eluded too, when you start boring holes the price goes up significantly.

We chose the installer who put in 600 ft of pipe per ton because I talked to a couple folks who put in 150 - 200ft per ton and they weren't very happy by the end of the heating season with their system because the auxiliary heat was kicking in all of the time to keep up. My guess is that the loop temps are so cold that the unit can no longer efficiently extract any heat from the ground. I'd rather pay up front a little ( pipe and digging are cheap IMHO ) vs paying $2.50 per hour to run my aux heat.

Our system is a four ton Waterfurnace Envision ( 5 series now ) and we have 2,400 ft of pipe in the ground. I had two trenches dug six feet deep that are 300 feet long. The pipe goes out of the manifold at six feet and then returns back to the manifold at four feet of depth. When they were putting the pipe into the trench they used a metal clip to hold the pipe against the wall of the trench at four feet. The guy operating the track hoe also has to be on his game so he didn't collapse the pipe when back filling. The loops were pressure tested because and after back filling too.

Good luck with your decision. If money is not an object I'd have a wood boiler with heated floors and couple mini splits for A/C. I'd still recommend a second source of heat in case your power goes out. If you plan to run the geo off of a generator you will need at least a 10kW generator if you get the soft start kit installed on your unit. It takes the LRA of the compressor down from 100 AMPS to around 35 AMPS in my case.

 

[peakbagger]

The other technology that the hydronics guru, John Seigenthaler is pushing are air to water units. These have an outdoor unit like a regular minisplit but send warm antifreeze indoors that then can be run to fan convectors that sort of look and work like minisplit or in your case radiant. The nice part with these units is there is no need to have a tech come and charge the lines. They are used elsewhere in the world but just coming to the US. They fit perfectly with small wood boiler. and storage. They also can be used for cooling but fan convectors are needed for most installations as radiant cooling is very risky due to potential condensation issues.

BTW radiant is best as set it an forget it. It responds very slowly to changes in temperature set point so you set the thermostat at one setting and leave it there.

 

[SpaceBus]

The other technology that the hydronics guru, John Seigenthaler is pushing are air to water units. These have an outdoor unit like a regular minisplit but send warm antifreeze indoors that then can be run to fan convectors that sort of look and work like minisplit or in your case radiant. The nice part with these units is there is no need to have a tech come and charge the lines. They are used elsewhere in the world but just coming to the US. They fit perfectly with small wood boiler. and storage. They also can be used for cooling but fan convectors are needed for most installations as radiant cooling is very risky due to potential condensation issues.

BTW radiant is best as set it an forget it. It responds very slowly to changes in temperature set point so you set the thermostat at one setting and leave it there.

If you already have a wood stove (radiant in my case) that can deliver my entire heat load, would one of the air to water units, such that Tom sells, be capable of providing AC and heat (convective) for a small house? The cost of installation is very attractive since the cost to install a normal mini split is horrendous and often more than the unit.

 

[peakbagger]

If you already have a wood stove (radiant in my case) that can deliver my entire heat load, would one of the air to water units, such that Tom sells, be capable of providing AC and heat (convective) for a small house? The cost of installation is very attractive since the cost to install a normal mini split is horrendous and often more than the unit.

Its a good shoulder season unit. I am not sure of the installation savings as I think the unit that Tom imports is more expensive up front. I took a look to check pricing on the AST website and couldnt locate the listing. As long as the convector is set up with pan and drain it should work as well for cooling as a mini split.

 

[SpaceBus]

Its a good shoulder season unit. I am not sure of the installation savings as I think the unit that Tom imports is more expensive up front. I took a look to check pricing on the AST website and couldnt locate the listing. As long as the convector is set up with pan and drain it should work as well for cooling as a mini split.

Perhaps the economics will change.

 

[MTY]

Lots of good info.

Part of the problem with building is deciding whether this is going to be the place or whether one will be moving on in a few years. That in part dictates how overboard one goes in building. It does not make sense to sink a lot into a place knowing you will not recoup it, and that future owners most likely not appreciate it.

That said, I am planning on kicking off at the new place. In my late sixties I know that I will not remain spry forever. With that in mind, I am trying to set the place up so that when I can no longer drag wood to the stove, I can crawl over and turn on the heat. I do not want to be retro fitting something in ten to twenty years. So, thanks again for helping me work through this.

Tomorrow the first of the heat guys is supposed to show up and give me a bid on geothermal. The lifespan of the system has me as interested as much as anything else. No decisions have been made yet.

 

[peakbagger]

I would not bet on long life as many of the refrigerants of the past are being phased out and replaced with replacements that seem to required higher and higher pressures which usually increase wear by as the pressure goes up. Most HVAC is 10 to 20 year life with annual maintenance. The high end geothermal systems installed in my area are normally sold with long term service plans which assume major equipment replacement into the pricing.

 

[Highbeam]

Its a good shoulder season unit. I am not sure of the installation savings as I think the unit that Tom imports is more expensive up front. I took a look to check pricing on the AST website and couldnt locate the listing. As long as the convector is set up with pan and drain it should work as well for cooling as a mini split.

Earlier this year tom’s 30k btu air/water heat pump was 2500$. Including shipping as I recall. These things just set outside, you run power to it a control cable, then supply and return lines. 30k btu is 2.5 tons which should be plenty for a decently built and sized home. You can also make domestic hot water.

Tom and his small company seem to be real good folks but this equipment is not made by any brand name company. I’d like to see the big players adopt this basic technology.

 

[begreen]

Too bad we don't have access to Asian options. Midea is the largest major appliance mfg. in the world, but their air to water HP is not sold here.

 

[Highbeam]

Too bad we don't have access to Asian options. Midea is the largest major appliance mfg. in the world, but their air to water HP is not sold here.

Is this one of those deals where a good product threatens the economic well being of some powerful american companies so it is “hidden”?

 

[peakbagger]

It takes a lot to introduce new tech to the market. There has to be US product certification, a distributor, installers, and a warranty channel.

 

[begreen]

It wouldn't surprise me if one of the US majors worked out a deal to resell Midea products under their own label.