Right, so a PV system is essential to eliminating fossil fuels from ones "net energy use", but will be necessary for powering the grid until we build enough renewables. However, elimnating fossil fuels from ones' house is possible now, especially in a new superinsulated house, or a home renovated to net zero standards in a climate where it stays within the temperature range of the unit. More importantly is that eliminating toxic and flamable gasses and liquids from our home is possible.

Yes, move to a mild climate if you can.

As for "eliminating toxic and flammable gasses and liquids from our homes" look to the medicine cabinet first. The flammable gasses we have had covered for a couple of decades now, with sealed-combustion, direct-vent, gas-fired appliances. All this without the 70% loss associated with "the grid".

We have designed and installed mechanical systems for many "super-insulated" houses starting in the 1970's. I have an all-electric home on the trestle board now and lived in one nearly 20 years ago (converting it to a gas-fired condensing boiler saved me 35% on my fuel bills). If we could all build a new house wouldn't that be grand!

Some people knew how to build houses long before LEED or Passivhaus came along. Some of the new technology is more practical, some is a long way off. Most of our work is with gas-fired equipment but my own house is on an electric boiler, soon to be air-to-water heat pump, but most folks can't afford this technology yet. Even the air-to-air is beyond the average person's budget but the numbers are rising.

"Even the air-to-air is beyond the average person's budget but the numbers are rising."
Just installed air to air heat pumps in a 2900 Sf house for heating and cooling for about $10,000. If that's beyond most people's budget and less than gas or oil units in your area, your costs are far lower than mine.

that's in climate zone 6 in New England; probably not sigificantly milder than your area

In don't think so.

http://www.wunderground.com/news/subzero-temperatures-duluth-minneapolis-green-bay-chicago-20140225?pageno=3

You might have more luck trying to convince people that burning fossil fuels to make a more refined fuel like electriciity in order to burn it again is "greener" than converting NG to heat energy onsite at 98% thermal efficiency.

Thanks for the insight!
Do you feel we could base our main system off the mini-split and just do radiant on the basement slab and be happy?
Could we possible just do a hot water heater for the radiant to keep cost down to take the chill out of the basement and use the mini-split as our main source for heating?
Either way I am going to spend the money to run tubing in the basement, but my cost is in the boiler as well as in the pour of gypsum cement on the main level.

We design combination systems using various water heaters for space and DHW, not 'open' of course. We prefer a condensing water for this duty but putting PEX in a slab is standard procedure and one of the few ways to make a basement truly comfortable. If the loads are right this is ideal since the main level can heated from with a sub-floor, sandwich or "wet" system such as Gypcrete. Once you have a proper heat load the options become clear.

Here in Minneapolis you will find thousands of new homes with a water heater such as a Bradford White Combi-Cor providing DHW and heating the basement slab, while a standard scorched-air furnace serves the upper floors in the old-fashioned way. We often see the master suite bathroom with PEX mud-set under tile as well. This small load would be an unacceptable micro-zone but the added mass of a high efficiency storage water heater works as a thermal buffer tank and makes small zones/loads easy to handle with good efficiency and performance.

drip:

A basement slab running of a hot water heater (or an electric boiler) controlled by a slab-thermostat, with the bulk of the space heating sourced by ductless mini-splits is definitely a workable option in southern Ontario.

I know of some folks in Quebec heating solely with Fujitsu XLTH-series mini-splits who did just fine, down to -33C/-27F this season even without the radiant floor.  The Mitsubishi MSZ-FHxxNA series is comparable, but has somewhat higher efficiency numbers.  Both have fully specified output at -25C, but keep on going no matter how cold it gets.  At -25C they are still about 2x as efficient as an electric boiler.

Have you tried downloading and using NRCAN's Hot 2000 heat load tool? I haven't looked at it in detail to see how flexible it is when dealing with high-R structres, but it's a pretty straight-ahead sort of tool.

Morgan:  As mini-splits have gotten better and as Bob_I's ISO-New England grid has gone to about 50% of all kwh delivered on an annualized basis being sourced by combined cycle gas at thermal efficiency hair better than 50% thermal efficiency, the average efficiency of fossil-to-heat into the room does indeed beat condensing gas boilers during off-peak hours, and has an even lower overall carbon footprint due to the mix of the other 50% (off peak or on.)  Absolute demand peaks on this grid are still air conditioning peaks, not heating season peaks, and the AM bump is predictable & manageable with the combined cycle resource during the winter season.   If the grid was sourced solely by 50% thermal efficiency cc-gas you'd be looking at better than 100% fuel-to-heat-delivered efficiency as a seasonal average, though during absolute coldest design-day hours when the mini-split is only pulling a COP of 1.8-2 it'd would be in the 90%  range, sort of like a mod-con on the edge of condensing. 

You can't get that kind of thermal efficiency out of the coal fraction of the grid, but coal BTUs have become more expensive than natural gas BTUs, which is cutting into the capacity factor of coal plants in this region due to the higher clearing price on the day-ahead market they need to operate the coal plants.

If you want to take snapshot-peeks at the mix on the ISO-NE grid, they have a nice l'il widget page showing the fuel mix and a bunch of other data over the most recent 5 minute interval. It looks very different between midnight and 6 AM when the heat loads are peaking but the grid demand is way below peak than it does during  the business lunch peak & plateau, or the 5PM to midnight "NetFlix & microwave popcorn for dinner" surge.  Over the past 5 minutes it was about 38% nuke, 35% natural gas, 15% coal, 4% hydro, and 8% from the mix of other renewables (the vast majority of which is from burning wood & garbage biomass), but for the bulk of the colder hours it'll be mostly nukes & c.c. gas, with the mix changing over the weeks with the spot-market price for natural gas.  The growth of solar PV is growing exponentially in southern New England, doubling every 2 years (as opposed to every 3 years nationally), and will likely become a double-digit percentage of the demand-hours grid source by 2020.

Bottom line, even thermal coal in a 35% efficiency plant can come close to condensing boiler efficiency when leveraged by best in class heat pumps, and it only gets better from there.  In the upper midwest even wind power is carrying most of the overnight load on many days, and the bulk of the space heating fuel use is overnight. Within 15 years grid storage will have been deployed to the point that low efficiency peaker-plants are going to have vanishingly small, and baseload generators will be able to always be operating in their most-efficient operating points, boosting the average operating efficiency of the c.c. gas burners to near 60%.  A 60% generator leveraged by a heat pump operating even at a COP of 1.8 (like a 5 year old Mitsubishi FExxNA at -13F outdoor temps) still beats the best boiler on net efficiency, since that'll be north of 100%.

Wait one minute! Are you trying to put me out of business? heheheee

I might go for an air-to-water heat pump so I don't have to give up my radiant floors, but straight up Mini-Split, no way!

Great information as usual. I am not as optimistic about future carbon footprints as you are, like Sweden, we depend heavily, and are reaping huge rewards, (financial and ecological) from nukes--however unpleasant the reality may be for some.

I am all for energy diversity, but have yet to see wind or PV heating homes here in Minnesota. Short of a Passive House, I don't see the revolution. What I see everyday in the field, is people trying to stay warm and get a handle on their fuel bills. Where natural gas is available natural gas appliances rule. In more moderate climates, those with a more balanced heat to cool loads, mini-splits and GSHP make more sense, economically and ecologically.

As for future cost. The gas goes down as the electricity goes up and infrastructure, something we depend on government for, is lacking. I don't believe my mini-split is a a sure thing, but it is a good hedge and a sound investment. If NG was available a condensing boiiler would be heating home and DHW but a heat pump is in the works. All are pricey at the moment and their day may be coming, like thermal solar panels.

http://www.forbes.com/sites/williampentland/2013/01/02/the-perverse-economics-of-the-electric-grid/

http://www.businessweek.com/articles/2014-02-06/northeasts-record-natural-gas-prices-due-to-pipeline-dearth

My 2 cents....

Electricity can be generated from a number numerous methods ..... this is the reason electricity is in a way considered to be what will drive the future.

If your using any of the various natural resources such as natural gas/propane/coal/heating oil etc ..... these fuels can be quite volatile in price therefore can not expect prices to be consistent year to year. If you use any of these fuels you will be taken advantage of from time to time as we have seen in the past.

The only consistent pricing we have seen in our life time for energy is electricity. Electricity can be derived from what ever the cheapest carbon based fuel is available at the time.

Obviously from my statements I am Pro Electricity and my choice in heating and cooling a home in a mild climate is a common air to air heat pump utilized duct work with automated dampers for zoning. From what I'm hearing your typical American HVAC company's are very close to releasing systems which work with dampers for zoning as they should have from the start, which will out perform mini split systems on various levels with much lower maintenance overhead. So watch out mini split fans the game is about to change.

So watch out mini split fans the game is about to change.

Forced air doesn't work so well in newer, properly built homes. Looking forward to the comparison of the new units you are shilling for.

Best way to deal with allergies/asthma is to get tested by a doc identify what they are, take shots. If your home is constructed with one of the allergies no HVAC/ventilation system will solve it, it could perhaps make it worse. There is no such thing as permanently exhausting a reactive chemical or allergies to air from an inside or outside source. A balanced HRV w/returns in every room is helpful for IAQ.

Foam is a known source isocyanates, especially oc sprays. Goggle net for law suits popping up. Some like XPS claim to have 'natural skins'. I don't trust them unless they are buried and sealed in a wall/roof sandwich construction. Fire retardants another.

Another movement along w/ passive and 2012 ICEE is low cost earth building w/o the VOCs that use mass effect and shifting thermodynamics, r-values do not apply, DBMS (Dynamic Benefit Mass Systems ORNL) developed does. The proper mass.solar designs need little HVAC is the harshest hot/cold climates, best with good diurnal swings but, not necessary if foam is a core element latest test are showing. Most with allergies are heading that way, another resurrection with new tech that sustains for centuries and millenniums proven mainly outside USA at a low COP. Check out this beautiful rammed earth home built for allergies and a healthy enviroment: https://www.youtube.com/watch?v=0RnJZq9rbL8 SIREWALL check them out.

Ducts with valves that collect nasty dust mice stay away from .

I'm with you guys on the lack of knowledge out there in "professional' mainstream building America.

Posted By ICFHybrid on 10 Mar 2014 11:56 PM

Forced air doesn't work so well in newer, properly built homes...

Why?

http://www.sirewall.com/portfolio/residential-projects/otter-limits/

Check out this natural wall, some 24” that utilize thermal mass. This one with no solar effect, a power outage during below freezing temps left the house from 20°-14.5°C (68°-58°F) for 4.5 days from loaded HVAC mass with the right specific heat, density, thickness, lag time. I’ve seen other examples with concrete 10-12” (CIC). When you are pouring, shooting, or casting monolithic stand-alone structure with continuous foam core insulation, walls/cathedral-vaulted roofs with massive skins, that provide the best continuous structural and thermal load paths, prevent thermal bridges, air seal by design default, maximize thermal effect, reduce labor and materials cost, it becomes unnecessarily, difficult, and costly to run inefficient HVAC ducts. Minisplits single zone most cases, wood burners, work fine. Some are running PEX through interior mass to geothermal.

Posted By arkie6 on 11 Mar 2014 02:45 PM

Posted By ICFHybrid on 10 Mar 2014 11:56 PM

Forced air doesn't work so well in newer, properly built homes...

Why?

He's like a old mule with blinders....

r-values do not apply

Except in some generally rare climate conditions, r-values always apply.

steady state r-values resistance do not apply to thermodynamics anywhere in the world, it is far more complex than that. We don't live in steady state environments, nor do walls. We run it all day, CFD and FEA models, then we validate those models to lab and field data. Q formula has many variations, look it up....then get into aerodynamics, human factors, and equipment correction factors, commercial vs residential, you need a model better than WUFI and HVAC loads.

Read this about DBMS value: http://web.ornl.gov/sci/roofs+walls/research/detailed_papers/thermal/index.html

Read this on the latest how r-value is misleading this industry. If you need help with the test procedures and results let me know it is what I do for a living. I'm doing thermal, pressure, fatigue life cycling on seals now. http://www.buildingscience.com/documents/special/content/thermal-metric/BSCThermalMetricSummaryReport_20131021.pdf

Good read take note: "This article does not address the use of thermal mass inside a building, where it can store heat (or coolth) and even out temperature fluctuations".
http://www.buildinggreen.com/auth/article.cfm/1998/4/1/Thermal-Mass-and-R-value-Making-Sense-of-a-Confusing-Issue/

Posted By BadgerBoilerMN on 10 Mar 2014 06:41 PM
Wait one minute! Are you trying to put me out of business? heheheee

I might go for an air-to-water heat pump so I don't have to give up my radiant floors, but straight up Mini-Split, no way!

Great information as usual. I am not as optimistic about future carbon footprints as you are, like Sweden, we depend heavily, and are reaping huge rewards, (financial and ecological) from nukes--however unpleasant the reality may be for some.

I am all for energy diversity, but have yet to see wind or PV heating homes here in Minnesota. Short of a Passive House, I don't see the revolution. What I see everyday in the field, is people trying to stay warm and get a handle on their fuel bills. Where natural gas is available natural gas appliances rule. In more moderate climates, those with a more balanced heat to cool loads, mini-splits and GSHP make more sense, economically and ecologically.

As for future cost. The gas goes down as the electricity goes up and infrastructure, something we depend on government for, is lacking. I don't believe my mini-split is a a sure thing, but it is a good hedge and a sound investment. If NG was available a condensing boiiler would be heating home and DHW but a heat pump is in the works. All are pricey at the moment and their day may be coming, like thermal solar panels.

http://www.forbes.com/sites/williampentland/2013/01/02/the-perverse-economics-of-the-electric-grid/

http://www.businessweek.com/article...ine-dearth

The wintertime grid in the ISO-NE region is mostly nukes with the cc gas and coal taking up only about 1/3 of the grid share. The renewables slice is bigger than the coal slice most of the time, and growing.  The cc gas burners kick into more continuous and higher output during the summer. I'm not at all worried about the the spiky spot market price for n.g. to drive wintertime rates for either electricity or residential gas up very far or fast. As the Forbes article points out, the distribution cost is half (sometimes more) the total per-kwh cost to the ratepayer, and at the wintertime grid mix the gas-fired kwh are half the summertime share. Even if the fuel cost of that gas-fired fraction went up by 50%, it would mean at most a penny per kwh to the ratepayer at the winter grid-share. If the gas supply bottlenecks persist into July (not likely since the space heating load goes away) it could mean higher rates during the cooling season. I'm not convinced it's worth spending a huge amount to upgrade the gas-grid infrastructure to supply even more gas-fired generation in the ISO-NE region at this point, but it's been a hot topic of discussion for the past 3-4 years, heating up more recently due to the ~10% higher than average space heating loads in the region this season. (But more heat pump solutions to space heating would free up more gas for power generation, since they operate with higher net thermal efficiency across the grid than the average home heating boiler/furnace.)

To see the most recent 5 minutes grid-mix in the ISO NE grid, as well as the levelized (line losses factored in) spot market price for wholesale electricity, check out their handy li'l web-widget page.   In the middle of the day in winter it's about 1/3 nuke, 1/3 gas, 1/3 other.  Over the past 5 minutes (it will have changed by the time I finish typing, or by the time you click the link) it's 39% nuke, 36% gas, 11% coal, and 14% renewables. The renewables broken down are 4% hydro, 2.5% wind, 3.9% wood, 3.3% trash incineration, and 0.3% landfill gas. The spot-market price is currently 4.5 cents/kwh- it dropped to about 1 cent/kwh  a few times during the middle of the day since the load-reality undershot the predicted grid load by quite a bit, so all but the renewables were losing money during those periods. At night it's mostly nuke & renewables, with the nukes operating at a net financial loss, they do that to be able to make money during the following day, since if they ramp down they are unable to ramp up at a sufficient rate when demand picks up.  Even at 4.5 cents spot market nukes are losing a bit of money, since just their fuel costs are somewhat more than that, but even a half-hour of 27 cent/kwh like there was during the AM ramp can make up for a whole day of very marginal losses. Even at $6MMBTU spot market gas the combined cycle plants are making good money at 4.5 cents.  Most of the renewables keep making money even at 1-cent, since their marginal costs are effectively zero- their costs are primarily in their financing, which is fixed and known over time, and cranking out the marginal power even at 1 cent/kwh is still better for them financially than not-producing during the low-demand periods.

Installing widely distributed generation, whether gas-fired cogenerator, rooftop PV, or grid storage unit (battery or other) disbursed  across the grid lowers rather than increases the loads on the grid, and done right, makes it more stable.  The costs of stabilizing distributed wind and solar are proving to be cheaper then upgrading the capacity of the grids with fatter wire, etc.  In Texas this week Austin's local utility just made a 25 year power purchase agreement with a distributed solar company (Sun Edison, in this case, a company that effectively rents your rooftop by giving you a break on your power rates, but also builds utility scale solar arrays) at less than a 5 cents/kwh, a locked in contract price immune from fuel price volatility and spot market electricity prices.  (And SunEdison was just one of 30 bidders hitting in that range!)

That sub-5 cent contract is surely going to beat the spot market price averages from other sources over the next 25 years, and it's saving them from at least some of grid infrastructure upgrading costs.  You might be able to fuel & maintain a legacy nuke with that nickel, but you sure won't build a or decommission a new one with that!  Austin Energy is probably one of the best utilities for being able to surf the PV and distributed generation tsunami with style rather than getting crushed by it.  PV pricing trends are already well on track, and as distributed storage hits certain price points the financial argument for micro-gridding and self-islanding becomes compelling, especially in comparison to the costs of upgrading the traditional large power generator hub & spoke grid to manage future load growth.  We're not there yet in most of the US, but in Germany it's already happening. Some utilities are already too late to the party to survive.

Given that more than 25% of all kwh shipped in Iowa & South Dakota are from wind, and wind power is growing rapidly in Minnesota, don't be convinced you've never seen a heating system powered significantly by the wind.  You probably have, but just didn't know the grid sources at the hour it was wind-powered. (Got geo? How about an electric boiler?) MN is also looking at Austin Energy's Value of Solar Tariff (VOST) analysis as the model to tweak the relevant factors for in MN.  Solar is still below the radar there, but as the price of PV falls well below that of wind and cc. gas, even in cheap-power MN the PV wave will eventually hit. It'll hit sooner after the VOST structure is in place, where the distributed PV operators are compensated for the amount of infrastructure upgrading they offset and the utility is properly compensated for hooking them up, etc.  Just as in New England, it's still the thin edge of the wedge in MN, but with PV it's exponential growth nearly doubling every two years. If it's 1% of the grid share today it's 2% two years from now, 4% four years from now, and 8% in six years, 16% in eight, and at the end of a decade it's challenging cc gas for total kwh shipped. Sure, we'll run out of appropriate rooftops & open spaces at some point, but all credible analysis points to PV being able to covering nearly all of the peak load, and  double digit percentage of all kwh shipped before that happens, and is expected to be by far the cheapest grid power out there well before 2030. (By then grid storage is expected to be well under $100/kwh too- it's going to be a strange new world.)

Posted By TLP on 11 Mar 2014 05:47 PM
steady state r-values resistance do not apply to thermodynamics anywhere in the world, it is far more complex than that. We don't live in steady state environments, nor do walls. We run it all day, CFD and FEA models, then we validate those models to lab and field data. Q formula has many variations, look it up....then get into aerodynamics, human factors, and equipment correction factors, commercial vs residential, you need a model better than WUFI and HVAC loads.

Read this about DBMS value: http://web.ornl.gov/sci/roofs+walls/research/detailed_papers/thermal/index.html

Read this on the latest how r-value is misleading this industry. If you need help with the test procedures and results let me know it is what I do for a living. I'm doing thermal, pressure, fatigue life cycling on seals now. http://www.buildingscience.com/documents/special/content/thermal-metric/BSCThermalMetricSummaryReport_20131021.pdf

Good read take note: "This article does not address the use of thermal mass inside a building, where it can store heat (or coolth) and even out temperature fluctuations".
http://www.buildinggreen.com/auth/article.cfm/1998/4/1/Thermal-Mass-and-R-value-Making-Sense-of-a-Confusing-Issue/

Of course it's more complicated that that, but just because mechanics is more complicated doesn't mean that gravity doesn't apply. The steady state R is just one element of a more complicated equation, but that fact doesn't mean "...steady state r-values resistance do not apply..."  Of COURSE it applies!

Although R-value is an extremely crude model, at best a first-order approximation,  it's far more than a third-order factor in a building's thermal performance, and more important than the thermal mass factors in most buildings.

High precision isn't usually necessary (and not really possible) to achieve useful and appropriate numbers in these analyses.  U-factors for wall assemblies calculated on the steady state R-values of the components are sufficiently predictive of the heat transfer rates to model annualized energy use and peak energy use of simple buildings like single family homes with corrections for other factors like plug loads, solar gain, etc.  Even a Manual-J or I=B=R tool will get you most of the way there, and a 2-D model like DOE-2 does a little bit better. None of them are capable of factoring out the human-behavior aspects, and all of them are "good enough", for most real-world purposes.   The most perfect thermal modeling of a house is readily undone by a single occupant who didn't understand that they needed to comply with the operating behavior that was modeled.

Nah, I wish I could show you my CFD model, it cost around $15, 000 license decent but not the best, then walk you over to our lab, few million in test equipment, if I were to call thermal mass of a building any other word but dynamics, it be thermal inertia but that be as misleading as r-value....take a while to load, then little to maintain for the materials we are referring to. Very hard to quantify, I think ORNL has a good start using the same lab instrumentation and field data we do, not much theory! Read the test reports on r-value BSC did...it is dynamics not steady state. What matters is the materials specific heat primarily not resistance.