This Article Is About Net-Zero Homes.  Al’s Plumbing, Heating & A/C, in Plano, Texas provides full service plumbing maintenance, repairs and replacements for every plumbing component in your home.  Al’s sells and installs Rheem Professional Series gas & electric water heaters, and tankless water heaters.  Al’s Plumbing, Heating & A/C is near your home in Plano, Allen, and Frisco.  We service all homes in southern Collin and Denton Counties with no additional travel charge.

Net-Zero Homes Are Extremely Energy Efficient PLUS Have Solar Collectors so they can provide their own electricity.  A Net-Zero home provides as much electricity to the power grid as it uses over the course of a single year. 

Net-Zero Homes are so; well insulated, air-tight, and energy efficient that they produce as much electricity as they consume over the course of a year, leaving the occupants with a $0 energy bill and a carbon-free home.   A Net-Zero home is 10% more expensive to build.  That difference will be repaid with $0 energy bills + the home’s resale value will be higher.

Over the course of one year, an ALL-ELECTRIC,  Net-Zero home must add as much electricity TO the Power Grid as it removed FROM the Power Grid (during times of peak demand for A/C or (electric) Heating.   True Net Zero Homes do not have natural gas powered devices, they are all electric. 

Image Source:  Flickr

SHOWN: The Gold Medallion Home Badge That Still Exists On Many Homes Today

All Electric Homes — What Is Old Is New Again…

Starting in the late 1950’s — early 1970’s, the “Live Better Electrically” (LBE) campaign extensively advertised & promoted All-ELECTRIC homes.  In October of 1957, the National Electrical Manufacturers Association (NEMA), launched the “Medallion Homes” campaign.  A home that met the requirements for a Gold Medallion Home had a “badge” affixed near its front door.   This let everyone know it was a Gold Medallion, All-Electric home.  Entire neighborhoods of Gold Medallion, All-Electric Homes were built across the United States.  One DFW Gold Medallion Homes location is the Lake Highlands area.

To earn the Gold Medallion emblem, the all-electric home had electric; heat, water heater, cooking appliances, and wired for an electric dryer).  Gold Medallion Homes also included built-in lighting.   150-Amp electrical service was required, and there was a specified number of outlets & switches per linear foot of wall space.

HydroPower Dams

Originally, the electricity needed for these all-electric homes was to come from the building of HydroPower Dams.  Over time, the ecological detriments caused by HydroPower dams became known.  A study from Washington State University found that methane gas, which is 72 times more potent than carbon dioxide (both are greenhouse gases) makes up 80% of the emissions from water reservoirs created by HydroPower dams.

The building of HydroPower Dams peaked in the 1960’s, with only a few dams built during the 1970s.   Only 3% of the reservoirs in the US are equipped to produce hydropower.   Today 13% of all electricity generated in the U.S. is Hydro-Electric.

One well known HydroPower Dam & Reservoir is the Hoover Dam near Las Vegas.  Lake Mead is the reservoir created by Hoover Dam.  Lake Mead is the largest HydroPower reservoir in the United States.

There Are Also Rivers With HydroPower Dams.   A quite large concentration of HydroPower dams on rivers is along the Columbia River in the Pacific Northwest.  The Columbia River is ideal as a HydroPower river because it flows through multiple mountain ranges during its 1,214-mile journey toward the sea.  The river and its tributaries receive water from millions of acres snow melt runoff each year.

Today there are 14 dams on the Columbia River, 3 in British Columbia (Canada) and 11 in the United states.  The majority (90%) of the Northwest’s renewable energy comes from hydropower dams, which generate carbon-free electricity without releasing measurable amounts of methane.

Source: https://www.bentonpud.org/About/Your-PUD/Special-Interests/Snake-River-Dams/Fast-Facts-The-Columbia-Snake-River-Hydropower-Sy

The Tennessee Valley Authority (TVA) operates 29 HyrdroPower dams throughout the Tennessee River system.  The Army Corps of Engineers owns 8 HydroPower dams along the Cumberland River.   The Cumberland River flows roughly parallel to the Tennessee River, south from Kentucky, across upper middle & west Tennessee, and western Kentucky.  It empties into the Ohio River.

HydroPower Dams, What Goes Wrong?

HydroPower Dams Can Create Conditions Resulting In Significant Greenhouse Gasses (Carbon Dioxide & Methane Gas) being released into the air.  Greenhouse gasses enter the atmosphere primarily through burning of fossil fuels and decomposition of solid waste, trees & other biological materials. 

The Intergovernmental Panel on Climate Change states that methane has a warming impact 72 times higher than carbon dioxide (when measured over 20 years).  One year’s methane emissions from large dams have a global warming impact equivalent to 2.6 billion tonnes of carbon dioxide.

By Comparison:

• 26.6 billion tonnes.  Global CO2 emissions from fossil fuel burning (in 2004).
•   2.6 billion tonnes.  Global CO2 annual equivalent of methane gas emissions from dams.
•   0.5 billion tonnes.  Global CO2 emissions from aviation (in 2002).

Source: https://www.internationalrivers.org/resources/greenhouse-gas-emissions-from-dams-faq-4064

The “fuel” for the methane & carbon dioxide emitted by dams is the rotting of the vegetation & soils flooded by reservoirs, and of the organic matter (plants, plankton, algae, etc.) that flows into, and is produced in, reservoirs.

In general, HydroPower produces little carbon dioxide.  However, large, shallow RESERVOIRS (especially in the tropics) can generate large amounts of greenhouse gases from the decay of biomass along the edges of the reservoirs (see Brazil’s Balbina Dam details below).   The amount of greenhouse gasses emissions produced by a HydroPower dam are entirely dependent on the nature of the land that is flooded. 

Source: http://www.ehso.com/ehshome/energydams.htm

When a RIVER is blocked, water gathers behind the dam, creating an unnatural & stagnant reservoir that often kills off a lot of the existing ecosystem. The excess water is pushed onto the river’s banks, which are often covered in plant life.  These plants are immersed and die.  Bacteria in the water decompose these plants, generating carbon dioxide and methane gas.

**** Source: https://qz.com/797380/reservoirs-methane-emissions-climate-change/

Seasonal changes in water depth (caused by HydroPower dams) creates a continuous supply of decaying plants that grow along the banks of the reservoirs during winter (while the reservoir’s water level is lowered due to decreased electricity demand).  In the summer, these plants become immersed when the water level rises, causing them to die and decay.  *****

***** Source: https://www.theguardian.com/sustainable-business/2016/nov/06/hydropower-hydroelectricity-methane-clean-climate-change-study

Per Killowatt-Hour (kWh) Carbon Dioxide Emissions Equivalent For Each Power Generation Plant Type:

• 0.145 pounds (2.3 ounces).  Nuclear Reactor:  CO2 equivalent per kilowatt-hour (kWh). *8

• .754 pounds (3/4 pound): Large-scale, Hydropower plants built in Semi-Arid regions: *9

• 0.6 — 2 pounds: Natural gas generated electricity *7
• A high-efficiency natural gas power plant produces less greenhouse gas emissions than the more efficient HydroPower in Semi-Arid regions.

• 1.4 — 3.6 pounds: Coal generated electricity. *7

• 4.5 pounds:  — Brazil’s Balbina Dam which floods 1,465 square miles of Tropical Forest to generate 112 MW of electricity. *9
• That’s as much as 3 (high efficiency) coal fired power stations.

• *4 Source: https://www.newscientist.com/article/dn7046-hydroelectric-powers-dirty-secret-revealed/
• *5 Source: https://en.wikipedia.org/wiki/Dam_removal.   This source lists several dam removals.
• *6 Source: https://www.ucsusa.org/clean_energy/our-energy-choices/renewable-energy/environmental-impacts-hydroelectric-power.html
• *7 Source: https://www.bizjournals.com/denver/blog/earth_to_power/2014/01/natural-gas-power-plants-produce-40.html
• *8 Source: https://journalistsresource.org/studies/environment/climate-change/nuclear-power-greenhouse-gases/
• *9 Source: https://carbonfootprintofnations.com/2013/09/17/carbonfootprintofhydropower/

Today’s Renewal Energy Sources Are Wind & Solar “Farms”. 

Additionally, “Battery” Farms Are Being Added At Various Locations. 

Battery Farms Allow The Electricity To Be Stored Until Needed. 

Power-Grid Sized Battery Farms are required to ensure constant electricity supply as more intermittent renewable power generation (wind & solar) continues to grow.
In 2016, 3 Gigawatts (GW) of energy-storage capacity existed.  By 2022 that number is expected to be 28 GW, and 52 GW by 2025.  In Escondido, California, a 30 MegaWatt (MW) energy storage facility is currently online.  This facility stores the energy equivalent of serving 20,000 customers for 4 hours.

Lithium-Ion Batteries currently account for 95% of Energy-Storage installations.  Falling prices for these batteries is occurring as Tesla (car manufacturer), Toshiba, Panasonic and Asea Brown Biveri (ABB) ramp up production, and achieving production economies of scale (the more you make, the less expensive they become).

Click Here To See A Combination Wind & Battery Farm: Wind & Battery Farm In Southern Australia

Net-Zero Home

Net-Zero (All-Electric) Homes Produce Their Own Electricity (nearly all of the time). 

Net-Zero homes are also all-electric.  Unlike their Gold Medallion predecessors, Net-Zero homes are extremely energy efficient PLUS have solar collectors that provide their own electricity.  During times of peak air conditioning or (electric) heating demand, Net-Zero homes draw additional electricity from the Power Grid.  During times of low demand, these homes provide power TO the grid.  Over the course of 1 year, a Net-Zero home must provide as much electricity TO the Power Grid as it removed.

Image Source: Pixabay.com

Copy The Link Below To See A Summary Of What Is Required For A Net Zero Home Certification

https://www.energy.gov/sites/prod/files/2019/04/f62/DOE%20ZERH%20Specs%20Rev07.pdf

Net-Zero Energy Certified Homes are built to higher energy-saving standards as Energy Star Certified Homes PLUS have Solar Collectors on the roof.   A true Net Zero Home is all-electric home, is connected to the power grid, and is never connected to natural gas.

• During times of higher household electricity demand (higher than the solar collectors’ ability to generate it) the home will get additional electricity from the power grid.
• During times of lower however electricity demand, the home will put excess electricity into the power grid.  Over the course of 1 year, a Net-Zero home will replace all electricity it used.   Hence, the name Net-Zero OR Zero-Energy Home.
• Over the course of 1 year, the home will generate credits for electricity it provided to the power grid.  These credits pay for electricity bought from the power grid,  thus eliminating electricity bills.
• A true Net-Zero Home is not connected to natural gas, it’s an all-electric home. .

Net Zero Homes do not have a “Carbon Footprint”.   This means they do not have gas-burning devices, plus they generate at least as much electricity as they use during the course of 1 year.

Beginning On Jan 1, 2020 California Requires New Homes Have Solar Collectors On Their Roof

With The Capacity To Provide As Much Electricity As The Home Uses Over The Course Of 1 Year. *

Starting in January of 2020, California requires all newly constructed single family homes (and multi family buildings 3 stories or less) must have solar collectors on their roof.   The PV System must be sized to achieve Net Zero annual electricity usage * (produce as much electricity as the home consumes during 1 year).

* The 2020 California Net-Zero Electricity Demand Building Code assumes the home uses some natural gas, typically for heating & water heating. The Building Code applies to; lighting, appliances, and electrical devices.   It does not apply to heating or water heating.

* If a homeowner decides to build the home as all electric, they are not required add more solar panels (than if the home had gas heat).   Homeowners who choose to have the home all electric have the option to build a larger Solar Collection System to accommodate an all electric home, though not required.

Image Source: Pixabay

A Notable Step Up From Energy Star Certified Home

Net-Zero Home

Net Zero Homes In Colder Areas May Have Geo-Thermal Heating & Cooling, Plus Solar Panels For Electricity.

Image Source: ShutterStock

Click On The White Arrow In The Center Of The Photo Just Below For A Video Explaining Net Zero Homes.

Image Source: YouTube Embedded Video

There is no doubt that an Energy Star Certified home will have lower energy bills.  We have detailed all the reasons an Energy Star Certified home has lower cooling & heating demand than homes that don’t have the certification.

Click Here To Read About Energy Star Certified Homes:  AlsPlumbing.com Energy Star Certified Homes

A Net 0 Home has rooftop solar panels to produce all the electricity the home needs (over the course of 1 year).  They can be built almost anywhere, even in locations with brutal winters.  Net Zero homes in very cold climates typically have Geo-Thermal (underground sourced) heating and air conditioning.

Net-Zero homes are around 10% more expensive.  The extra costs to build a Net-zero home will be repaid with energy savings in under 14 years in most of the 50 largest U.S. cities.  **  Additionally, Net Zero homes will have a higher resale value.

Click Here To See Details How A Net-Zero Home Is Built:  Net-Zero House Diagram

As with Energy Star Certified homes, a Net Zero home must be certified by a 3rd-Party.  The most common certifications are from the Department of Energy’s Zero Energy Ready Certification, Living Building Challenge Zero Energy Certification, Passive House Certification, and Earth Advantage’s Zero Energy Certification.  Independent energy consultants can also provide third party verification of zero energy homes.

Click Below To Read The 6 Considerations When Building A Net-O Home in Texas:

Six Considerations When Building A Net-Zero Home in Texas

• 1. Occupant Energy Saving Assistance:

A home’s eco-friendliness is largely determined by the behavior of the occupants.  Net-Zero homes typically include a user friendly energy-monitoring system with internet access.

• 2. Orientation Of The Home:

In Texas, the best configuration for a Net-Zero Home is a long rectangle oriented with its long sides facing north-south. When designed & oriented correctly, a Net Zero home in Texas can get 75% percent of the heat it needs from the sun.  This orientation eliminates a home having a long side facing west during the heat of Texas summer.

Attention is paid to proper placement of windows and adequately shading them.   For instance, direct sun never shines through north facing windows, but shines most of the day through south facing windows.

• 3. Building Envelope: Insulation & Air-Infiltration Requirements. 

The “Building Envelope” Is The Barrier Between The Home’s Interior & The Environment.  This includes the walls, ceiling / roof, floors, windows and doors.  Eco-builders use  spray foam insulation as opposed to traditional batt insulation.   Foam insulation has the ability to fill small cracks & crevices which fully seals the building.

Insulation In Climate  Zone: DFW is in CZ-3 

• Net-Zero Requirement                   Texas Building Code
• Wall: R-20                                                R-15
• Attic R-50                                                 R-38
• Slab Floor R-20                                       R-19
• Windows U & SHGC  .30  & <.30      .35  & .25

With the exception of Attic & Wall insulation. requirements for Net-Zero and Texas Building Code are similar.  The addition of insulation and slightly superior windows would mostly meet Net 0 insulation requirements in DFW.

Air Infiltration In Climate Zone 3:

• Net-Zero requires no more than        2.5 Air Changes Per Hour (ACH)
• Energy Star & Texas no more than      5 ACH
• A Typical 1970 built home in DFW   17+ ACH

ACH is the computed number of Air Exchanges Per Hour during a Blower-Door Test (a Blower-Door Test creates a vacuum inside the home).

• 4. Whole House Air Purification System

Net-Zero homes are extremely air tight.  This could lead to unhealthy Indoor Air Quality.  Eco-Builders typically install a Whole House Air-Purification System.

• 5. High Efficiency HVAC System, Appliances & Lighting

The largest users of energy in a home are; cooling, heating, & water heating.  Next are large home appliances (dishwasher, cooking, and laundry).  Another large energy use is lighting.  A Net-0 home employs High Efficiency; HVAC, Appliances and Lighting.

• 6. Solar Energy For Electricity Generation

The Most Prominent Technology Employed To Achieve Net Zero Is Solar Energy Collectors. This technology, over the course of 1 year, eliminates electricity bills for the home owner.  The home is connected to the Power-Grid for times when the solar collectors cannot provide all the electricity needed.  During times of lower household electricity demand, the collectors add electricity into the Power-Grid.  This provides credits that pay for electricity needed during high-demand times (such as summer and very cold times during winter).

Net-Zero Requires The Home Does Not Directly Nor Indirectly Produce Carbon Emissions Over The Course Of 1 Year.  Therefore, a Net-Zero home cannot have natural gas heating and appliances   Over the course of 1 year, the home’s solar collectors generate enough excess electricity (sent back into the Power Grid) to replace the electricity taken from the Power Grid during times when the solar collectors can’t keep up with demand.  This results in no energy bills for the owner.  Additionally, with the right landscaping + rain water collection (and possibly gray water collection) ** meets the lawn’s irrigation needs.

** Gray water is water collected from; bathtubs & showers, bath sinks, and laundry rooms.  It can be used for lawn irrigation.

In some cases, a home is built to Net-Zero Energy-Efficiency Standards, but does not include solar collectors.  The home is built so the collectors can be added easily at a later time.  This would not qualify as a Net-Zero home unless the Solar Collectors are eventually added.  It does have superior energy-saving performance over even an Energy Star home.

There are many custom Home Builders who build Net-O homes.  There are also some major & national Home Builders. In Texas, they include Meritage & KB Home.

Click Here To See Net-O Home Builders In Each State: Net-O Builders In Each State

• Xeriscaping Plus Rainwater (& perhaps Gray Water) For The Lawn

“Xeriscaping” is using drought-resistant landscaping that is adapted to the local climate of various regions.  Xeriscaping, combined with rainwater (and perhaps gray water) collection & storage systems can meet a net-zero home’s lawn watering needs.

Grass Types In DFW:  St. Augustine grass is common in DFW.  St Augustine requires 50 — 100% more water than other grass types.  Common Bermuda grass is also extensively used in DFW.   It is more drought-resistant and good for lawns which have some shade.    Celebration Bermuda is drought tolerant, more durable and and is very soft.  It does better in shady areas than Common Bermuda.   Zoysia is good for lawns with a lot of shade and can be mowed quite low.  Buffalo grass is the only common lawn grass native to Texas.  It does well in the heat and, with irrigation, will stay green throughout the summer.  It does not hold up well to foot traffic.

**Source: https://insideclimatenews.org/news/10122018/net-zero-energy-efficiency-home-infographic-solar-pay-off-years-midwest-detroit-chicago-columbus

The Major Aspects Of A Net Zero Home May Include

• Geo-Thermal Heating & Cooling (in colder regions)
• Solar Panels For Electricity.  Home is also connected to Power Grid for times when the solar panels cannot produce all electricity needed.
• Automated Home-Energy Manager
• High Performance Windows & Doors
• Very Well Insulated & Air-tight

In Net 0 Homes: Wall insulation values are R-19 in mild climates.  Texas Building Code requires R-15.

For ceilings the insulation value can be R-50 for mild climates, R-60 for cold climates, R-80 for very cold climates. For floors, insulation levels can be R-38 in cold climates, R-60 in very cold climates and R-19 in mild climates. For an extreme example, in Alaska insulation in the walls has been used up to R-90 and in the ceiling up to R-140.

• High Performance “Building Envelope”.  The building envelope is the outer shell of the home.  Net Zero includes; an air-infiltration barrier and extreme attention to detail to ensure all air leaks are sealed during construction.
• Low-Flow Water Fixtures.
• Rain Water & Gray-Water Recovery.  Gray Water is the waste water from only the; sinks, showers, and washing machine.  This water is used for lawn irrigation (some homes also use it for toilet flushing).

HERS: Home Energy Rating System

A Typical Net Zer Home Is Built To A HERS = 55  (or lower).  Then, The HERS Is Reduced To Zero With The Addition Of Solar Collectors. 

HERS is the Home Energy Rating System. It is a standardized rating that boils down the home’s energy efficiency into a single number.   The HERS score is compared to a home that meets minimum Building Codes for Energy Efficiency.    A certified Home Energy Rater assesses the energy efficiency of the specific home, then assigns its HERS score.

The HERS Score Is Affected By:

• How air-tight the home is (how much air it leaks)
• How much insulation it has
• The caliber of the Windows & Exterior doors
• Energy Efficiency of the HVAC System
• HVAC Ductwork – Degree of Air-Tightness
• Energy Efficiency of the Water Heater
• Energy Efficiency of some of the Appliances, & Lighting

• A new home built to minimum 2018 Building Codes: HERS = 100.
• An Energy Star Certified home:     HERS = 85.
• A typical new home built in 2017:  HERS =  62.      A typical 2017 home consumes 38% LESS energy than one with minimum Energy Building Codes.
• A typical new home built in 2006: HERS =  85.      A 2006 home consumes 63% more energy than a typical new home built in 2017.
• A typical new home built in 1970:  HERS = 104.     A 1970 home consumes 68% more energy than a typical new home built in 2017.
• The average for all used homes:  HERS =  130.   The average for all used homes is 210% more energy than a typical home built in 2017.

• Net Zero Homes work to attain a HERS Index of around 55.  Then, they achieve HERS=0 with solar collectors.
• The 2019 Lowest HERS Index Score For a U.S. Production (Tract) Home Builder: HERS = 42: Lennar Homes Of Minnesota.
• The 2019 Lowest HERS Index Score for a U.S. Custom Home Builder: HERS = 32:  Vetting/Wolf Home, Minnesota.

** Source: https://www.builderonline.com/building/building-science/record-number-of-homes-received-hers-rating-in-2017_o

Al’s Plumbing, Heating & A/C, in Plano, Texas provides full service plumbing maintenance, repairs and replacements for every plumbing component in your home. Al’s sells and installs Rheem Professional Series gas & electric water heaters, and tankless water heaters.  Al’s Plumbing, Heating & A/C is near your home in Wylie, Murphy, and  Rowlette, TX.  We service all homes in southern Collin & Denton Counties with no additional travel charge.