More comfort with common cent$ first !
Self-insulating window panelsWindow Quilt ®
Insulating shades- back in business!Cellular Shades
Insulating shadesShade Cloth
Reduce summer heat and fading.
Detailed map specific to your situation to save energy
Solar Hot Water Systems
Cost effective and reliable with custom storage tank technology that can be assembled on-site in tight spaces!Solar Pool Heaters
Enjoy A Warm Pool.Photo Voltaic systems
The miracle technology of solar electricity
Systems we've installed
Flashed so that future roof maintenance is easy!
Energy efficient housing
The Founder and Principle Member LLC
Project and Installation Manager
Links and recommended reading
The Questions to ask and
concepts behind what we do.
CommonWealth Solar, LLC.
12433 Autumn Sun Lane
Ashland VA, 23005
(804) 798 5371
Table Of Contents:
Heat is lost to infiltration and air loss by over 3 times the amount it is lost due to ceilings. These categories generally stack up this way in terms of % heat loss in a home:
That is, put another way, insulation only insulates when air does not move through it.
Consider this example here of the green metal siding that obviously not only did not prevent air flow, it did not stop flying insects such as wasps from building their nests in the fiberglass "insulation" !
This insulation provided almost no benefit. Air filters for engines are sometimes made of fiberglass. Fiberglass provides no air barrier of its own.
Remember to compare these general percentages with the cost for each repair and keep in mind that blown cellulose insulation both insulates and reduces air leakage.
Insulation only works if there is an effective air barrier.
An independent auditor is the best first investment during planning for building upgrades because that auditor works for YOU and not for a commission on a bigger heat pump or more expensive windows etc.
Some tips on getting started with your own lifestyle and building shell "tuneup" (audit).
Energy Star listing of "Common Problems" (most of which will be qualified and quantified by a thorough energy audit.
Energy Star on Audits
Dominion Home Energy Calculator
How much pollution does your energy consumption generate?
(note: to find how much pollution an alternative energy source would save, just plug in the estimated kWhrs of energy replaced by your alternative energy source instead)
Also this includes the power line losses (estimated for your location!)
Home Energy Saver - Do It Yourself audit guide
"Consumers don't want to buy electricity or
One caveat to remember is that this simulates a very windy day. There are some instances where a house can be leaky but if the leaks are protected from the wind, it will still hold heat. But a Blower Door is a great place to start with quantifying the effectiveness of your house for holding heat and AC in.
Any audits you get on your building should include the Cubic Feet per Minute and the calculated Air Exchange Rate that comes from using a Blower Door properly.
Did the audit include the CFM and air exchange rate (number of exchanges per hour.) ?
converted to BTU's or Joules of energy for comparison of options. Keep this in mind if someone says "years ago I only paid $x to heat my house. Ahh, yes, but what was the price per BTU ?
superinsulating your windows. They can also come with a track to block air from flowing around the shades.
BUT ITS BEAUTIFUL AND RETRACTABLE!
[Click here for a demonstration]
Cellular shades are especially helpful on the north side of a house where you do not get any solar gain in the winter and thus want to keep your heat in, but cellular shades can also help control excess heating from the Summer Sun and keep your AC inside and the Summer Heat out!
Commonwealth Solar can install cellular shades for maximum cost-effective window insulation.
Central Virginia has a freezing climate so any water left up in the panels at night in the Winter or even Spring or Fall will likely freeze and damage the pipes.
So option one is to have a sealed and pressurized loop like in your car that uses an antifreeze solution (typical ethelyne glycol or "food grade" Propylyne Glycol) that is filled all the time.
You should not drink antifreeze so a heat exchanger is absolutely required.
Option two is a "Drain Back" (not to be confused with "Drain Down") system.
As the name implies, as the sun and/or temperature in the panels goes down, the pumps stop and the water drains down into a holding tank that is safely within the protected shell of the building.
The pumps also stop when the tank has reached the high temperature cutoff point. The water in the panels drain back so that stagnation damage is far less likely.
Commonwealth Solar's drainback system has been tested by the state of Virginia* to collect and store more heat per square foot of collector than most systems and is not pressurized and so has less potential failure points than loop systems.
*John Randolph, Bob Schubert, Saifur Rahman, Yonael Tekiu, Virginia State Agency Solar System Monitoring and Evaluation: Final Technical Report , Virginia Polytechnic Institute and State University Blacksburg, Virginia prepared for Virginia Department of Mines, Minerals and Energy, Richmond, Virginia. May 1995
The first goal of any efficiency and conservation effort must include checking the ductwork for leaks.
Burying the ductwork where possible under cellulose insulation will help tremendously with both causes (conduction and convection) of heat loss from ductwork.
We have even seen very "affordable" installed ductwork that was LEFT WIDE OPEN, typically at the end of a house. We usually find those when the occupants complain that an end room seems to get little or no air flow from the registers.
But where the ducts are in the attic or even (horrors!) out in the outside air ... then proper testing, sealing and then insulating those ducts is vital.
If the house seems to be cheaper to heat with electric space heaters, this is a very important piece of evidence that your ductwork is hugely wasteful.
Two studies showed that ducted homes had 70 percent more air leakage and used 17 to 22 percent more energy for space heating.
An independent auditor is the best investment because that auditor works for YOU and not for a commission on a bigger heat pump or more expensive windows etc.
Exterior Insulation usually with foam panels provides a wonderful opportunity to use the "thermal mass" of your building to your advantage. Thermal mass is any heavy mass (like the thick walls of older municipal buildings, or a cave, for example) that change in temperature very slowly. Thus as you go into Summer, the cooler condition of the thick walls decreases your need for Air Conditioning. And then as you enter Winter, the left over heat from the Summer decreases the rate at which your house cools off.
Insulating the outside of a thermal mass, that is, a thick brick or concrete wall and/or foundation now means that effect is amplified because you have insulated your walls from the extreme heat of early Summer and the extreme cold of early Winter. As you run your Air Conditioning or Heating, it is now heating a wall that averages the outside temperature as well as absorbing as a kind of "thermal battery" your efforts to cool or heat your house to the temperature you want.
An added benefit is that in some cases there are many microscopic holes in the mortar that allow diffused air to be drawn through the brickwork!
So instead of "pointing" the joints in brick, another option that gives you energy efficiency benefit is to put on exterior insulation.
(For example, in one blower door test, we found a steady blast of air coming down a chimney. This was in spite of the fact that the top of the chimney was capped solidly. It turns out the mortar had failed to some degree, it needed pointing, and so the air was coming into the house through the mortar!)
then alternative energy production is a HUGE topic. This appendix entry only skims the surface.
The short version is that wealthy and healthy people combine
Put another way:
If a poor person can only afford the leaky $10 boots,
and they last a year
(and comes with wet feet from leaks),
A wealthy person can buy the $50 boots that last 10 years.
The poor person will have spent twice as much as the wealthy person at $100
and still have wet feet!
So now that we've decided we'd rather have dry warm feet at half the price, consider how to pay for toasty toes:
What is it worth to have more freedom from Energy Insecurity and all the trouble that addiction to energy has gotten us into?
An example webpage of an Energy Efficient Mortgage (EEM) at myEnergyLoan *
*Please note that Commonwealth Solar does not recommend any particular loan products. This is only an example.
See "Roof Flashing"
That is, unless you give your combustion device a "fresh air vent".
That fresh air vent gives your combustion devices (gas, oil or wood fired boilers, gas or oil hot water heaters, fireplaces) a place to get fresh air besides your air.
Another benefit is that your house doesn't dry so dramatically and your skin thus is not as dried out and not as likely to get nosebleeds from overly dry air. As the combustion device sucks up air for the burning of the fuel, it tpumps that moisture laden air out its exhaust or smokestack. This creates a vacuum in the house so you feel any leaks all the more dramatically . The cold air outside is drier than the warm inside air and so the overall humidity in your house drops thus drying out your skin and nose. Flaking breaking skin and nosebleeds often result.
A fresh air vent can also make a dramatic difference to your lung's health. There are various events and conditions (such as "stack effect" caused by air leaks into the attic) that can cause a lower air pressure in your basement than the smokestack of your combustion device ... and pulls the polluted exhaust into your living space ! The fresh air vent prevents that "backdrafting" that can sometimes kill you with pollution.
In this picture, you can see a "hydrostove" with a fresh air vent installation. In this picture the vent installation is not complete so you can see part of the vent ductwork laying on the floor for you to see. Even without the stove running, you could literally see the dust on the floor blow away from the open end from the air coming in from outside! The hydrostove helps make the wood burning more effective as well since excess heat at any one time is stored by the water tank. The hydrostove makes up for hot water not heated by the occasional multiple-day overcast event that reduced the solar panel effectiveness.
Heat pump hot water heaters make more sense than solar panels if there is very little hot water used, (less than 60 gallons a day used) such as an administrative office building one or two adults in a household with no jacuzzi.
For an analysis of heat pump hot water heaters, see this Washington State University study.
As a bonus, the heat pump hot water heater can:
For more information about a system we commonly use, see: http://www.aers.com/etech_residential_water_heating.html
Most Homeowner Associations (HA) are actually formed by the developer and not the homeowners. Some HA's are so restrictive as to consider flags, growing food or clothes lines as "eyesores"!! If you are unlucky enough to be stuck with such a HOA, there is hope.
Luckily satellite dishes are now exempt from those restrictions and so there is hope for sanity yet.
InsulationThe theory behind insulation is to slow heat transfer. This works regardless of the direction of the heat flow. Heat moves from hot to cold places in proportion to the difference in temperature. So in summer, your air conditioned house loses heat outward to the hot outside. Your house will get hot faster when its hotter outside. In the Winter, reverse the process. Insulation will work the same in either case.
Insulation slows heat transfer by impeding the three different way that heat moves (see heat transfer)
The most effective insulation is a vacuum. That is why we used to have "vaccuum thermos" containers before we came up with advanced closed cell foam that could be blown into shapes.
In a vaccuum, the heat cannot move by either convection or conduction.
The next most effective insulation is air. STILL air. If the air moves either through an area, then it is transferring the heat by convection, like in your oven. Air gaps that are too large can have "convection currents" that go in a loop to carry the heat from a cooler window pane to a hotter one. Or inside a wall gap. If there is a leak, then the air just carries the heat with it through the air gap. That is why leaks are so important to heat loss control.
So the goal is if you can't have a vacuum, to keep the air STILL. That is why double paned windows and foam and air barriers with fiberglass work better than single pane windows or fiberglass with no air barrier.
Fiberglass is used on engine air filters. Fiberglass does not stop air flow. So without an air barrier, fiberglass is nearly worthless, only slowing the heat loss slightly.
Closed cell foam works by trapping cells of air. Open cell foam also traps some air, but not as much. Styrofoam encapsulates tiny tiny air bubbles in plastic.
Storm windows work by slowing or stopping air flow.
Cellular shades work by trapping a cell of air.
Exterior insulation works by trapping air outside stone and mortar so the air inside can use the stone as a "thermal battery" and store heat.
Eventually entropy wins and everything ends up the same temperature. Insulation only slows that process down.
Also interior storms can be constructed for rental historic office or residences cheaply enough to save more than what was spent on the storm windows. There are also more permanently attached magnetic interior storm windows.
Interior storm windows stop the air leakage that accounts for MOST of the lost heating or air conditioning. Then shade cloth in the summer prevents too much radiant heat from the sun coming in.
Cellular shades can insulate the windows from conducted heat lost in both winter (nighttime) and the summer (daytime).
Generally interior storm windows are made on a wooden frame sized to the window minus about 1/8th of an inch. Then weatherstripping is applied to the outside after PolyOlefin ("heat shrink") film is wrapped around that frame. That weatherstripping provides both the air seal and the friction to keep the interior storm window in place.
Commonwealth Solar can manufacture interior storm windows.
There are several issues that can be addressed to make lighting more beautiful and efficient
There are many common misconceptions and occasionally misinformation that will waste your money and give you very little to no comfort increase for the dollar.
Once you understand some basics, you can see where a trained energy detective auditor can make a huge difference for much less investment.
Here's just a selection of four examples:
Example 1: Fiberglass insulation. Air filters are often made of fiberglass. You can often SEE where a leak of air has passed THROUGH the fiberglass insulation by the dirt that it has filtered out of the passing air.
Fiberglass insulation only works when there is no air flow or air pressure. Typically an air barrier of some kind ensures no airflow so that the insulation can work.
Dusty dirty fiberglass tells you that either
no air barrier was installed,
or was badly installed,
or has failed.
Using blown celluloses insulation instead of rolls of ineffective fiberglass does a much better job of filling in gaps and stopping air flow.
Commonwealth Solar provides the service of blowing cellulose insulation and simultaneously sealing your attic and walls after a proper audit
For more information on controlling air flow with insulation and vapor barriers see Building Science.com.
Example 2: Misconception: Radiators are inefficient. A radiator will lose the most heat to whatever is closest and coldest. Heat goes from a hot place to a cold place.
So what is the coldest place that is closest to your radiators?
The wall of course!
So by placing pennies worth of reflective foam insulation behind your radiator you dramatically lessen the lost heat to that cold exterior wall!
Example 3: Solar Attic Fans. An attic stays hot long after the sun goes down. Also the purpose of ventilation is to remove moisture (if there is any) as well. A solar activated fan typically does NOT have any moisture sensor.
Far better to
There are many other misconceptions for which there are tricks of the trade.
Call Commonwealth Solar to have an energy detective find your energy thieves and help you spend the money you already use for energy much more effectively!
A house needs to stay DRY to prevent rotting, rusting and mold that harms you and the house.
Moisture can come from uncovered earth beneath the house in the crawl space or through untreated concrete in a basement or leaks from above in the roof or walls or window frames or from plumbing or improperly plumbed equipment such as the air conditioner handler.
Moisture is mostly carried on air currents. That's why kitchens and bathrooms come with powered vents to remove excess moisture after bathing and cooking.
So by stopping air flow with proper air sealing and insulation to prevent condensation is the most effective way to prevent transfer of moisture.
Moisture above 49% humidity can cause ubiquitous mold spores to grow and damage wood and in some cases, people's lungs etc.
You can never "eliminate" mold. Mold is ubiquitous in nature and is ever-present.
You can only control mold by denying the spores access to moisture or organic materials that give a great base to grow on.
One way to control mold during a building upgrade is to use "paperless sheetrock" that uses fiberglass matting instead of paper to contain the gypsum. While plaster itself is not very friendly to mold, the wooden lathwork that is typically used with plaster is VERY mold friendly.
For more detailed information on moisture and its control visit Building Science.com
Building Science literally wrote the Department of Energy books on moisture control and "sick building syndrome".
Brittle Power: Energy Strategy for National Security (pdf) in 1982 .
The idea is that for several reasons, a saved watt can be more effective than another watt of produced energy. Some selected reasons (not limited to) :
For example, careful placement of windows can allow the sun to heat your entire house even when there is snow on the ground!
While most passive solar features must be considered at the time of design for the building or addition, there are some features that can be retrofitted later.
For example, proper placement of appropriate trees can dramatically increase solar gain in the winter while reducing the solar impact in the summer.
Related to "Passive Solar" is the concept of "Passive Survivability" ...
Passive Survivability is an architectural concept that can make an "off the grid" or emergency backup energy system much more affordable as well as protect the occupants in emergencies.
One way to use Passive Survivability to make an emergency system more affortdable:
Another way an electrician might think of Passive Survivability when wiring up Solar PhotoVoltaic panels to provide electrical power from the sun is to talk in terms of a "Dedicated Loads Panel" that puts the solar power into a selection of the breakers for your house such as the microwave, refrigerator and water pump, lighting just for the halls, bathroom and kitchen.
This means you only power the vital functions making the system that much more cost-effective.
A wood burning stove can be an effective way to take the morning chill off without running up your electric bill with the heat pump.
Heat pumps are less efficient for heating as the outdoor temperature drops.
So since it is coldest in the morning just before the dawn, a pellet stove on a timer or as auxiliary heat on a smart programmable thermostat could kick on at 5am or so and warm the house at less cost than a heat pump. Then the heat pump could come on in the afternoon just before you get home to take that afternoon heat and sunlight and "charge" the house with extra warmth (say up to 70 degrees) for your return from work or school!
Farmers could support the electric grid by installing solar panels that will actually be the most efficient in the cool of a clear morning, but using pellet stoves to heat the bedroom and bathroom and sell that excess energy for lighting and the shower.
Pellet stoves can use a renewable Virginia resource to heat with very little electrical power (just for the fan and auger to move the pellets.)
Sealing a house against air leaks closes off many routes to moisture, food and shelter that pests need to survive.
One of the best ways to control cockroaches is to caulk the baseboards.
Termites like crickets must have ready access to lots of moisture. You can tell a house has a moisture issue by how large a cloud of crickets greets you in the crawl space or basement. Dont worry if a few hundred bounce off you, they don't bite. Crickets are just an indicator of far more insidiously damaging moisture problems.
Spiders like to eat flying insects so they set up their webs in the air flow.
Spiders are a hint that air may be leaking in or out behind that spider web.
And while a mouse can fit through anything their heads fit through, if you stop air molecules, its doubtful a mouse will get through either! Don't forget that mice will climb up the outside of a house and come down in through the attic! This is another reason that it is important to seal penetration points into the attic as well as insulate.
Programmable Thermostats help the most with heat pumps as opposed to electric strip, oil or gas fired furnaces or boilers. However, a good quality programmable thermostat can incorporate those features.
Since air leaks ensure that whatever air you heated or cooled 8 hours ago has long since leaked out and headed downwind of your house or up into the clouds ... a programmable thermostat cuts back the effort of your heat pump, furnace or Air Conditioner when you are not around.
A professional energy audit can help here.
Energy Star on Programmable Thermostats
Since a hot transfer coil in a forced-air heat ducted system needs at least 130 degrees F to 180 degrees F ... trying to use solar thermal panels for space heating is quite challenging.
Unless your space heating only needs 80 to 100 degrees F for the working fluid to transfer heat!
A radiant floor heat system that uses 80 degree to 100 degree water in tubes under your feet is easily achieved with solar thermal panels!
According to This Old House, for example, a radiant system can be up to 30 percent more efficient than forced-air heating, depending on how well insulated a house is.
Tool Base on Radiant Floor Heating .
Commonwealth Solar offices have floor heated by solar panels! Call to come by and see it in action! The floor will often be over 60 degrees F even when its below freezing outside.
Also consider that if we are lucky, we all eventually come to a point where we will live on a fixed income. Wouldn't it be good if the COST OF OUR FUEL WAS ALSO FIXED or even available?
Peak Oil will eventually mean that new easily accessible oil and natural gas will no longer be easily pumped out of the ground and that means that scarecity and high prices are guaranteed at some unknown time in the future. Since China and India are dramatically increasing their consumption of oil and natural gas, that is very likely sooner than later!
Don't forget that coal and uranium use oil in the extraction and transport processes.
And, after all, even if the US Government fell, you house will probably still be standing. And your building or house (unlike your 401k) was insured, right?
So while solar fuel is free, the equipment to collect, store and deliver it is not.
Conservation is very cost effective, though again, not free.
So what is the rate of return on investment on conservation and solar energy verses other investments, most of which are taxed ?
The US Department of
Energy estimates that over 5.6 million homes have been weatherized,
saving 30.5 million MBtu
of energy each year. DOE estimates weatherization returns $2.69 for
dollar spent on the program, realized in energy and non-energy
benefits. Families whose homes are weatherized are expected to save
$358 on their first year's utility bills.
Making the upgrades for Energy Star certification costs just 1 to 3 percent more but pays for itself immediately. According to Energy Star, Energy Star House upgrades (such as windows with reduced air leakage, properly sealed and insulated ductwork, insulated attics etc.)add just $10 to $15 per month to your mortgage payment but save you around $25 to $45 per month on your utility bills.
Commonwealth Solar Example:
If a $6000 solar thermal system was installed for a 4 person household:
Solar Thermal can typically reduce hot water electric (or gas) heating between 75% and 80%.
A typical household will use 20 gallons per person with a 70 degree rise in the hot water tank,
according to ASHREA (American Society of Heating, Refrigerating and Air-Conditioning Engineers) figures used for standards to plan by for Architects,
20 gallons per day in a 4 person household is 80 gallons a day.
70 degrees increse (from typical 50 degree cold water to 120 degree storage temp)
That is 46,648 btu / day for that household.
3413 btu/Kilowatt Hour
12 cents per KwHr (divide your electric bill including everything for what you REALLY pay!) Typically as of March 2009, most people find that by dividing their monthly total payment by the number of kilowatt hours used for that period, that they pay about 12 cents per KwHr.
13.6 KwHrs is $1.60 per day.
$584/ year for a regular electric resistive strip hot water heater.
And a typical two panel system for a family of four saves 80% off the resistive tank so that SAVES $467.20
So now apply that SIMPLIFIED Rate of Return formula:
$467.20 / $6000 * 100 = 7.786% Investment Rate of Return
NOT including fuel surcharge increases ! (energy inflation)
Keep in mind that China and India are dramatically increasing their energy usage ...
NOT including Tax Credits
NOT including SRECS (sends YOU money !)
Those last three items are moving targets and are hard to impossible to calculate!
So consider that almost 8% as GURANTEED MINIMUM by quite a long shot!
And its insured by your homeowner insurance. Was your 401K insured?
The system can last 30 years easily so ... what's that investment worth after 30 years?
That investment is the equivalent in $63,309 after 30 years when you have to rehab the system or install a new one. Sometimes they last longer! Commonwealth Solar has been installing systems since 1975 and many are still in operation!
ALSO ... that's $63,309 that was NOT TAXED!
That's an additional $63,309 that was not taxed that you can invest for retirement, use to go back to college, send your kids to college ... start a business.
The payments for an Energy Efficient Mortgage at some 7% or sometimes lower is way less than the savings from the energy efficiency investment. And then you pay it off and still keep the savings!
Speaking of keeping the savings - small savings can really get you out from under that mortgage a lot earlier! Freedom From Debt Much Sooner! In this example, if you saved $43/mo you could pay off your mortgage three years earlier.
And finally, what is the rate of return on safely reducing your utility bills many decades into the future when your income may be less than it is now? What is the investment value of Peace Of Mind and Freedom to live on less when you are older and living on a fixed income that may not be as high as you originally planned?
Its referred to as a "resistive strip" though often it is in a coil form.
In most heat pumps it is often called "auxiliary" heat or "emergency" heat. It is often kicked on when the thermostat is run up more than 2 degrees from the current temperature. So be careful what kind of thermostat you use and how it operates that resistive strip. Some heat pumps use gas or hot water as the backup in which case this does not apply.
The exception is when you need heat in short blasts for little capitol envestment and then save a lot of energy because the rest of the space is less or not heated.
An example would be a heater pad for your dog or feet where you sit so the dog or feet are heated directly and the rest of the house is left at 62 degrees. Another example is a radiant heater in a bathroom. You only heat your body directly as you come out of the shower with a focused parabolic shaped heater with the glowing strip in the center. That way you leave the air temperatures low during the other 23 hours and only heat your body as you exit the shower. Don't forget to put those on a temperature sensor (so a warm sunny day cuts off the foot warmer or dogwarmer) or timer or have the memory of an elephant.
Speaking of hot water, the most common place to find a resistive strip is in an electric hot water heater.
This is why anything you can do to reduce that heat use will save you relatively large amounts of money.
Insulate the pipes coming out of the tank (don't forget the emergency overpressure valve! Leave a little gap for the water to escape in emergency from that valve)
This is why thermal solar hot water is often a very cost effective investment and why for smaller households that use little hot water, a heat pump water heater is cost-effective. You also get a bonus of dehumidification and cooling of wherever that heat pump hot water heater is.
So watch out for any claims that so-and-so heater will save you money ... does it have any variation of a resistive strip? It might be more efficient if you only heat very small spaces for short periods of time - like the bathroom or the doghouse.
Proper sealing of a basement or crawl space should vent the radon.
reducing peak cooling time costs by 10 to 15% (Energy Star) to 40% (Heat Island Group) . Please note there is a recommended technique to applying this material correctly.
When choosing a coating Pay attention to the "emissivity" of the coating, shingles or membrane.
ALSO silver rarely allows the black staining from the mold and mildew that often grows on asphalt roof tiles. Thus it will likely actually look better than the bare roofing shingles.
And ALSO the Silver or White reflective roof coating will protect the roofing shingles and membranes so that you get much more lifespan out of the roof
And finally, whatever is in the attic (such as the air handler for the air-conditioning heat pump) will suffer less heat as well as the ductwork thus reducing your air-conditioning bill!
One of the Commonwealth Solar installers, Christopher Maxwell, put a TPO Energy Star reflective membrane on his 1906 downtown style brick urban row house with a with passive vented attic. The summer temperatures that occasionally hit 103 degrees F in the shade of a roadside tree correlated with about a 95 degree attic at the same time. The second floor was 92 and the first floor was 88 degrees F with no air conditioning at that time! It was possible to use that space for storage of most anything after applying the reflective roofing. Also not so bad to work in when needed
After 35 years of experience, we've had to go back and remove panels so a roof can have its shingles or membrane replaced. Now we put flashing on our panels and racks so that roofers can just replace the roof membranes and shingles around the panels without disturbing them. The panels protect the roof underneath them.
The flashing is also angled with a downward slope so that snow and leaves dont end up trapped on top and can fall away. This also helps preserve the roof.
Here's another reason we flash the solar panels:
Snow and leaves should not be allowed to get backed up behind the panel and rot the roof. This photo shows the installation on the Davis house before we added the flashing. The pipe is shown insulated all the way, of course. The flashing is installed with a slight positive slope so that leaves and snow don't back up behind a "dam" of flashing either and flows off for cleanup.
It can work wonders for your house or building just as well !
The sun coming in each of your plain windows can bring in almost as much heat as an electric space heater per window! So the shade cloth can really make life much calmer, cooler and easier on your air-conditioner and thus your sweaty armpits and wallet.
Commonwealth Solar can consult on and install all the various forms of window insulation and heat control including shade cloth.
Solar panels are like many sun-loving flowering plants, they MUST have DIRECT sun and the panels must FACE the sunlight in order to work well. Solar panels are also most effective when tilted at an angle (inclination) equal to the latitude on the Earth. In central Virginia that is about 37 or 38 degrees inclined from the ground (horizon).
Notice for example that few plants besides moss grown on walls? That's why.
Its amazing how many solar panels are placed or maintained without this consideration.
Shading affects photovoltaic (electricity generating) panels much more dramatically than solar thermal panels.
A solar thermal panel can have a small percentage of the panel shaded by, say, a large branch of a tree or corner of a chimney.
But solar photovoltaic (PV, the electicity generating cells) must have UNinturrupted solar along a "string" of panels.
An excellent example you are more likely to be experienced with are Christmas lights whose bulbs have been wired in series so that one bulb goes out and the entire string stops working.
Solar PV cells are the same way. When a panel is wired in series (as they almost always are since each cell only produces half a volt and we need from 48 to 120 or even 600 volts for a fully effective solar installation) with two or more panels, shade that is completely covering any ONE of those cells will inturrupt the electicity for the whole string. Now sometimes you will see a pair or more strings that are wired in parrallel. The shading only knocks out the one string that is shaded, cutting the power of that system by one third (in a three string system). But if that shade from a chimney or tree branch cuts one cell in EACH string completely, then the whole system is out.
So when considering location for solar, remember that for PV, no single one cell can be completely covered by shading or the whole panel and string attached to that panel are now out.
Again, Solar Thermal is not as affected, but shading is important to full performance there as well.
Watch your trees! They will grow. Check the species you have and what their mature height and spread will be. Trees near your house are good for cooling your house (use Gutter Helmets or similar to keep your rain gutters clear) so you might consider putting your solar panels on an "out building" like a tool shed or carport.
A typical window thus transfers almost as much heat as a typical 1500 watt space heaters!
Straight clear sun is over 300 btu. Clear glass is about 80% clear to sunlight.
A typical window 3x5 feet so that's 15 square feet = 3000 btu
1 KW is 3400 btus space heater is typically 5000 btu
So you want to use that gain to heat your home in the winter, and get rid of that heat in the summer with exterior shade cloth
Solar Renewable Energy Certificates (or
“Credits”) (SRECs) are
a commodity traded in the USA that represent 1 megawatt hour of energy
to the electrical grid using “Net Metering”.
You could get a
quarterly check for your installed solar generation system!
Sol Systems LLC, a commodity brokerage, states that their anticipated 5 year average SREC price is $350 on their Virginia Pricing web page. The value of the SREC is paid quarterly to the system owner after subtracting the brokerage fee.
SRECs came into existence when states implemented an RPS (Renewable Portfolio Standards) in response to citizen demand for stable, sustainable power that polluted less.
Many states near
1000kWh = 1 REC.
Volatility in the price of traditional
energy sources due to
both greater demand by
In contrast, the sun is a stable source of
cannot be manipulated by large corporate or political forces.
SRECs are a commodity whose price depends on supply and demand. The value is provided by an NCF or ACP set by the government body demanding that the utility providing power to their citizens meet the RPS. This creates a modicum of a guranteed market for stable investment. On the demand side, often companies or government agencies buy SRECs also sometimes known as “Green Tags”.
reports, “The Air Force is the
largest purchaser in the
Dominion sells an option to their
subscribers for renewably
produced energy at $2 per 133kwhrs.
Solar power on the other hand can be placed in any sunny space such as
your roof, as shading on a parking deck or the roof of a mall.
Solar power on the other hand can be placed in any sunny space such as
your roof, as shading on a parking deck or the roof of a mall.
SREC commodity trading is complicated by
dozens of states
with different RPSs and NCFs or ACPs so finding the spot value of an
be challenging. A further complication - states with voluntary RPS or
no enforced NCF or ACP. This complication explains the existence of
SRECs such as Sol Systems LLC. Commonwealth Solar LLC has negotiated a
with Sol Systems aiming for as realistic a balance to ensure working
possible at this time. For example, following consultation with
Commonwealth Solar LLC., Sol Systems has now added requirements to list
the equipment, model numbers and show that the system is not shaded as
a control against fraudulent system claims that may come about as the
shysters discover SRECs. This is one reason why Commonwealth Solar has
survived through the boom and bust cycles since 1976 - a real desire
for effective affordable solar energy in efficient buildings.
A further complication is that SOLAR
Certificates are made more valuable by different statutory provisions
different states. The method and amount differs by each state or even
sets the Renewable Portfolio Standard (or Feed In Tariff) for power
Another factor in the price of SRECs beyond a desire for energy prices as stable as the sun is the realization that pollution costs our citizens and economy and resulting demand for reduction of that pollution with (among other tactics) RPSs that push for creation of energy that cost us less by polluting far less.
From Wikipedia: (http://en.wikipedia.org/wiki/Photovoltaics )
‘Life-cycle analyses show that the energy intensity of typical solar photovoltaic technologies is rapidly evolving. In 2000 the energy payback time was estimated as 8 to 11 years, but more recent studies suggest that technological progress has reduced this to 1.5 to 3.5 years for crystalline silicon PV systems .’
A third factor (of many) in the price of SREC commodities is recent talk of a national RPS.
If the possible national PPS includes a reasonable mandatory NCF or ACP, then when combined with the difficulty utilities have in laying new large power lines, there will likely be an explosion in the demand for distributed power production that can be paid for with SRECs rather than centralized big utility grade systems.
Centralized utility grade alternative power out in the middle of unpopulated areas must be backfed hundreds of miles into the grid with huge power lines. In December 2008 CSA.org reported that a national RPS may allow double counting of your SREC depending on how it’s written.
RPS and SRECs can also help combat fraud and abuse of the upcoming boom in solar energy. Fraudulent and incompetently installed systems in the last boom/bust cycle trashed the solar industry for a generation harming most and only helping a few shysters.
The recent efforts toward Smart Grids could
require that all
systems that receive any public benefit funds or tax breaks be measured
The smart grid could both measure and report which systems really worked and which worked better so the buyers, regulators, installers and maintainers of solar systems would have motivation as well as a verification method to ensure a properly functioning system. Also even the best intentioned and installed system can have breakdowns and a constant means of measuring will provide alert and diagnostic functions.
In the meantime, it is becoming more likely
buying SRECs or brokering them will require some verification with a
meter attached to the solar system.
The web page on Virginia Pricing for SRECs
by Sol System LLC
shows a price for $350 per SREC as their anticipated 5 year average
broker pays quarterly minus their usual brokerage fee. This includes
the fact that
Sharing Capitol Ideas website:
(please note that SOLAR Renewable Energy Certificates are worth more than other energy sourced certificates.)
Sol Systems position on Carbon Trading vs Renewable Portfolio Standards
The summary: Carbon Capture of coal is vaporware and doesn’t exist – solar has existed now for many decades!
Dominion’s voluntary sale of “Green Power”
Some leading advocates of an RPS for
Energy And Security Group http://www.energyandsecurity.com/virginiarps.html
Energy Justice Network (critical of any RPS that allows dirty power to be counted) http://www.energyjustice.net/rps/
Wikipedia for more detailed information:
Later on we will have a spreadsheet showing the rate of return on investment you could expect based on certain assumptions with SRECs at different values. You then plug in whatever your information sources cause you to think they will be worth and inform your consideration accordingly.
The same thing happens in any box ... including your house!
That is why you feel a draft at the bottom of a door more than the top. And why the basement leaks are SO obvious when you find them. But you can't seem to feel any leaks on the top floor ceilings.
That is also why the windows in the middle make less difference (in still air) than air-sealing the basement, crawl space and attic.
That is also why air leaks and infiltration is the #1 cause of lost cooling and heating.
And also why open fireplaces are a major source of lost heat ... and why they often have glass doors in front of them.
One tip that this is rampant in your building is extra-dry air leading to chalking skin and nosebleeds.
Combustion of air in your living space is then exhausted along with the moisture and the cold air coming in is relatively dry thus dramatically drying out your living space air and causing dry skin and your nose.
TIP: CLOSE THE CHIMNEY DAMPER When its not in use!
"According to the Department of Energy, a lit fireplace sucks about 24,000 cubic feet of furnace-heated air up your chimney each hour.
Bonus: It's replaced by cold air that comes in the opposite direction through the same opening, causing your furnace to work extra hard to keep your house toasty.
Crack a window in the room where the fireplace is located and then close the door, so it doesn't suck too much warm air from the rest of the house.
TIP: Provide a "Fresh Air Vent" for your combustion devices (gas fired hot water heater, furnace, fireplace, etc.)
"Stagnation - when the pump ... does not run as intended during sunny conditions. With a closed-loop glycol system the HTF (Heat Transfer Fluid) is then left sitting in full sunshine in the solar collectors, without circulating. The fluids are heated to a point where the buffers in the e.g. an antifreeze solution are broken down, and the solution can become acidic. The pressure can build up so much that the pressure valve will open. This would safeguard the integrity of the collectors and the whole system. The antifreeze has to be changed after stagnation conditions.",Stagnation is most common when a system is put in that is either inappropriately placed (on a building or use that does not use its full capacity, especially in the hottest summer months!) or has not been maintained and doesn't pump appropriately.
page 203, Tom Lane, Solar Hot Water Systems: Lessons Learned 1977 to Today, Energy Conservation Services, 2004
Stagnation damaged systems can usually be repaired and placed back in service, but stagnation on a maintained system or recently installed system indicates that either the designer was not informed of the actual usage patterns that result after installation (misunderstandings or perhaps a change in usage pattern post installation, say, the house was foreclosed on) or was installed inappropriately perhaps for showboating to say "look how green I am" when it was an inappropriate usage.
For example, an innapropriate use for an antifreeze thermal system would be an office building with no significant hot water usage on, say, a school administration building whose staff is on vacation in August when the system needs to be used the most to reduce stagnation.
Recommendation in this example scenario of a school admin building would be to :
"Drain back" systems do not suffer damage from stagnation except under very rare circumstances because of a "high limit switch" that senses when the hot water storage tank has reached a high temperature limit of, say for example, 160 degrees F when any further heating could be dangerous or damaging to systems. The high limit switch turns off the system pumps and the water drains back (hence the name "drain back system") into the holding tanks. The panels are now empty except for air and stagnation is not a problem when drained.
Put another way, the thermal shell describes the part of the building that separates your occupied conditioned (heated or cooled) space from the outside. For example in the attic, your "roof" comes in TWO parts. The outside part that keeps out the water ... and the floor of the attic that separates the thermal areas. The attic is vented to the outside and the insulation airseals and insulates that from your top floor rooms.
Note that the thermal envelope is not always the same exact place as the weather (liquid) envelope.
In this picture, the orange parts are generally where you would place insulation.
An exception is that, if you can, by placing the insulation on the outside of the thermal mass (bricks) you can help make the house more efficient by using that thermal mass to even out the temperature swings. Thus your heater and Air Conditioner now works against your cliamates's AVERAGE temperature instead of that day's temperature.
Here's a link to a great example house ...
The idea is that the cost of a house is intimately tied to what it costs to heat and air condition that house. The payments for energy for an inefficient building can easily equal a car payment! Unlike cars whose many ten$ of thou$and$ of dollar$ are typically paid off in 5 year$ ... those high energy bill$ will continue to increase for many many decade$ !
Consider asking your elected representatives to bring back some variation on VaHERO or other Home Energy Rating System (HERS program) that ties the appraisal of a house during sale to an energy rating.
There are some pilot programs that may bring us back to a HERS program such as the proposal to Pilot Test a Home Performance with ENERGY STAR Contractor Partnership in December 2008
Virginia currently is NOT one of the states with a Home Performance with Energy Star program.
[more on VaHERO and HERS at Virginia Solar Energy Association]
RESNET and their belief in HERS to make mortgages more affordable through energy conservation.
But since air leaks are THE major way to lose heated and air conditioned air ... ASK HOW WELL DO THOSE WINDOWS SEAL OUT AIR FLOW ?
A good window will have FOUR ratings. The most often hidden or not mentioned rating for a window is how well it seals against wind and air leakage due to Stack Effect.
Bob Vila recommends you select windows with air leakage ratings of 0.3 cubic feet per minute or less.
leakage - air leakage can occur through and around
windows, and can have a significant impact on energy use and
comfort.Air leakage at existing windows may be improved through
weatherstripping and caulking. New windows are often tested for their
air leakage through the window (between frame and sash). Better
windows have tested air leakage rates between 0.01 and 0.06 cfm/ft of
perimeter. Casement, awning, and hopper type windows tend to have lower
air leakage rates than double hung or slider types due to the
compression of the seal when latched closed.
Another issue with windows is that the South facing windows should be clear with NO "low-e" coating. This is so that you can accept the sun's free warmth in the winter!
Go ahead and put low-e (emissivity) coating on the North, East and West windows since you will not gain much heat from the sun on those windows anyway.
Then properly manage the heat through your windows with :
Shade Cloth on the outside in the summer to bounce back the sun in August
Cell Shades to keep your heat in your building on winter evenings.
Dont forget to
air leakage rates !!!!) and of course air sealing on the upwind and downwind sides of the building.
on average, weatherization reduces heating bills by 32%."
If you have any further questions, please email and ask so that we know what we need to add to this appendix !please type manually the email address below into your email system.
Note: Last Update 04/01/2009
by webmaster Christopher Maxwell
CommonWealth Solar, LLC
12433 Autumn Sun Lane • Ashland VA, 23005 • (804) 798 537