Insulation
Insulation is installed in walls and ceilings to slow down the flow of heat between the interior and exterior of the house. “R-Value” is the term used to measure a material’s insulating value. The higher the “R”, the higher the resistance to heat, and therefore the better the insulation.
Common Insulation Types:
Consult this list to be sure that you are making the choice that makes sense for your home and your health.
Batts and blankets:
Fiberglass batts and blankets are the most common type of insulation in U.S. homes, but not necessarily the best. Batts are pre-cut, blankets come in a big roll. Cotton batts or “blue-jean insulation” – non-toxic alternatives to fiberglass – are also available. The advantages and disadvantages below refer specifically to fiberglass batts and blankets, by far the most common.
Advantages:
Fire resistant, won’t settle over time. Good for retrofitting an attic if there aren’t a lot of obstructions; just lay it on top of the existing insulation, taking care not to leave gaps or skimp out around the eaves. Fiberglass is inexpensive (compared to cotton batts, spray-foam or rigid insulation), and is comparable to cellulose in terms of R-value.
Disadvantages:
Can leave holes and gaps where air can circulate, reducing the R-value, or where condensation can occur, also reducing R-value. Fiberglass particles pose a health threat during installation. It takes around 10 times as much energy to produce fiberglass insulation as cellulose, so it’s not especially friendly to the environment. You wouldn’t be able to retrofit walls with batts without removing the drywall.
Loose-fill (cellulose insulation):
Can also be wet-sprayed (applied with a water-based adhesive).
Advantages:
Cellulose is made with up to 80% recycled material (shredded newspaper, mostly), it uses less energy than fiberglass to manufacture, it’s non-toxic, inexpensive, more effective than batts at sealing air leaks as well as nooks and crannies, flows around wall studs to increase the R-value of the entire wall, and it’s highly flame-retardant. It’s also easy to retrofit walls with dry-fill cellulose by cutting a small hole (which would be patched later) in between each stud at the top of the wall and blowing in the insulation. You’ll also want to remove a piece of drywall at the bottom of the wall to make sure the cellulose has made its way all the way down. Cellulose is also good for retrofitting attics; if it’s distributed evenly you can be sure there are no gaps in the thermal barrier.
Disadvantages:
May absorb moisture, and can settle over time if not installed properly, both of which reduce its R-value. It’s heavier than fiberglass, so it may cause ceilings to sag.
Spray-foam:
Advantages:
Foam expands, so it seals up leaks and gaps better than either cellulose or batts. It’s easy to install in tight spaces, and can be installed in wall cavities without removing the drywall. Spray-foam comes in all shapes, sizes, prices, and R-values. The two general categories are closed-cell and open-cell. Closed-cell foam has a higher R-value (about 6R per inch), but is more expensive than open-cell (which is about 3.5R per inch). For an equivalent R-value, open-cell will generally be less expensive. The high R-value-per-inch of closed-cell foam makes it a good choice if you have limited space; it also prevents moisture transmission better than just about any other insulating material.
Disadvantages:
Foam is pricier than most other insulating materials to begin with, and it will need to be installed by a spray-foam contractor (no do-it-yourself option), raising the price even more. It also releases greenhouse gases during application (HCFC’s or HFC’s), so it’s not the greenest option. Once installed, spray-foam is not a health hazard.
Reflective Insulation and Radiant Barriers:
Advantages:
Reflective insulation and radiant barriers serve primarily to reflect radiant heat, but do little to prevent heat transfer through convection. They’re highly useful in southern or warm climates where the main objective is to keep solar heat out of the building. They look like a big sheet of foil, and serve primarily to block solar heat, even though they’re applied internally. Here’s how: the sun heats the materials on a roof, for example. These materials, now hot, transfer heat through convection (heat moving through the material) and through radiation (heat emitted directly from material). The radiant barrier, which you could install by laying it on top of existing attic insulation, or by attaching it to the underside of the rafters, blocks the radiant heat, reflects it back into roofing material and keeps it out of your living space.
Disadvantages:
Doesn’t prevent convective heat transfer – so it won’t keep the heat inside in the winter. Reflective insulation does include a thin layer of material to prevent heat transfer through convection, and so has a small R-value (a radiant barrier has no R-value). Reflective insulation and radiant barriers thus serve as a supplement to bulk insulation (i.e. cellulose, spray-foam or fiberglass batts), but will not suffice on their own, particularly in cool climates.
Rigid Panel Insulation:
Advantages:
Rigid insulation has a high R-value per inch, so it’s a practical solution for a high R-value where space is limited.
Disadvantages:
They can’t be retrofitted into existing walls without removing the drywall, and are susceptible to the same air-leakage problems as fiberglass batts and blankets. They need to be meticulously installed to limit gaps and air leaks, and they’re slightly more expensive than alternatives.
There are many types of insulations to choose from and The Building Doctors can install them all.
For more information, call 323-646-2534 or email us at info@thebuildingdoctors.com
Renewable Energy
Renewable Energy is energy generated from natural sources such as sunlight, wind or geothermal heat, which are renewable or naturally replenished. In Southern California most residential and commercial applications are through sunlight though new applications are emerging for wind. The Building Doctors are big supporters of renewable energy. However, through our “Whole Home Performance Check Up” it is important to identify your waste then to reduce and conserve your energy use. Then we suggest to use solar or wind sources to balance out the remainder of your energy consumption.
Solar Power
Photovoltaics, commonly known as PV, converts the solar energy in sunlight into electrical energy with a system producing no air pollution and using almost no moving parts. They are extremely reliable with a 25 warrantee and a 40 year design life.
Solar modules, groupings of special silicon cells, produce a DC (direct current) electrical charge when the cells are struck by solar energy. The DC current is routed to a device called an inverter that changes it into the AC (alternating current) electricity required by most household and business applications.
The result is a clean and reliable energy alternative for either residential or commercial use. A PV system can be integrated into a new construction project or installed on an existing building. Typically, PV modules are mounted on a building’s roof but they can also be mounted on the ground, on a nearby roof, or even incorporated into a shade structure.
PV systems used to power buildings fall into four basic categories:
“Grid-Tied” or Grid-interconnected PV systems are the most popular and use special inverters to allow electricity to flow safely back into the electric grid. When solar power is generated, surplus electricity can actually flow back into the grid after the power for the building is used. Depending on your utility company, you will be given full retail credit per kilowatt-hour. Since there are no batteries, these systems cannot store energy and are designed to shut down if the grid is down for safety reasons (mainly to protect utility line workers).
“Grid-Tied” or Grid-Interconnected with Battery Back-up systems offer customers continued power when the grid goes down, while still being connected to the grid for seamless power. Newer systems also accept other power sources, in addition to PV, such as wind or even traditional gas-powered generators to provide power and/or charge the battery at night and/or if the grid is not available.
“Off-Grid” PV systems are used when a completely independent or “stand alone” system is needed. Since no grid power is used, the system must be carefully designed based on power usage, peak demand and seasonal solar variations. Batteries are typically used to provide power at night, in low sun or high electric demand conditions. These systems are ideal for remote locations where no utilities exist.
Utility-Scale PV systems, sometimes called “solar farms” provide power for regional users by (or in cooperation) with electric utility providers.
Regardless of PV system or metering, most homeowners should install a solar hot water system along with the PV system. Why both? Because a solar hot water system is significantly more cost-effective and requires a fraction of the roof space to create the equivalent amount of energy to heat water. This will also allow the PV system to satisfy a higher proportion of household electric demand, making the PV system even more cost-effective.
Take advantage of generous solar financial incentives – Two sources combine to help you pay for your house’s photovoltaic solar system. The federal government gives a one time tax credit equal to 30% of the total cost of the system. There is also a rebate from your utility provider that can be as high as $1,550 per installed kilowatt!
Solar Thermal (Hot Water)
A Solar Hot Water (or “Solar Thermal”) system can provide as much as 70-80% of your hot water needs for the year, greatly reducing the portion of your utility bill that relates to water heating, usually natural gas. If the water heater is electric, the money saved is even greater. A full-size system will typically provide all the hot water needed between March and October.
Although the basic technology has been around for a number of years, recent improvements make today’s solar hot water systems more efficient, reliable, and durable than those of the past.
A typical domestic solar hot water system uses two 4′ x 8′ flat plate “collectors” which are installed on the rooftop of a home or business (but can be located on the ground). These flow to a hot water heater, which is to be used as a storage tank and for back-up heat during the cold months of the year.
General Types of Systems
Hot Water systems are of two general types.
The first, potable water is passied through tubes and heated by the sun before flowing into the storage and heating unit.
The second type, non-toxic glycol circulates through the tubes, heated by the sun, and flows to a heat exchanger where it heats the water. A back-up heater provides any additional heating of the water.
Spa systems and pool systems function in a similar manner.
System Sizing
Domestic Hot Water – Generally, domestic hot water systems are sized according to the number of people in your family. Typically, two 4 ft. x 8 ft. collectors and a 120 gallon storage tank is sufficient for two adults.
Swimming Pool – Pool Systems require that solar collectors have a combined surface area equal to 50 – 70% of the pool surface area, with “glazed” type collectors being the most efficient.
A solar system for your home may not be as expensive as you think – The ever diminishing cost of technology, coupled with the generous financial incentives have made solar the most affordable its ever been. While a system that completely eliminates your entire electrical bill is ideal, a partial system can offer nearly the same savings but at a fraction of the cost. No matter what type of system you want, The Building Doctors can answer any questions you may have and install any system you prefer.
Wind Power
Wind power in Southern California is a very reliable a powerful source of renewable energy and extremely cost effective on a large scale. Residential and commercial equipment are starting to emerge. Please contact us if you have any questions or interest in wind power.
For more information, call 323-646-2534 or email us at info@thebuildingdoctors.com
Moisture Control
Since 60% of the air you breath in your home comes from your crawl space, when your windows are closed, it is important to address any moisture or odor problems. The installation of a vapor barrier which is a 6 mil plastic sheet placed on the ground of the crawl space helps controls moisture and odors issues.
For more information, call 323-646-2534 or email us at info@thebuildingdoctors.com
Lighting Retrofits
According to the California Energy Commission, lighting is estimated to be 22% of a homes electric bill. There are many things that can be done to deduce this amount including: daylighting; timers & sensors; and lighting retrofits. A lighting retrofit replaces the components that house incandescent bulbs to more efficient bulbs. There are two type of energy efficient bulbs currently on the market.
Compact fluorescent bulbs (CFL’s) are designed to be three to four times more energy efficient and last eight to ten times longer than an incandescent bulb. They come in many sizes, watts, and are now dimmable.
LED’s (light emitting diodes) use semi-conducting materials to convert electricity into light and produce more light and use less electricity. CFL’s last anywhere from 8,000 to 10,000 hours while LED’s can last 35,00 to 50,000 hours. They are just now making a slow entrance into the residential market.
The Building Doctors can retrofit your current lights including can ceiling lights for energy efficient, Title 24, approved lights. Energy bill savings from lighting retrofits pay for your new equipment quickly and actually produce a return on your investment.
For more information, call 323-646-2534 or email us at info@thebuildingdoctors.com
Building Envelope Sealing
Air sealing the building envelope is one of the most critical features of an energy efficient home. The blower Door test combined with a smoke test and Infrared camera imaging from our “Whole Home Performance Check Up” will determine how leaky or tight your house is. Leaky areas will be detected that need to be sealed that control air infiltration. This will increase energy efficiency, lower utility bills, and increase indoor air quality. Notorious spots for leaks in the building envelope are: attic hatches, recessed lights, gaps around doors, and windows, crawls spaces, and electric outlets. The Building Doctors are experts at locating and sealing these trouble spots. We use everything from caulk, expanding foam, weatherstripping, gaskets, and door sweeps to seal these air infiltration points.
For more information, call 323-646-2534 or email us at info@thebuildingdoctors.com
Heating & Air Conditioning
Air Conditioning and Heating
The Building Doctors specializes in the design and installation of the most current energy efficient heating, cooling, and ventilation equipment. The determining factors when installing highly efficiency mechanical equipment overall system efficiency are consistently sizing the unit and ensuring that the distribution system is secure. All of our systems designs are done in accordance to ACCA guidelines for system sizing and load calculations (Manual J), equipment selection (Manual S), duct sizing and design (Manual D), and air distribution dynamics (Manual T). After the installations are completed we performance test the entire system to make sure the air flow is correct and the components were installed properly.
Air Conditioning
Are you building a new home and deciding on air conditioning? Are you thinking of installing air conditioning in your current home? There are several pitfalls you should know about that can reduce the efficiency of even the best units by half, resulting in warm, humid spots and in higher bills than necessary.
The first problem to guard against is oversizing an air conditioner. On first thought, this would seem like a good idea – how can you have too much cold! There are three reasons:
First is that an air conditioner is most efficient when it has been running a while. If it is too big, it will run for a couple of minutes at a shot, whereas, if it is the right size, it will run much longer – on the hottest afternoons of the year, it should run all the time. This delivers the cold at the lowest cost.
The second is that the air conditioner is also a dehumidifier. Here on the West Coast we spend about 20% of our air conditioning money on taking moisture out of the air. If the unit is too big and spends more time off than on, the coils won’t get cold enough long enough to condense enough moisture.
The third problem with oversizing the air conditioner is that if you buy too big a unit, you are wasting money. A properly sized unit has a fudge factor built-in, so that once a proper heat loss/gain calculation has been done buying a bigger unit than called for is unnecessary.
In addition to oversizing the unit, there are other factors that can spoil an installation.
You can’t have a high efficiency system with low efficiency ducts. Ducts that run outside the thermal envelope, in attics and crawlspaces, typically have R-5 insulation installed. Compare this with your R-13 walls and R-30 attics! Any ducts that run in unconditioned spaces should be sealed tight and insulated to at least the level of the surrounding areas – R-40 would be desirable. It would be best to keep those ducts out of these unconditioned spaces to begin with.
The location of the air handler is also very critical. If the air conditioner is trying to make 55° air, but the air handler is in a 130° attic, then there will big reductions in the temperature that finally makes it into the house. Keep those air handlers out of attics and crawlspaces!
If ducts are in unconditioned spaces, duct leakage can introduce hot, humid air to the system if it is on the return side. Supply side leakage just blows expensive cold air to the outside. So sealing these duct systems as tight as possible is a very good idea. This is another reason to try to keep the ducts out of unconditioned spaces to begin with.
Cold air is harder to push to the second floor than warm air is. This is why so many houses that heat properly have uncomfortable second floors in the summer. There are a couple of low cost duct modifications that you make to be sure that the right amount of air is making it upstairs.
Just as in winter when house air leakage brings in cold dry air from the outdoors, in summer that air leakage brings in hot, humid air. This causes the unit to work harder and longer, and if this leakage has not been properly accounted for in design, it can cause great discomfort. In a very leaky home, you will be able to buy a smaller unit if you properly seal and measure the home.
Remember that the only way to get a “right sized” air conditioner is to have your installer complete a heat loss calculation on your home. In addition, an air infiltration measurement will allow him to avoid using the default rates, and therefore perhaps offer you a smaller unit. You can see how important it is to consider all aspects of your air conditioner installations. If you are installing new systems or replacing existing units, call us for details on these low-cost, no-cost considerations.
High Efficiency Furnaces
We install condensing gas furnace models with the highest efficiency ratings (90% AFUE or greater). Instead of a constant pilot, many models include a hot surface igniter and a microprocessor that automatically adjusts furnace output and blower speed for optimum efficiency based on thermostat information. These variable speed systems not only save natural gas but also dramatically cut electrical consumption.
Combined Hydronic Systems
In many situations, it is possible to combine domestic hot water production with heating and eliminate the furnace altogether. A hot water coil within the air handler of a Combined Hydronic System allows for heat exchange while the blower pushes conditioned air into a ducted system. These systems are ideal for small load applications and can be paired with tankless systems, solar thermal arrays, or a standard storage hot water tank.
For more information, call 323-646-2534 or email us at info@thebuildingdoctors.com
Energy Efficient Appliances
We have more appliances in our homes than ever before. Kitchen appliances alone can account for over 25% of total household electrical use. Appliance manufacturers continue to research and develop more energy or gas efficient models. With the savings from your utility bill, It may be cheaper to replace and extremely inefficient appliance with an efficient model.
If you need to replace your appliances, at a minimum standard, Energy Star qualified appliances should be considered. EnergyStar qualified freezers, refrigerators, dishwashers, clothes washers, and air conditioners use 10-50% less water and electricity than standard models. Please remember, there will be appliances that far surpass the requirements and some that just barely qualify.
To make a more informed decision, pay particular attention to the yellow EnergyGuide label, required by the Federal Trade Commission on all refrigerators, freezers, and dishwashers. It will provide estimated annual energy consumption, and estimated annual energy costs. That’s very valuable information to weigh against the upfront cost of the unit.
And remember, when you upgrade that old appliance, don’t throw it away, recycle it.
Here are some tips that will help reduce your utility bills no matter the age or efficiency of the appliance:
• Run full loads in clothes washers, dryers, and dishwashers
• Wash clothes in cold water: Modern detergents and washers will get them just as clean.
• Clean the dryer lint filter between loads, it’ll “breathe” easier and dry faster.
• Use a solar clothes dryer: You know, a clothesline. A little fresh air will do your clothes good.
• Eliminate the dishwasher heated-dry cycle: Why waste energy? Air-dry them for free.
• Clean refrigerator coils every six months: A little work, but big results.
• Keep your refrigerator and freezer full: If you have empty space, fill it up with jugs of water. It will operate much more efficiently.
• Eliminate that second refrigerator: A refrigerator can be the biggest energy-using appliance in the home, an old one even worse. Do you really need it?
For more information, call 323-646-2534 or email us at info@thebuildingdoctors.com
Duct Sealing
Ductwork Basics
Ducts are a critical part of your heating and cooling delivery system, yet they are given very little emphasis during construction. We encounter many systems with 92% efficient furnaces and 50% efficient duct systems. In order to have a duct system that performs properly, there are a few do’s and don’ts that must be understood:
Duct Sizing:
In order to arrive at the proper duct size, a heat loss calculation must be done on every house, or every model in a development. In addition, every “problem room” must have its own calculation done to ensure proper delivery. Problem rooms would include rooms, especially bathrooms, over garages, Cape Cod style knee wall rooms, rooms with high ceilings, rooms built over a vented crawlspace, or any room configuration that could result in high exposure to the elements. It doesn’t hurt to slightly oversize ducts to problem areas.
Duct Location:
The ductwork carries the hottest air in the house in the winter, and the coldest air in the house in the summer. In other words, these ducts carry the most expensive air in the house. We typically insulate our attics to R-30 to protect our 70-75° house from a hot or cold attic. However, we only insulate attic ducts to R-6 to protect the most expensive air in the house from these same attic temperatures. The best solution to this problem is to keep the ducts out of the attic, but if a short attic run is essential, this run should be low on the attic floor, between two joists, with R-30 insulation installed over the duct after sealing all joints and seams with a high quality sealant.
The heating/cooling unit itself is very lightly insulated, and leaks a lot of air. These units should definitely be inside the house.
Remember that a basement is a semi-conditioned space, and that it rarely will drop below 62-64°. If you need two systems in a large house, then consider putting both systems in the basement, one heating the left half of the house and the other heating the right half of the house. If you have to put a system in the upper half of the house, consider putting the unit in a closet to minimize exposure to the attic, and then putting a minimum of ductwork in the attic.
In situations where ductwork must be located in an exterior cavity such as the ceiling of a garage or an exterior wall, the duct should be rectangular or oval, and should make physical contact with the interior, heated surface. This way the maximum amount of insulation can be installed on the cold side of the duct keeping it as warm as possible (this same technique is best for water pipes to prevent freezing). Be aware of energy codes when insulating these cavities.
Remember also that returns are an important part of the ductwork and that the temperature of the return air influences the temperature of the supply air. With this in mind, be sure that no returns are run through an attic without being thoroughly sealed and heavily insulated, and that no returns are run through a garage ceiling or exterior wall without allowing for space for insulation, again keeping the appropriate energy codes in mind. Best to keep them inside!
Duct Leakage:
Ductwork is designed to deliver air from one location to another. If supplies or returns are leaking, then this air is not going where it is intended to go. With this in mind, there are areas of ductwork that must be sealed to prevent waste of conditioned air.
Returns should be sealed from the grill to the air handler. Every degree that the return air temperature drops due to outside air being sucked in is a corresponding degree that the supply air drops, potentially causing comfort complaints and high bill problems. Problems here can range from small cracks to missing headers.
Ductwork in attics should be sealed as airtight as possible using high grade sealants – you don’t want your sealant to fail after a couple of years. All ductwork that runs through an unconditioned space should be sealed with high quality sealant before insulation is installed.
Many supply ducts are installed inside the heated shell, and leaked supply air is contained inside of a properly sealed house. However, the larger potential leakage points should be sealed to get the air to go where you want it to.
We have seen 50 year old houses with well designed duct systems, and brand new houses with ones that are poorly designed. If you are building a new home, the changes needed are generally inexpensive and very worthwhile. If you have an older home, problems are a bit harder to solve, but solutions are still possible.
The Building Doctors only use low VOC (Volatile Organic Compound) mastic to seal your duct system and we perform a duct leakage test before and after our work so we can show you the amount of improvement we achieved.
For more information, call 323-646-2534 or email us at info@thebuildingdoctors.com
Water Conservation
1. Overview
For us humans, fresh water is probably the most important single thing on the planet. Yet close to 900 million people worldwide don’t have enough, and 36 U.S. states are currently facing a shortage. Southern California is currently under drought conditions. 50% of the energy Los Angeles consumes is used to pump water from northern California.
The good news is: every little bit helps, and it’s pretty easy to cut back on your water usage. The even better news is this: the average household spends $400-600 on water-heating, which is in addition to about $300 on water bills. Cut back on hot water and you can kill two birds with one stone. Water heating is the second largest consumer of energy in the American household (averaging 13% of household energy consumption), second only to space heating and cooling (49% of household consumption). There are some easy ways to reduce your consumption without giving your hot water system a total overhaul, and without sacrificing modern conveniences.
2. The Basics
It’s a great idea to minimize water usage overall as much as possible, but important to bear in mind that in the case of hot water, energy savings go hand in hand with water conservation. So if it’s high utility bills you’re concerned about, it’s most economical to focus on reducing hot water consumption. That holds true even if savings in gallons might not be gigantic, because, over time, the kilowatt-hours, dollars and cents you save will add up.
You can reduce hot water consumption by using a new, energy efficient dishwasher which uses about 1/6 the water as washing dishes by hand, washing clothes on the “cold” setting in a front-load or efficient top-load washing machine, and by installing a low-flow shower head and aerators for your faucets.
That said, the average American uses about 100 gallons of water daily. At about 5 gallons per flush, 20 per shower, 5-10 per minute watering the lawn, 15 gallons used in bathroom and kitchen faucets per person per day, and maybe a half-gallon ingested, it all adds up pretty quickly.
Of that 100 gallons – per person, per day, remember – about 70% is used indoors.
Some of this water use can’t be helped. You should, of course, drink plenty of water, and it’s much more efficient to drink it out of the tap than from a bottle (it can take as much as 7 gallons of water to produce one bottle, and up to 2,000x the amount of energy to produce a bottle of water as the same amount of tap water). But 26.7% (about 19 gallons) of our indoor water – good, clean, drinking water – being flushed down toilets?
3. Taking It On
So step one: if it’s yellow let it mellow. Step two, make a couple of other pretty easy adjustments to reduce wasteful spending of water and energy. These could be anything from fixing a leaky toilet, to insulating your water heater and pipes, to making an upgrade to efficient appliances and fixtures – dual-flush toilets, an efficient clothes-washer and dishwasher, low-flow shower heads, aerators for your faucets.
Old toilets, for example, might use 4-5 gallons per flush, compared to 1.5-2 gallons for efficient new toilets. Efficient, front-load clothes washers use only about 23 gallons per load, compared to about 41 gallons for traditional washers. A shower with a traditional shower head might run at 4 gallons per minute or more, while the newest low-flow shower heads can use as little as 1.5. Whatever steps you choose to take, be sure that minor adjustments can have a major impact on the global water supply, the health of our environment, and your wallet.
The Building Doctors can test each of your fixtures to determine their flow rate and we can make recommendations from there.
For more information, call 323-646-2534 or email us at info@thebuildingdoctors.com
New Windows
There are many questions that come to mind when thinking about replacing your windows. Will they help reduce noise and drafts of both hot and cold air, lower my utility bills, and will they be easier to open? Will they really be worth the investment? We’d like to help you answer these important questions and more. Please look at the information below to find out how professionally installed, new, high-quality replacement windows will bring you the comfort, efficiency, beauty, and return on investment you’re looking for.
A guide to shopping for windows
Single pane windows can account for 30% of the total heat loss during the winter and as much as 70% of the heat gain in the summer. It has been proven conclusively, with laboratory tests, that “Low E” glass has up to an 80% reduction in the heat that passes through it. The FTC (Federal Trade Commission) requires that any specific claims, as to how much money you will save by having double pane windows installed, must be validated with a comprehensive “energy audit” of your home. The Building Doctors “Whole Home Performance Check Up” will determine the return on investment and how much savings you will have on your utility bills.
There are many determining factors and everyone’s situation is different. What are the condition of your windows? Are you opening up your walls for insulation? Are planning on selling your home anytime soon?
If you decide to put in new windows use this information to help select New Windows for Your Home
Windows, doors, and skylights qualifying for the ENERGY STAR label must meet requirements tailored for the country’s four broad climate regions: northern, north-central, south-central, and southern. All of California falls under the south-central classification. ENERGY STAR windows must carry the National Fenestration Rating Council (NFRC) label, allowing comparisons of ENERGY STAR-qualified products on specific performance characteristics.
Map of ENERGY STAR window classes. From www.energystar.gov
U-value.
U-factor measures how well a product prevents heat from escaping. It is the inverse of R-value, which is familiar to many people as a measure of insulation thermal performance. The lower the U-value rating, the better the overall insulating value of the window. Typical U-values range from 0.20 to 1.20. The U-factor ratings listed on NFRC labels (and in the NFRC Certified Products Directory) take into account heat loss through the glass, window edge, and window frame.
Solar heat gain coefficient (SHGC).
The SHGC describes how much solar energy is transmitted through a window. Solar heat gain can be beneficial—providing free passive solar heat during the winter months — or it can be a problem, resulting in overheating during the summer. Windows with high coefficients are designed for colder climates, while windows with low coefficients are designed for hotter climates.
Visible light transmittance.
While SHGC describes the relative amount of solar energy that can pass through a window, the visible light transmittance is simply the relative amount of sunlight that can pass through, measured on a scale between 0 and 1. The higher the number, the greater the amount of light that can pass through.
Air leakage.
Air leakage is already listed by many window manufacturers, in terms of cubic feet of air per minute per foot of crack. An optional air leakage value is included on NFRC labels and in the NFRC Certified Products Directory.
Condensation resistance.
Finally, the ability of a window to resist the formation of condensation on the interior surface is very important in evaluating the relative durability of a window. The NFRC measures condensation resistance on a 0–100 scale. The higher the rating, the better that product is at resisting condensation formation. This rating is optional for new products.
For more information, call 323-646-2534 or email us at info@thebuildingdoctors.com