FAQ

The following is a brief FAQ of the most common green building topics.

Energy

Insulation
Tight houses
Windows
Appliances
Lighting
Heating systems/fuel
Passive solar
Solar hot water
Solar electric
On-demand hot water
Hydronic (radiant) heat

Health

Ventilation
Off-gassing/Toxins

Materials

Roofing
Siding
Construction lumber
Flooring
Finish lumber
Countertops
Cabinets
Salvage materials/antiques

Site/Water

Plumbing
Rainwater
Landscape

Design

Just the right size
Layout

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Insulation
Its is far more cost effective to insulate than any other energy saving strategy, and contrary to conventional wisdom, a large amount of insulation does make sense (the only case it doesn't is if you use lousy windows or have a lot of air leakage, but you're not going to do either of those, are you!). Think in terms of R30(walls/floor) and R40(ceiling) as being the MINIMUM reasonable amount for most climates. In reality, you probably ought to shoot for R50 everywhere when looking toward the future where fossil fuel energy is expensive. If the only way to get it, is to use petrochemical foam insulation, go ahead an use it: you still emit less greenhouse gases and still use less energy.

The limitation is fitting it all in, and to get to the high levels some thought is required. Walls ought to be double 2x4s, 2x6 sheathed in foam board or equivalent; floors and ceilings need 12" TGIs or the equivalent.

If you have a limited budget for green, this is the place to spend your cash. It is the single most important thing you can do. You'll get comfort and somewhat lower energy bills right away, and then 20 years (or whatever) you'll still be able to afford to heat it.

Read more about keeping heat in here, or about energy in general here.

Tight houses
By now most people have heard that tight houses can cause "sick building syndrome", and while that is certainly to be avoided, making a house "leaky" isn't a good solution. The problem is that on a blustery winter day the house will leak like crazy and on a calm spring day when the humidity in the house is more likely to cause mold problems, the house won't hardly leak at all. The best solution is to use spot ventilation to remove excess moisture caused by cooking and bathing, and a whole house ventilation system for more widespread moisture or toxics issues. The only really effective solution to toxics is to not bring them into the house in the first place.

Tight houses save a significant amount energy, and still provide a reasonable base amount of ventilation during much of the year. The energy used for mechanical ventilation is much less than the energy lost in a leaky house (at least it ought to be!). Keep in mind that the common measure of "tightness" is "air changes per house", which is how many times the entire air in the house leaks out per hour. A lousy house is around 1, and a tight house is around .15 (meaning it takes about 6 hours to replace all the air in the house). While this definition of tight certainly leaks less air than houses of the past, its clearly not that tight, considering that even a child's balloon will take a couple of days to lose all its air.

Read more about hot water here.

Solar Electric
Photovoltaic (PV) or solar electric is the one source of renewable electric generation that is available to most urban dwellers--all you need is a sunny spot to put up the panels and a way to run a wire to feed the power back into your service panel. Keep in mind that a small amount of shading will reduce your output as much as a lot of shading, so look for locations that aren't in the shadow of trees, buildings or other obstructions. At current prices ($6-7/peak watt in 2007), it tends to be only financially practical in areas that have expensive electric and/or some kind of rebate. Systems with battery backup suffer 10% (or more) efficiency losses keeping the batteries charged, but without batteries you have no power when the grid is down, even if the sun is shining.

The price of PV has been sinking regularly until 2005, and it is currently predicted that this will continue when the current shortage of silicon ends around 2009. For those who can afford PV, buying a system helps support the industry, which is doing much of the research funding. While is may not be cost effective, neither are a lot of other things most people own--beside its an easy way to reduce your carbon footprint once you've done all the more cost effective things (insulation, new appliances etc).

Read more about solar energy (including solar electric) here.

On-demand (Tankless) Hot water
Tankless hot water has been a popular (and in my view very over hyped) product, although conceptually a good idea. The idea of avoiding "standby losses" (the heat that escapes from the tank), is a good one, but not as simple as it would seem. What your actual loss is depends on your climate, and whether the tank is inside the house or not. Complicating it further is that the standby loss is less significant if you use a lot of hot water and if you have a pilot light. Then there are technical issues, like the fact that you might need a bigger gas line (or if you go electric, a bigger panel), and that the gas models don't work especially well with solar pre-heated water. Another consideration is that if you use any gas heater, you're using fossil fuels, while electric might be renewable, depending on where you live (on average 70% of the US electric supply is fossil fuel).

Before I get accused of bashing tankless heaters, let me state again that I think they are a great IDEA. The actual savings you get is less clear--depending on all the above factors.

Assuming you're trying to be as sustainable as possible, the biggest impact you can have (without changing use habits) is to install solar hot water. Depending on your situation, an on-demand heater might save significant energy.

For a complete discussion on hot water options, click here.

Hydronic (radiant) Heat
The hydronic heat industry makes a lot of claims about energy savings that I'm pretty convinced are false, but it is still probably the best choice, especially for super-insulated homes. The problem with forced air heat is that air holds very little heat, so you have to move a lot of it and/or make it quiet hot to heat the house. When you do make it hot, some of the dust ends up getting 'cooked' creating potentially toxic byproducts (it isn't clear how much of a problem this is, other than a tight house clearly makes is worse). The alternative, the hydronic fan-coil, heats the house very slowly and uses a significant amount of electric moving air while its at it.

Hydronic heat uses a pump to move hot water either thru piping in the floor (the most common) or to some kind of radiator in the room. Radiators transfer heat the best, but take up wall space. Hydronic heat can be driven off a boiler, hot water heater, or tankless heater, although most hot water heaters won't deliver enough heat unless the house requires very little heat. If the heat source uses a tank, then a low temperature system will result in lower standby losses than a higher one (for more on standby losses, see the tankless discussion)--and this is generally only an option for well insulated homes. Of course, the tank could be located inside the heated space, and turned off when heat isn't needed, but often the tank is used for both heat and hot water so this isn't an option.

The claim that radiant heat (the in-floor kind) saves energy is based on the assumption that the floor is warm and that as a result people will lower the thermostat (since much of your perception of warmth is based on floor temp). However, in a super insulated home, the floor will not be that warm because it doesn't need much heat, and further at least one study found that people didn't turn the thermostat down at all. The reality is that climate, insulation and air infiltration are the major factors governing energy use.

There is a claim that radiant avoids temperature stratification in rooms, but again this doesn't happen in super-insulated homes. In fact, the only way "radiant" heat is actually radiant is if the floor is considerably warmer than your body temperature, which again in a super-insulted home is probably not the case. What is more likely is that heat will be transferred to the air and objects in the room and that the heat source (floor or radiator) will be only somewhat warmer (or only run for a limited amount of time). As a result, I don't even like to call it radiant heat, but rather hydronic or in-floor heat.

The bottom line is that if you want to save energy, super-insulate your house. Once you do, hydronic heat is the best choice, but not for the exaggerated reasons they say. Its because its the most efficient way to move heat around the house.

For a complete discussion on heating systems, click here.

Ventilation
Now that houses are built tight, mechanical and/or passive ventilation is pretty much a requirement (see tight houses for why leaky houses are a bad idea). If your lifestyle is toxic free, you're probably fine using only spot ventilation (on timers), provided you run them every time you generate moisture (cooking, bathing) and for a long enough time, even if your house is quite tight. If this turns out to be not sufficient, then you need whole house ventilation. Often this amounts to a timer that runs a bath fan for a certain amount of time every day, but the problem with this approach is that it gives you the same amount of fresh air every day, no matter the weather or how much your home. This results in the fan running more than necessary and throwing out warm air needlessly. Keep in mind that in the winter, especially on cold, windy days, your house will leak much more air than it does during milder weather, when it may leak very little. Ideally a ventilation controller would give you fresh air only when you need it, but to date (2007) there is no controller that does that--probably partially due to the open question as to exactly what conditions it would measure to determine when to run.

The amount of air a tight house leaks can be modified simply by opening and closing windows from day to day throughout the periods of milder weather. This is a low tech solution that is both highly effective and quite easy to do.

Air filtration will remove much dust and potentially much more, but beyond the basic dust filter, removing more will result in an energy penalty. To make the air significantly cleaner, the fan needs to run for much or all of the day, incurring a large energy cost. The fundamental problem is that the particles that are the biggest health problem are small and so require a very fine filter to remove them--which also makes the fan work harder.

Read more about materials here.

Siding
There is really no environmentally preferred siding product at the moment. Fiber-cement is durable and does not need to be painted as often as wood, but uses a lot of energy to manufacture. Wood, when obtained locally from a sustainably harvested source is much more preferable, but not nearly as durable and needs to be painted often. Vinyl, although durable, is toxic to manufacture. Stucco suffers the same energy problem as fiber-cement, and is probably equally durable.

Read more about materials here.

Construction Lumber
Ideally you'd like to use all FSC certified sustainably harvested wood, salvaged wood or finger joined wood, but in reality its not likely you will find all these materials (2007), although FSC wood is getting much more common. It is especially important to avoid large timbers (say bigger than 6x6) of non FSC origin, since they mostly come from old growth clear-cuts.

SSFI lumber is an industry standard that is weaker than FSC, but still better than standard industry practice. Depending on how you look at it, buying SFI lumber is either encouraging the industry to move toward sustainability, or helping them wipe out FSC as a standard. If your personality allows for it, the best option is to keep asking for FSC as loudly and often as you can, and only buy SFI after you've finished complaining about the lack of FSC.

Read more about materials here.

Finish Lumber
Ideally you'd like to use all locally sources FSC certified sustainably harvested wood, re-milled salvage or paint grade finger jointed wood, but it will take vigilance to source all your material that way (2007). MDF with exterior glue is also acceptable, but interior glue MDF (urea formaldehyde) isn't because it off-gasses for 20 years.

Read more about materials here.

Flooring
The best choices are local hardwood (finished with a low VOC finish), tile and linoleum, since they are low toxic, easy to clean and long lasting. Bamboo and cork are renewable resources, but currently are imported from far away. Soft vinyl flooring is toxic to manufacture, contains toxic phthalates and doesn't last very long. Hard vinyl tile (VCT) is very durable and doesn't contain phthalates would be a choice of last resort, only when other options won't work. Laminate flooring (eg, Pergo) may off-gas, depending on what glue is used and what material the surface is made of and is not recyclable nor biodegradable, so isn't a preferred choice.

Note that linoleum, although a natural product, does off-gas, and occasionally people are sensitive to it.

Carpet is generally considered to be a health hazard as well as a poor environmental choice. The carpet industry has worked hard at instituting recycling programs aimed at reducing how much carpet ends up in the landfill, and also at reducing the level of off-gassing from new carpet.

Read more about materials here.

Countertops
There are a limited number of truly eco-friendly countertop choices, but new ones are coming out often so it is likely that not every product is covered here.

Paperstone and Richlite and are two similar products that are actively courting the "green" market. Richlite is made from sustainably harvested paper and standard phenolic resin, while Paperstone offers a product with 100 post consumer paper and water based non-petroleum based resin. Both are very durable and come in a range of solid colors.

Granite counter tops are very durable, but are mined by removing large chunks of some mountain (mostly not in the US). Quartz composite (Caesarstone, Cambria, Silestone) look much like granite, but are made out of 94% quartz particle (the hardest component of granite) and 6% resin. They are very durable, but their manufactures are not attempting any sustainability claims. Corian (Avonite etc) are very durable, but use a much larger amount of resin than the quartz composites.

Concrete countertops are also durable, but require a large amount of energy to produce. In addition, because concrete is porous, most of them are sealed with expoy. Vetrazzo is a terrazzo like product using recycled glass (reducing the concrete content), but unless you live near Berkley, CA, it might not make sense to ship one.

Tile (including granite tile) is a lower cost alternative which is also very durable, but tends to have mildew problems in the grout around the sink.

Wood (e.g. butcher block) can be a sustainable and fairly durable choice, but needs to be refinished regularly.

Plastic laminate (Formica etc) is often the lowest cost choice, and although they aren't very durable. On the other hand, there isn't that much to throw away when they're worn out. A similar alternative is to use linoleum, which is not petroleum based, but is also not very durable. In both cases, durability is relative: if you're careful, both can last 20 years.

Read more about materials here.

Cabinets
Most cabinets are made with particle board boxes, which typically use urea-formaldehyde resin--which off-gases formaldehyde for around 20 years, and so aren't very good choices. The one exception to this is for Ikea's cabinet line, which use some modified U-F resin that meets strict European off-gassing standards. Look for strawboard or solid wood boxes, preferably FSC certified. Likewise look for the wood content to be FSC certified as well.

AA low-cost option is to use open shelves instead of cabinets.

Read more about materials here.

Salvage Materials/Antiques
The use of salvage materials is limited mostly only by your creativity, and to some degree your determination, since using them is often labor intensive. The labor pays off in having items that are unique pieces of art, giving your home character that can't be obtained any other way.

Plumbing
A simple way to save energy is to reduce the amount of hot water left in the pipe after you turn the faucet off (which also saves water thrown down the drain waiting for hot). The best way is to locate all your plumbing fixtures close to the hot water heater, but when that isn't possible, using a "home run" plumbing system is second best (and obviously doing both will save even more). In a home run system, each fixture gets its own (skinny) pipe all the way back to very close to the hot water (typically a foot or two). In a standard system, there is a fat pipe typically runs quite far, resulting in there being much more water sitting between the heater and the faucet. Home run systems all use PEX (plastic), but not all PEX systems are home run. PEX is not without health concerns, but then neither is copper, and which is the healthier choice is very controversial.

Low flow faucets and shower heads (2.5GPM or less) should be the default choice. There are now ultra low flow (1.5GPM) shower head as well. A good compromise option is a shower faucet that has a volume control on it (as well as temperature), allowing you to run at lower volume much of the time and only turning it up when you want a quick rinse.

Low water use toilets (1.6GPM) are now being replaced by ultra low flow (1.3GPM) and dual flush models. The best choice is always one that only requires one flush to clear the bowl--consult www.savingwater.org to find the best performing models.

Rainwater
If you have access to municipal water, and its not terribly expensive (most of them aren't), a rainwater system won't make much economic sense. They can still make environmental sense in climates with seasonal rainfall (most of the west), since they act as additional storage capacity, saving the impact of building additional storage capacity. The simplest uses of rainwater are for non-potable use-landscaping, toilets and maybe laundry.

The key to a successful rainwater system is keeping crud out of the tank...which means keeping it out of your gutters or filtering it out before the water gets in the tank. Unless the water is kept very clean, you will most likely want an additional filter before using it for toilets, and certainly for laundry.

Tanks are typically plastic (polyethylene), metal or concrete, with typically cost ranging from fifty cents a gallon to a dollar a gallon, plus installation cost. Underground tanks tend to be more expensive than above ground storage. The necessary size depends on how long the dry season is and how much you need per day: in most cases this will be thousands of gallons.

Unless you can collect the water at least 50' higher than you use it (providing about 20psi), you will need a pump to supply adequate pressure, which means that when the pump dies (which they all inevitably do) or the power goes out, you'll be without water from your tank until the problem is resolved.

On the plus side, you can water your yard guilt free, even when there is a drought!

Landscaping
Turf grass is easily adaptable to industrial maintenance, but is otherwise an environmental disaster: the fertilizers and herbicides applied to lawns pollute groundwater and stream, and the power mowers spew large amount of air pollution, as well as consuming petroleum. In addition, turf grass requires large amounts of water to keep green. If you really want turf grass, use organic fertilizers and consider allowing other plants, like clover and yarrow into the mix, keeping in mind that nature never produces mono-cultures. A push mower or electric mower will reduce pollution emissions significantly.

Perennials and shrubs make much more interesting landscapes (although admittedly you can't play on them), and when properly selected, will generally use less water and fertilizer than turf grass.

No matter which type of landscaping you use, starting with good soil will make you plants happier and reduce your fertilizer needs.